Abstract
The mass domain where massive extrasolar planets and brown dwarfs overlap is still poorly understood due to the paucity of brown dwarfs orbiting close to solar-type stars, the so-called brown dwarf desert. In this paper, we collect all available data about close brown dwarfs around solar-type stars and their host stars from literature and study the demographics of the brown dwarf desert. The data clearly show a short period and a medium mass gap in the brown dwarf period–mass distribution diagram (35 < m sin i < 55MJup and P < 100 d), representing the ‘driest land’ in the brown dwarf desert. Observation biases are highly unlikely to cause this gap due to its short period and medium mass, of which brown dwarfs can be easily detected by previous radial velocity surveys. Brown dwarfs above and below this gap have significantly different eccentricity distribution, which not only confirms that this gap is real, but also implies that they may have different origins. Our further statistical study indicates that brown dwarfs below this gap may primarily form in the protoplanetary disc through disc gravitational instability, while brown dwarfs above this gap may dominantly form like a stellar binary through molecular cloud fragmentation. Our discoveries have offered important insights about brown dwarf formation mechanisms and their possible relationships with planet and star formation.
1 INTRODUCTION
Brown dwarfs (BD) are in the mass range approximately 13–80 Jupiter masses, having sufficient masses to burn deuterium but not enough to burn hydrogen in their inner cores (Burrows et al. 1997, 2001; Chabrier & Baraffe 2000; Spiegel, Burrows & Milsom 2011). The first discovery of a bona-fide BD (Nakajima et al. 1995; Oppenheimer et al. 1995; Rebolo, Zapatero Osorio & Martín 1995; Basri, Marcy & Graham 1996; Rebolo et al. 1996) came in the same year as the discovery of the first extrasolar planet around a solar-type star, 51 Peg b (Mayor & Queloz 1995). One of the major achievements of high-precision radial velocity (RV) surveys over the past two decades is the identification of a BD desert, a paucity of BD companions relative to planets within 3 au around main-sequence FGKM stars (Campbell, Walker & Yang 1988; Murdoch, Hearnshaw & Clark 1993; Marcy & Butler 2000; Grether & Lineweaver 2006). Although the induced reflex RV signal by a close BD companion on a solar-type star is well within the detection sensitivities of the high-precision RV surveys (∼3–10 m s−1), only a few dozen are known (Reid & Metchev 2008; Sahlmann et al. 2011a, and references therein) compared to over 500 giant planets detected so far by the RV technique. The California & Carnegie Planet Search measured an occurrence rate of 0.7 ± 0.2 per cent from their sample of ∼1000 target stars (Vogt et al. 2002; Patel et al. 2007), and the McDonald Observatory Planet Search shows a similar rate of 0.8 ± 0.6 per cent from a search sample of 250 stars (Wittenmyer et al. 2009). Sahlmann et al. (2011a) obtained an upper limit of 0.6 per cent for the frequency of close BD companions based on the uniform stellar sample of the CORALIE planet search, which contains 1600 solar-type stars within 50 pc.
To assess the reality of the BD desert, Grether & Lineweaver (2006) performed a detailed investigation of the companions around nearby Sun-like stars. They found that approximately 16 per cent of nearby Sun-like stars have close (P < 5 yr) companions more massive than Jupiter: 11 ± 3 per cent are stellar companions, <1 per cent are BDs and 5 ± 2 per cent are giant planets. Although the close BDs are rare around solar-type stars, Gizis et al. (2001) suggest that BDs might not be as rare at wide separations (see also Metchev & Hillenbrand 2004) as at close separations. Lafrenière et al. (2007) obtained a 95 per cent confidence interval of |$1.9^{+8.3}_{-1.5}$| per cent for the frequency of 13|$\text{--}$|75MJup companions between 25 and 250 au in the Gemini Deep Planet Survey around 85 nearby young stars. Metchev & Hillenbrand (2009) inferred that the frequency of BDs in 28–1590 au orbits around young solar analogues is |$3.2^{+3.1}_{-2.7}$| per cent from an adaptive optics survey for substellar companions around 266 Sun-like stars.
BDs are traditionally believed to form like stars, through gravitational collapse and/or fragmentation of molecular clouds (Padoan & Nordlund 2004; Hennebelle & Chabrier 2008). A recently found self-gravitating clump of gas and dust has a mass (0.015–0.03 M⊙) in the BD regime (André, Ward-Thompson & Greaves 2012), which supports the idea that BDs could form like a star. On the other hand, companions with masses up to 10MJup (Alibert et al. 2005) or even 38MJup (Mordasini, Alibert & Benz 2009) may form in protoplanetary discs according to the standard core-accretion planet formation theory. Because of this, the BD desert is commonly interpreted as the gap between the largest mass objects that can be formed in protoplanetary discs and the smallest mass clumps that can collapse and/or fragment in the vicinity of a protostar. The mass function of close stellar companions shows a linear decrease in log(M) towards the BD mass range from both stellar mass and planetary mass directions (Grether & Lineweaver 2006). In comparison, the mass function of isolated substellar objects seems to be roughly flat in log(M) down to masses ∼20MJup, both in the field and in clusters (Luhman et al. 2000; Chabrier 2002). This indicates that close BD companions may form in a different way from those formed in the field and clusters.
As such, statistical properties of close BD companions as well as how these properties are related to their host stars contain a lot of information about the poorly understood BD formation mechanisms and their relationships with star and planet formations in close orbital environments. These statistics may also be important to investigating how additional important processes such as tidal evolution and disc–planet interaction affect close BD properties (e.g. Armitage & Bonnell 2002; Matzner & Levin 2005). Given that the close BD occurrence rate is <1 per cent, currently there has yet been a single large, relatively uniform RV survey capable of producing a large homogeneous sample of BD companions for a meaningful statistical study. However, all of the previous major RV planet surveys have sufficient RV sensitivity and time baseline (Marcy, Cochran & Mayor 2000; Udry et al. 2000; Jones et al. 2002; Ge et al. 2008; Wittenmyer et al. 2009; Lo Curto et al. 2010; Eisenstein et al. 2011) to detect a majority of close BDs around solar-type stars due to the large RV amplitude (of the order of ∼1000 m s−1). It is, therefore, possible to combine close BD companion samples together for a statistical study without major biases.
In this paper, we assembled a catalogue of all the BD companions discovered around solar-type star from literature and used it to conduct a statistical study. We have found tentative evidence for the existence of two different populations of BD companions. We present the BD catalogue assembled in this study in Section 2, statistical properties of BD companions in Section 3 and discuss their implication for different BD formation scenarios in Section 4. We summarize our main results in Section 5.
2 CATALOGue DESCRIPTION
We have collected data from literature about the currently known BD (candidates) companions around FGK-type stars. Most of them have known Keplerian orbits, except for HIP 78530 (discovered by direct imaging; Lafrenière et al. 2011) and KOI-554.01 (unpublished yet; Santerne et al. 2012). Properties of the BDs (minimum mass, period and eccentricity) and their host stars (mass, effective temperature, surface gravity and metallicity) are summarized in Table 1. For those which are transiting their parent stars or have astrometry measurements, true masses are also given besides M sin i.
Close BD (candidate) companions to solar-type stars.
| Object | Mc | Mc sin i | Period | Eccentricity | M⋆ | Teff | log (g) | [Fe/H] | References |
|---|---|---|---|---|---|---|---|---|---|
| (MJup) | (MJup) | (d) | (M⊙) | (K) | (cgs) | ||||
| HD 52756 | – | |$59.3^{+ 2.0}_{-1.9}$| | 52.8657 ± 0.0001 | 0.6780 ± 0.0003 | 0.83 ± 0.01 | 5216 ± 65 | 4.47 ± 0.11 | 0.13 ± 0.05 | 1 |
| HD 89707 | – | |$53.6^{+7.8}_{-6.9}$| | 298.5 ± 0.1 | 0.900|$^{+0.039}_{-0.035}$| | 0.96 ± 0.04 | 6047 ± 50 | 4.52 ± 0.10 | −0.33 ± 0.06 | 1 |
| HD 167665 | – | 50.6 ± 1.7 | 4451.8|$^{+27.6}_{-27.3}$| | 0.340 ± 0.005 | 1.14 ± 0.03 | 6224 ± 50 | 4.44 ± 0.10 | −0.05 ± 0.06 | 1 |
| HD 189310 | – | |$25.6^{+0.9}_{-0.8}$| | 14.186 43 ± 0.000 02 | 0.359 ± 0.001 | 0.83 ± 0.02 | 5188 ± 50 | 4.49 ± 0.10 | −0.01 ± 0.06 | 1 |
| HD 4747 | – | 46.1 ± 2.3 | 11 593.2|$^{+1118.6}_{-1117.6}$| | 0.723 ± 0.013 | 0.81 ± 0.02 | 5316 ± 50 | 4.48 ± 0.10 | −0.21 ± 0.05 | 1 |
| HD 211847 | – | 19.2 ± 1.2 | 7929.40|$^{+1999.1}_{-2500.2}$| | |$0.685^{+0.068}_{-0.067}$| | 0.94 ± 0.04 | 5715 ± 50 | 4.49 ± 0.10 | −0.08 ± 0.06 | 1 |
| HD 180314 | – | 22.0 | 396.03 ± 0.62 | 0.257 ± 0.010 | 2.6 ± 0.3 | 4917 ± 100 | 2.98 ± 0.12 | 0.2 ± 0.09 | 3 |
| HD 13189 | – | 20.0 | 471.6 ± 6.0 | 0.27 ± 0.06 | 7 | 5000 ± 100 | 2.0 ± 0.1 | 0.0 ± 0.10 | 4 |
| HD 30339 | – | 77.8 | 15.0778 ± 0.000 | 0.25 | 1.1 | 6074 ± 100 | 4.37 ± 0.10 | 0.21 ± 0.10 | 4 |
| HD 65430 | – | 67.8 | 3138 ± 342 | 0.32 | 0.78 | 5183 ± 100 | 4.55 ± 0.10 | −0.04 ± 0.10 | 4 |
| HD 140913 | – | 43.2 | 147.968 ± 0.000 | 0.54 | 0.98 | 6048 ± 100 | 4.57 ± 0.10 | 0.07 ± 0.10 | 4 |
| HD 38529c | 17.6|$^{+1.5}_{-1.2}$| | 13.99 ± 0.59 | 2136.14 ± 0.29 | 0.362 ± 0.002 | 1.48 ± 0.05 | 5697 | 3.94 ± 0.10 | +0.27 ± 0.05 | 5 |
| HD 91669 | – | 30.6 ± 2.1 | 497.5 ± 0.6 | 0.448 ± 0.002 | |$0.914^{+0.018}_{-0.087}$| | 5185 ± 87 | 4.48 ± 0.20 | +0.31 ± 0.08 | 6 |
| 11Com | – | 19.4 ± 1.5 | 326.03 ± 0.32 | 0.231 ± 0.005 | 2.7 ± 0.3 | 4742 ± 100 | 2.31 ± 0.10 | −0.35 ± 0.09 | 7 |
| HD 119445 | – | 37.6 ± 2.6 | 410.2 ± 0.6 | 0.082 ± 0.007 | 3.9 ± 0.4 | 5083 ± 103 | 2.40 ± 0.17 | 0.04 ± 0.18 | 8 |
| HD 131664 | |$23^{+26.0}_{-5.0}$| | – | 1951 ± 41 | 0.638 ± 0.02 | 1.10 ± 0.03 | 5886 ± 21 | 4.44 ± 0.10 | +0.32 ± 0.02 | 9, 56 |
| GJ 595 | – | 60.0 ± 0.0 | 62.6277 ± 0.0001 | 0.26 ± 0.001 | 0.28 | 3500 ± 100 | 4.83 ± 0.10 | 0.0 ± 0.10 | 4 |
| HD 162020 | – | 14.4 ± 0.04 | 8.428 198 ± 0.000 056 | 0.277 ± 0.002 | 0.75 | 4830 ± 80 | 4.76 ± 0.25 | +0.01 ± 0.11 | 12 |
| HD 168443 | 34.3 ± 9.0 | – | 1748.2 ± 1.0 | 0.2122 ± 0.0020 | 1.01 ± 0.05 | 5555 ± 40 | 4.10 ± 0.12 | +0.10 ± 0.03 | 1, 12, 22 |
| HD 180777 | – | 25.0 ± 0.0 | 28.44 ± 0.01 | 0.20 | 1.7 ± 0.1 | 7250 | 4.34 | −0.16 | 1, 24, 25 |
| HD 190228 | 49.4 ± 14.8 | – | 1146 ± 16 | 0.50 ± 0.04 | 0.83 | 5360 ± 40 | 4.02 ± 0.10 | −0.24 ± 0.06 | 1, 26 |
| HD 191760 | – | 38.17 ± 1.02 | 505.65 ± 0.42 | 0.63 ± 0.01 | 1.28|$^{+0.02}_{-0.10}$| | 5821 ± 82 | 4.13|$^{+0.05}_{-0.04}$| | 0.29 ± 0.07 | 1, 27 |
| HD 202206 | – | 17.5 | 256.20 ± 0.03 | 0.433 ± 0.001 | 1.15 | 5765 ± 40 | 4.75 ± 0.20 | 0.37 ± 0.07 | 1, 12, 28 |
| HIP 21832 | 40.9 ± 26.2 | – | 1474.9 ± 10.2 | 0.356 ± 0.095 | 1.0 ± 0.0 | 5554 ± 70 | 4.32 ± 0.10 | −0.63 ± 0.10 | 17 |
| HD 14651 | – | 47.0 ± 3.4 | 79.4179 ± 0.0021 | 0.4751 ± 0.0010 | 0.96 ± 0.03 | 5491 ± 26 | 4.45 ± 0.03 | −0.04 ± 0.06 | 18 |
| HD 30246 | – | 55.1|$^{+20.3}_{-8.2}$| | 990.7 ± 5.6 | 0.838 ± 0.081 | 1.05 ± 0.04 | 5833 ± 44 | 4.39 ± 0.04 | +0.17 ± 0.10 | 18 |
| HD 92320 | – | 59.4 ± 4.1 | 145.4 ± 0.01 | 0.323 | 0.92 ± 0.04 | 5664 ± 24 | 4.48 ± 0.03 | −0.10 ± 0.06 | 18 |
| HD 22781 | – | 13.65 ± 0.97 | 528.07 ± 0.14 | 0.8191 ± 0.0023 | 0.75 ± 0.03 | 5027 ± 50 | 4.60 ± 0.02 | −0.37 ± 0.12 | 18 |
| HD 137510 | 20.0–60.0 | 27.3 ± 1.9 | 801.30 ± 0.45 | 0.3985 ± 0.0073 | 1.36 ± 0.04 | 6131 ± 50 | 4.02 ± 0.04 | 0.38 ± 0.13 | 10, 11, 18, |
| HIP 5158 | – | 15.04 ± 10.55 | 9017.76 ± 3180.74 | 0.14 ± 0.10 | 0.780 ± 0.021 | 4962 ± 89 | 4.37 ± 0.20 | 0.10 ± 0.07 | 29, 52 |
| HD 41004B | – | 18.37 ± 0.22 | 1.328 300 ± 0.000 012 | 0.081 ± 0.012 | 0.40 ± 0.04 | – | – | – | 30 |
| HAT-P-13c | – | 14.28 ± 0.28 | 446.27 ± 0.22 | 0.6616 ± 0.0054 | 1.22|$^{+0.05}_{-0.10}$| | 5640 ± 90 | 4.13 ± 0.04 | 0.430 ± 0.08 | 31 |
| BD+202457b | – | 22.7 ± 8.1 | 379.63 ± 2.01 | 0.15 ± 0.03 | 2.8 ± 1.5 | 4137 ± 10 | 1.51 ± 0.05 | −1.00 ± 0.07 | 32 |
| BD+202457c | – | 13.2 ± 4.7 | 621.99 ± 10.20 | 0.18 ± 0.06 | 2.8 ± 1.5 | 4137 ± 10 | 1.51 ± 0.05 | −1.00 ± 0.07 | 32 |
| HD 137759 | – | 12.7 ± 1.08 | 511.098 ± 0.089 | 0.7124 ± 0.0039 | 1.80 ± 0.23 | 4500 ± 110 | 2.74 ± 0.10 | 0.03 ± 0.10 | 11, 33, 35 |
| NGC 2423−3b | – | 10.64 ± 0.93 | 714.3 ± 5.3 | 0.21 ± 0.07 | 2.4 ± 0.2 | – | – | – | 36, 37 |
| NGC 4349−127b | – | 20.0 ± 1.73 | 678.0 ± 6.2 | 0.19 | 3.9 ± 0.3 | 4569 ± 69 | 2.08 ± 0.35 | −0.13 ± 0.18 | 36, 37 |
| HD 16760b | – | 13.13 ± 0.56 | 466.47 ± 0.35 | 0.084 ± 0.003 | 0.78 ± 0.05 | 5629 ± 44 | 4.47 ± 0.06 | +0.067 ± 0.05 | 38 |
| HD 10697 | 38 ± 13 | – | 1075.0 ± 1.5 | 0.099 ± 0.007 | 1.112|$^{+0.026}_{-0.02}$| | 5680 ± 44 | 4.12 ± 0.06 | 0.19 ± 0.03 | 40, 41, 42 |
| HD 114762 | – | 10.99 ± 0.09 | 83.9152 ± 0.0028 | 0.3325 | 0.89 ± 0.09 | 5950 ± 44 | 4.54 ± 0.06 | −0.65 ± 0.03 | 11, 34, 43 |
| TYC 2534-698-1 | – | 39.1 ± 11.5 | 103.698 ± 0.111 000 | 0.385 | 0.998 ± 0.040 | 5700 ± 80 | 4.50 ± 0.10 | −0.25 ± 0.06 | 44 |
| TYC 2949-557-1 | – | 64.3 ± 3.0 | 5.694 49 ± 0.000 29 | 0.0017|$^{+0.0019}_{-0.0017}$| | 1.25 ± 0.09 | 6135 ± 40 | 4.4 ± 0.1 | 0.32 ± 0.01 | 45 |
| TYC 1240-945-1 | – | 28.0 ± 1.5 | 5.8953 ± 0.0004 | 0.015 ± 0.011 | 1.37 ± 0.11 | 6186 ± 92 | 3.89 ± 0.07 | −0.15 ± 0.04 | 16 |
| HIP 67526 | – | 62.6 ± 0.6 | 90.2695 ± 0.0188 | 0.4375 ± 0.0040 | 1.11 ± 0.08 | 6004 ± 29 | 4.55 ± 0.15 | 0.04 ± 0.05 | 63 |
| TYC 2930-872-1 | – | 68.1 ± 3.0 | 2.430 420 ± 0.000 006 | 0.0066 ± 0.0010 | 1.21 ± 0.08 | 6427 ± 33 | 4.52 ± 0.14 | −0.04 ± 0.05 | 58 |
| TYC 2087-255-1 | – | 40.0 ± 1.8 | 9.0090 ± 0.0004 | 0.226 ± 0.011 | 1.16 ± 0.08 | 5903 ± 42 | 4.07 ± 0.16 | −0.23 ± 0.07 | 21 |
| TYC 3130-160 | – | 57.4 ± 3.0 | 31.66 ± 0.023 | 0.688 | 1.0 ± 0.1 | 5104 ± 50 | 4.43 ± 0.10 | 0.01 ± 0.05 | 62 |
| HIP 78530 | – | 23 ± 3 | ∼4.38 × 106 | 0 (fixed) | 2.5 ± 0.2 | 10500 ± 500 | – | – | 46 |
| HD 5388b | 69.2 ± 19.9 | – | 777.0 ± 4.0 | 0.40 ± 0.02 | 1.21 ± 0.10 | 6297 ± 32 | 4.28 ± 0.06 | −0.27 ± 0.02 | 48, 53 |
| HR 7672b | 68.7 ± 3.0 | – | 26 772|$^{+803.5}_{-1059.2}$| | 0.5 | 1.08 ± 0.04 | 5883 ± 59 | 4.42 ± 0.06 | 0.05 ± 0.07 | 49 |
| HD 175679 | – | 37.3 ± 2.8 | 1366.8 ± 5.7 | 0.378 ± 0.008 | 2.7 ± 0.3 | 4844 ± 100 | 2.59 ± 0.10 | −0.14 ± 0.10 | 50 |
| HD 136118 | |$42^{+11}_{-18}$| | 12.0 ± 0.47 | 1188.0 ± 2.0 | 0.34 ± 0.01 | 1.24 ± 0.07 | 6097 ± 44 | 4.16 ± 0.09 | −0.01 ± 0.05 | 59, 60 |
| HD 217786 | – | 13.0 ± 0.8 | 1319 ± 4 | 0.40 ± 0.05 | 1.02 ± 0.03 | 5966 ± 65 | 4.35 ± 0.11 | −0.135 ± 0.043 | 61 |
| WASP-30 | 60.96 ± 0.89 | – | 4.156 736 ± 0.000 013 | 0 (adopted) | 1.17 ± 0.03 | 6201 ± 97 | 4.28 ± 0.01 | −0.03 ± 0.10 | 13 |
| COROT-15 | 63.3 ± 4.1 | – | 3.060 36 ± 0.000 03 | 0 (adopted) | 1.32 ± 0.12 | 6350 ± 200 | 4.3 ± 0.2 | 0.10 ± 0.20 | 14 |
| LHS 6343 | 62.9 ± 2.3 | – | 12.713 82 ± 0.000 04 | 0.056 ± 0.032 | 0.370 ± 0.009 | – | 4.851 ± 0.008 | 0.04 ± 0.08 | 15 |
| Corot-3b | 21.66 ± 1.00 | – | 4.256 80 ± 0.000 005 | 0 (adopted) | 1.37 ± 0.09 | 6740 ± 140 | 4.22 ± 0.07 | −0.02 ± 0.06 | 19 |
| XO-3b | 11.8 ± 0.59 | – | 3.191 5239 ± 0.000 0068 | 0.26 ± 0.017 | 1.213 ± 0.066 | 6429 ± 100 | 4.244 ± 0.041 | −0.177 ± 0.080 | 20 |
| KOI-423b | 18.0|$^{+0.93}_{-0.91}$| | – | 21.0874 ± 0.0002 | 0.121|$^{+0.022}_{-0.023}$| | 1.1|$^{+0.07}_{-0.06}$| | 6260 ± 140 | 4.1 ± 0.2 | −0.29 ± 0.10 | 23 |
| KELT-1b | 27.23|$^{+0.5}_{-0.48}$| | – | 1.217 514 ± 0.000 015 | 0.0099|$^{+0.01}_{-0.0069}$| | 1.324 ± 0.026 | 6518 ± 50 | 4.229|$^{+0.012}_{-0.019}$| | 0.008 ± 0.073 | 56 |
| KOI-554.01 | 80 | – | 3.66 | – | – | 5835 | 4.64 | −0.08 | 57 |
| KOI-205.01 | 39.9 ± 1.0 | – | 11.720 125 ± 0.000 002 | <0.031 | 0.925 ± 0.033 | 5237 ± 60 | 4.57 | 0.14 ± 0.12 | 64 |
| Object | Mc | Mc sin i | Period | Eccentricity | M⋆ | Teff | log (g) | [Fe/H] | References |
|---|---|---|---|---|---|---|---|---|---|
| (MJup) | (MJup) | (d) | (M⊙) | (K) | (cgs) | ||||
| HD 52756 | – | |$59.3^{+ 2.0}_{-1.9}$| | 52.8657 ± 0.0001 | 0.6780 ± 0.0003 | 0.83 ± 0.01 | 5216 ± 65 | 4.47 ± 0.11 | 0.13 ± 0.05 | 1 |
| HD 89707 | – | |$53.6^{+7.8}_{-6.9}$| | 298.5 ± 0.1 | 0.900|$^{+0.039}_{-0.035}$| | 0.96 ± 0.04 | 6047 ± 50 | 4.52 ± 0.10 | −0.33 ± 0.06 | 1 |
| HD 167665 | – | 50.6 ± 1.7 | 4451.8|$^{+27.6}_{-27.3}$| | 0.340 ± 0.005 | 1.14 ± 0.03 | 6224 ± 50 | 4.44 ± 0.10 | −0.05 ± 0.06 | 1 |
| HD 189310 | – | |$25.6^{+0.9}_{-0.8}$| | 14.186 43 ± 0.000 02 | 0.359 ± 0.001 | 0.83 ± 0.02 | 5188 ± 50 | 4.49 ± 0.10 | −0.01 ± 0.06 | 1 |
| HD 4747 | – | 46.1 ± 2.3 | 11 593.2|$^{+1118.6}_{-1117.6}$| | 0.723 ± 0.013 | 0.81 ± 0.02 | 5316 ± 50 | 4.48 ± 0.10 | −0.21 ± 0.05 | 1 |
| HD 211847 | – | 19.2 ± 1.2 | 7929.40|$^{+1999.1}_{-2500.2}$| | |$0.685^{+0.068}_{-0.067}$| | 0.94 ± 0.04 | 5715 ± 50 | 4.49 ± 0.10 | −0.08 ± 0.06 | 1 |
| HD 180314 | – | 22.0 | 396.03 ± 0.62 | 0.257 ± 0.010 | 2.6 ± 0.3 | 4917 ± 100 | 2.98 ± 0.12 | 0.2 ± 0.09 | 3 |
| HD 13189 | – | 20.0 | 471.6 ± 6.0 | 0.27 ± 0.06 | 7 | 5000 ± 100 | 2.0 ± 0.1 | 0.0 ± 0.10 | 4 |
| HD 30339 | – | 77.8 | 15.0778 ± 0.000 | 0.25 | 1.1 | 6074 ± 100 | 4.37 ± 0.10 | 0.21 ± 0.10 | 4 |
| HD 65430 | – | 67.8 | 3138 ± 342 | 0.32 | 0.78 | 5183 ± 100 | 4.55 ± 0.10 | −0.04 ± 0.10 | 4 |
| HD 140913 | – | 43.2 | 147.968 ± 0.000 | 0.54 | 0.98 | 6048 ± 100 | 4.57 ± 0.10 | 0.07 ± 0.10 | 4 |
| HD 38529c | 17.6|$^{+1.5}_{-1.2}$| | 13.99 ± 0.59 | 2136.14 ± 0.29 | 0.362 ± 0.002 | 1.48 ± 0.05 | 5697 | 3.94 ± 0.10 | +0.27 ± 0.05 | 5 |
| HD 91669 | – | 30.6 ± 2.1 | 497.5 ± 0.6 | 0.448 ± 0.002 | |$0.914^{+0.018}_{-0.087}$| | 5185 ± 87 | 4.48 ± 0.20 | +0.31 ± 0.08 | 6 |
| 11Com | – | 19.4 ± 1.5 | 326.03 ± 0.32 | 0.231 ± 0.005 | 2.7 ± 0.3 | 4742 ± 100 | 2.31 ± 0.10 | −0.35 ± 0.09 | 7 |
| HD 119445 | – | 37.6 ± 2.6 | 410.2 ± 0.6 | 0.082 ± 0.007 | 3.9 ± 0.4 | 5083 ± 103 | 2.40 ± 0.17 | 0.04 ± 0.18 | 8 |
| HD 131664 | |$23^{+26.0}_{-5.0}$| | – | 1951 ± 41 | 0.638 ± 0.02 | 1.10 ± 0.03 | 5886 ± 21 | 4.44 ± 0.10 | +0.32 ± 0.02 | 9, 56 |
| GJ 595 | – | 60.0 ± 0.0 | 62.6277 ± 0.0001 | 0.26 ± 0.001 | 0.28 | 3500 ± 100 | 4.83 ± 0.10 | 0.0 ± 0.10 | 4 |
| HD 162020 | – | 14.4 ± 0.04 | 8.428 198 ± 0.000 056 | 0.277 ± 0.002 | 0.75 | 4830 ± 80 | 4.76 ± 0.25 | +0.01 ± 0.11 | 12 |
| HD 168443 | 34.3 ± 9.0 | – | 1748.2 ± 1.0 | 0.2122 ± 0.0020 | 1.01 ± 0.05 | 5555 ± 40 | 4.10 ± 0.12 | +0.10 ± 0.03 | 1, 12, 22 |
| HD 180777 | – | 25.0 ± 0.0 | 28.44 ± 0.01 | 0.20 | 1.7 ± 0.1 | 7250 | 4.34 | −0.16 | 1, 24, 25 |
| HD 190228 | 49.4 ± 14.8 | – | 1146 ± 16 | 0.50 ± 0.04 | 0.83 | 5360 ± 40 | 4.02 ± 0.10 | −0.24 ± 0.06 | 1, 26 |
| HD 191760 | – | 38.17 ± 1.02 | 505.65 ± 0.42 | 0.63 ± 0.01 | 1.28|$^{+0.02}_{-0.10}$| | 5821 ± 82 | 4.13|$^{+0.05}_{-0.04}$| | 0.29 ± 0.07 | 1, 27 |
| HD 202206 | – | 17.5 | 256.20 ± 0.03 | 0.433 ± 0.001 | 1.15 | 5765 ± 40 | 4.75 ± 0.20 | 0.37 ± 0.07 | 1, 12, 28 |
| HIP 21832 | 40.9 ± 26.2 | – | 1474.9 ± 10.2 | 0.356 ± 0.095 | 1.0 ± 0.0 | 5554 ± 70 | 4.32 ± 0.10 | −0.63 ± 0.10 | 17 |
| HD 14651 | – | 47.0 ± 3.4 | 79.4179 ± 0.0021 | 0.4751 ± 0.0010 | 0.96 ± 0.03 | 5491 ± 26 | 4.45 ± 0.03 | −0.04 ± 0.06 | 18 |
| HD 30246 | – | 55.1|$^{+20.3}_{-8.2}$| | 990.7 ± 5.6 | 0.838 ± 0.081 | 1.05 ± 0.04 | 5833 ± 44 | 4.39 ± 0.04 | +0.17 ± 0.10 | 18 |
| HD 92320 | – | 59.4 ± 4.1 | 145.4 ± 0.01 | 0.323 | 0.92 ± 0.04 | 5664 ± 24 | 4.48 ± 0.03 | −0.10 ± 0.06 | 18 |
| HD 22781 | – | 13.65 ± 0.97 | 528.07 ± 0.14 | 0.8191 ± 0.0023 | 0.75 ± 0.03 | 5027 ± 50 | 4.60 ± 0.02 | −0.37 ± 0.12 | 18 |
| HD 137510 | 20.0–60.0 | 27.3 ± 1.9 | 801.30 ± 0.45 | 0.3985 ± 0.0073 | 1.36 ± 0.04 | 6131 ± 50 | 4.02 ± 0.04 | 0.38 ± 0.13 | 10, 11, 18, |
| HIP 5158 | – | 15.04 ± 10.55 | 9017.76 ± 3180.74 | 0.14 ± 0.10 | 0.780 ± 0.021 | 4962 ± 89 | 4.37 ± 0.20 | 0.10 ± 0.07 | 29, 52 |
| HD 41004B | – | 18.37 ± 0.22 | 1.328 300 ± 0.000 012 | 0.081 ± 0.012 | 0.40 ± 0.04 | – | – | – | 30 |
| HAT-P-13c | – | 14.28 ± 0.28 | 446.27 ± 0.22 | 0.6616 ± 0.0054 | 1.22|$^{+0.05}_{-0.10}$| | 5640 ± 90 | 4.13 ± 0.04 | 0.430 ± 0.08 | 31 |
| BD+202457b | – | 22.7 ± 8.1 | 379.63 ± 2.01 | 0.15 ± 0.03 | 2.8 ± 1.5 | 4137 ± 10 | 1.51 ± 0.05 | −1.00 ± 0.07 | 32 |
| BD+202457c | – | 13.2 ± 4.7 | 621.99 ± 10.20 | 0.18 ± 0.06 | 2.8 ± 1.5 | 4137 ± 10 | 1.51 ± 0.05 | −1.00 ± 0.07 | 32 |
| HD 137759 | – | 12.7 ± 1.08 | 511.098 ± 0.089 | 0.7124 ± 0.0039 | 1.80 ± 0.23 | 4500 ± 110 | 2.74 ± 0.10 | 0.03 ± 0.10 | 11, 33, 35 |
| NGC 2423−3b | – | 10.64 ± 0.93 | 714.3 ± 5.3 | 0.21 ± 0.07 | 2.4 ± 0.2 | – | – | – | 36, 37 |
| NGC 4349−127b | – | 20.0 ± 1.73 | 678.0 ± 6.2 | 0.19 | 3.9 ± 0.3 | 4569 ± 69 | 2.08 ± 0.35 | −0.13 ± 0.18 | 36, 37 |
| HD 16760b | – | 13.13 ± 0.56 | 466.47 ± 0.35 | 0.084 ± 0.003 | 0.78 ± 0.05 | 5629 ± 44 | 4.47 ± 0.06 | +0.067 ± 0.05 | 38 |
| HD 10697 | 38 ± 13 | – | 1075.0 ± 1.5 | 0.099 ± 0.007 | 1.112|$^{+0.026}_{-0.02}$| | 5680 ± 44 | 4.12 ± 0.06 | 0.19 ± 0.03 | 40, 41, 42 |
| HD 114762 | – | 10.99 ± 0.09 | 83.9152 ± 0.0028 | 0.3325 | 0.89 ± 0.09 | 5950 ± 44 | 4.54 ± 0.06 | −0.65 ± 0.03 | 11, 34, 43 |
| TYC 2534-698-1 | – | 39.1 ± 11.5 | 103.698 ± 0.111 000 | 0.385 | 0.998 ± 0.040 | 5700 ± 80 | 4.50 ± 0.10 | −0.25 ± 0.06 | 44 |
| TYC 2949-557-1 | – | 64.3 ± 3.0 | 5.694 49 ± 0.000 29 | 0.0017|$^{+0.0019}_{-0.0017}$| | 1.25 ± 0.09 | 6135 ± 40 | 4.4 ± 0.1 | 0.32 ± 0.01 | 45 |
| TYC 1240-945-1 | – | 28.0 ± 1.5 | 5.8953 ± 0.0004 | 0.015 ± 0.011 | 1.37 ± 0.11 | 6186 ± 92 | 3.89 ± 0.07 | −0.15 ± 0.04 | 16 |
| HIP 67526 | – | 62.6 ± 0.6 | 90.2695 ± 0.0188 | 0.4375 ± 0.0040 | 1.11 ± 0.08 | 6004 ± 29 | 4.55 ± 0.15 | 0.04 ± 0.05 | 63 |
| TYC 2930-872-1 | – | 68.1 ± 3.0 | 2.430 420 ± 0.000 006 | 0.0066 ± 0.0010 | 1.21 ± 0.08 | 6427 ± 33 | 4.52 ± 0.14 | −0.04 ± 0.05 | 58 |
| TYC 2087-255-1 | – | 40.0 ± 1.8 | 9.0090 ± 0.0004 | 0.226 ± 0.011 | 1.16 ± 0.08 | 5903 ± 42 | 4.07 ± 0.16 | −0.23 ± 0.07 | 21 |
| TYC 3130-160 | – | 57.4 ± 3.0 | 31.66 ± 0.023 | 0.688 | 1.0 ± 0.1 | 5104 ± 50 | 4.43 ± 0.10 | 0.01 ± 0.05 | 62 |
| HIP 78530 | – | 23 ± 3 | ∼4.38 × 106 | 0 (fixed) | 2.5 ± 0.2 | 10500 ± 500 | – | – | 46 |
| HD 5388b | 69.2 ± 19.9 | – | 777.0 ± 4.0 | 0.40 ± 0.02 | 1.21 ± 0.10 | 6297 ± 32 | 4.28 ± 0.06 | −0.27 ± 0.02 | 48, 53 |
| HR 7672b | 68.7 ± 3.0 | – | 26 772|$^{+803.5}_{-1059.2}$| | 0.5 | 1.08 ± 0.04 | 5883 ± 59 | 4.42 ± 0.06 | 0.05 ± 0.07 | 49 |
| HD 175679 | – | 37.3 ± 2.8 | 1366.8 ± 5.7 | 0.378 ± 0.008 | 2.7 ± 0.3 | 4844 ± 100 | 2.59 ± 0.10 | −0.14 ± 0.10 | 50 |
| HD 136118 | |$42^{+11}_{-18}$| | 12.0 ± 0.47 | 1188.0 ± 2.0 | 0.34 ± 0.01 | 1.24 ± 0.07 | 6097 ± 44 | 4.16 ± 0.09 | −0.01 ± 0.05 | 59, 60 |
| HD 217786 | – | 13.0 ± 0.8 | 1319 ± 4 | 0.40 ± 0.05 | 1.02 ± 0.03 | 5966 ± 65 | 4.35 ± 0.11 | −0.135 ± 0.043 | 61 |
| WASP-30 | 60.96 ± 0.89 | – | 4.156 736 ± 0.000 013 | 0 (adopted) | 1.17 ± 0.03 | 6201 ± 97 | 4.28 ± 0.01 | −0.03 ± 0.10 | 13 |
| COROT-15 | 63.3 ± 4.1 | – | 3.060 36 ± 0.000 03 | 0 (adopted) | 1.32 ± 0.12 | 6350 ± 200 | 4.3 ± 0.2 | 0.10 ± 0.20 | 14 |
| LHS 6343 | 62.9 ± 2.3 | – | 12.713 82 ± 0.000 04 | 0.056 ± 0.032 | 0.370 ± 0.009 | – | 4.851 ± 0.008 | 0.04 ± 0.08 | 15 |
| Corot-3b | 21.66 ± 1.00 | – | 4.256 80 ± 0.000 005 | 0 (adopted) | 1.37 ± 0.09 | 6740 ± 140 | 4.22 ± 0.07 | −0.02 ± 0.06 | 19 |
| XO-3b | 11.8 ± 0.59 | – | 3.191 5239 ± 0.000 0068 | 0.26 ± 0.017 | 1.213 ± 0.066 | 6429 ± 100 | 4.244 ± 0.041 | −0.177 ± 0.080 | 20 |
| KOI-423b | 18.0|$^{+0.93}_{-0.91}$| | – | 21.0874 ± 0.0002 | 0.121|$^{+0.022}_{-0.023}$| | 1.1|$^{+0.07}_{-0.06}$| | 6260 ± 140 | 4.1 ± 0.2 | −0.29 ± 0.10 | 23 |
| KELT-1b | 27.23|$^{+0.5}_{-0.48}$| | – | 1.217 514 ± 0.000 015 | 0.0099|$^{+0.01}_{-0.0069}$| | 1.324 ± 0.026 | 6518 ± 50 | 4.229|$^{+0.012}_{-0.019}$| | 0.008 ± 0.073 | 56 |
| KOI-554.01 | 80 | – | 3.66 | – | – | 5835 | 4.64 | −0.08 | 57 |
| KOI-205.01 | 39.9 ± 1.0 | – | 11.720 125 ± 0.000 002 | <0.031 | 0.925 ± 0.033 | 5237 ± 60 | 4.57 | 0.14 ± 0.12 | 64 |
References. 1 – Sahlmann et al. (2011b); 2 – Sato et al. (2010); 3 – Hatzes et al. (2005); 4 – Nidever et al. (2002); 5 – Benedict et al. (2010); 6 – Wittenmyer et al. (2009); 7 – Liu et al. (2008); 8 – Omiya et al. (2009); 9 – Moutou et al. (2009); 10 – Endl et al. (2004); 11 – Butler et al. (2006); 12 – Udry et al. (2002); 13 – Anderson et al. (2011); 14 – Bouchy et al. (2011a); 15 – Johnson et al. (2011); 16 – Lee et al. (2011); 17 – Halbwachs et al. (2000); 18 – Díaz et al. (2012); 19 – Deleuil et al. (2008); 20 – Winn et al. (2008); 21 – Ma et al. (2013); 22 – Marcy et al. (2001); 23 – Bouchy et al. (2011b); 24 – Galland et al. (2006); 25 – Gerbaldi, Faraggiana & Caffau (2007); 26 – Perrier et al. (2003); 27 – Jenkins et al. (2009); 28 – Correia et al. (2005); 29 – Feroz, Balan & Hobson (2011); 30 – Zucker et al. (2004); 31 – Winn et al. (2010); 32 – Niedzielski et al. (2009); 33 – Frink et al. (2002); 34 – Kane et al. (2011); 35 – Önehag et al. (2009); 36 – Lovis & Mayor (2007); 37 – Santos et al. (2009); 38 – Sato et al. (2009); 39 – Mugrauer et al. (2006); 40 – Vogt et al. (2000); 41 – Wittenmyer et al. (2009); 42 – Zucker & Mazeh (2000); 43 – Latham et al. (1989); 44 – Kane et al. (2009); 45 – Fleming et al. (2010); 46 – Lafrenière et al. (2011); 47 – Konopacky et al. (2010); 48 – Sahlmann et al. (2011b); 49 – Crepp et al. (2011); 50 – Wang et al. (2012); 51 – Patel et al. (2007); 52 – Lo Curto et al. (2010); 53 – Santos et al. (2010); 54 – Sozzetti et al. (2006); 55 – Siverd et al. (2012); 56 – Sozzetti & Desidera (2010); 57 – Santerne et al. (2012); 58 – Fleming et al. (2012); 59 – Fischer et al. (2002); 60 – Martioli et al. (2010); 61 – Moutou et al. (2011); 62 – Ma et al. (in preparation); 63 – Jiang, Ge & Cargile (2013) and 64 – Díaz et al. (2013).
Close BD (candidate) companions to solar-type stars.
| Object | Mc | Mc sin i | Period | Eccentricity | M⋆ | Teff | log (g) | [Fe/H] | References |
|---|---|---|---|---|---|---|---|---|---|
| (MJup) | (MJup) | (d) | (M⊙) | (K) | (cgs) | ||||
| HD 52756 | – | |$59.3^{+ 2.0}_{-1.9}$| | 52.8657 ± 0.0001 | 0.6780 ± 0.0003 | 0.83 ± 0.01 | 5216 ± 65 | 4.47 ± 0.11 | 0.13 ± 0.05 | 1 |
| HD 89707 | – | |$53.6^{+7.8}_{-6.9}$| | 298.5 ± 0.1 | 0.900|$^{+0.039}_{-0.035}$| | 0.96 ± 0.04 | 6047 ± 50 | 4.52 ± 0.10 | −0.33 ± 0.06 | 1 |
| HD 167665 | – | 50.6 ± 1.7 | 4451.8|$^{+27.6}_{-27.3}$| | 0.340 ± 0.005 | 1.14 ± 0.03 | 6224 ± 50 | 4.44 ± 0.10 | −0.05 ± 0.06 | 1 |
| HD 189310 | – | |$25.6^{+0.9}_{-0.8}$| | 14.186 43 ± 0.000 02 | 0.359 ± 0.001 | 0.83 ± 0.02 | 5188 ± 50 | 4.49 ± 0.10 | −0.01 ± 0.06 | 1 |
| HD 4747 | – | 46.1 ± 2.3 | 11 593.2|$^{+1118.6}_{-1117.6}$| | 0.723 ± 0.013 | 0.81 ± 0.02 | 5316 ± 50 | 4.48 ± 0.10 | −0.21 ± 0.05 | 1 |
| HD 211847 | – | 19.2 ± 1.2 | 7929.40|$^{+1999.1}_{-2500.2}$| | |$0.685^{+0.068}_{-0.067}$| | 0.94 ± 0.04 | 5715 ± 50 | 4.49 ± 0.10 | −0.08 ± 0.06 | 1 |
| HD 180314 | – | 22.0 | 396.03 ± 0.62 | 0.257 ± 0.010 | 2.6 ± 0.3 | 4917 ± 100 | 2.98 ± 0.12 | 0.2 ± 0.09 | 3 |
| HD 13189 | – | 20.0 | 471.6 ± 6.0 | 0.27 ± 0.06 | 7 | 5000 ± 100 | 2.0 ± 0.1 | 0.0 ± 0.10 | 4 |
| HD 30339 | – | 77.8 | 15.0778 ± 0.000 | 0.25 | 1.1 | 6074 ± 100 | 4.37 ± 0.10 | 0.21 ± 0.10 | 4 |
| HD 65430 | – | 67.8 | 3138 ± 342 | 0.32 | 0.78 | 5183 ± 100 | 4.55 ± 0.10 | −0.04 ± 0.10 | 4 |
| HD 140913 | – | 43.2 | 147.968 ± 0.000 | 0.54 | 0.98 | 6048 ± 100 | 4.57 ± 0.10 | 0.07 ± 0.10 | 4 |
| HD 38529c | 17.6|$^{+1.5}_{-1.2}$| | 13.99 ± 0.59 | 2136.14 ± 0.29 | 0.362 ± 0.002 | 1.48 ± 0.05 | 5697 | 3.94 ± 0.10 | +0.27 ± 0.05 | 5 |
| HD 91669 | – | 30.6 ± 2.1 | 497.5 ± 0.6 | 0.448 ± 0.002 | |$0.914^{+0.018}_{-0.087}$| | 5185 ± 87 | 4.48 ± 0.20 | +0.31 ± 0.08 | 6 |
| 11Com | – | 19.4 ± 1.5 | 326.03 ± 0.32 | 0.231 ± 0.005 | 2.7 ± 0.3 | 4742 ± 100 | 2.31 ± 0.10 | −0.35 ± 0.09 | 7 |
| HD 119445 | – | 37.6 ± 2.6 | 410.2 ± 0.6 | 0.082 ± 0.007 | 3.9 ± 0.4 | 5083 ± 103 | 2.40 ± 0.17 | 0.04 ± 0.18 | 8 |
| HD 131664 | |$23^{+26.0}_{-5.0}$| | – | 1951 ± 41 | 0.638 ± 0.02 | 1.10 ± 0.03 | 5886 ± 21 | 4.44 ± 0.10 | +0.32 ± 0.02 | 9, 56 |
| GJ 595 | – | 60.0 ± 0.0 | 62.6277 ± 0.0001 | 0.26 ± 0.001 | 0.28 | 3500 ± 100 | 4.83 ± 0.10 | 0.0 ± 0.10 | 4 |
| HD 162020 | – | 14.4 ± 0.04 | 8.428 198 ± 0.000 056 | 0.277 ± 0.002 | 0.75 | 4830 ± 80 | 4.76 ± 0.25 | +0.01 ± 0.11 | 12 |
| HD 168443 | 34.3 ± 9.0 | – | 1748.2 ± 1.0 | 0.2122 ± 0.0020 | 1.01 ± 0.05 | 5555 ± 40 | 4.10 ± 0.12 | +0.10 ± 0.03 | 1, 12, 22 |
| HD 180777 | – | 25.0 ± 0.0 | 28.44 ± 0.01 | 0.20 | 1.7 ± 0.1 | 7250 | 4.34 | −0.16 | 1, 24, 25 |
| HD 190228 | 49.4 ± 14.8 | – | 1146 ± 16 | 0.50 ± 0.04 | 0.83 | 5360 ± 40 | 4.02 ± 0.10 | −0.24 ± 0.06 | 1, 26 |
| HD 191760 | – | 38.17 ± 1.02 | 505.65 ± 0.42 | 0.63 ± 0.01 | 1.28|$^{+0.02}_{-0.10}$| | 5821 ± 82 | 4.13|$^{+0.05}_{-0.04}$| | 0.29 ± 0.07 | 1, 27 |
| HD 202206 | – | 17.5 | 256.20 ± 0.03 | 0.433 ± 0.001 | 1.15 | 5765 ± 40 | 4.75 ± 0.20 | 0.37 ± 0.07 | 1, 12, 28 |
| HIP 21832 | 40.9 ± 26.2 | – | 1474.9 ± 10.2 | 0.356 ± 0.095 | 1.0 ± 0.0 | 5554 ± 70 | 4.32 ± 0.10 | −0.63 ± 0.10 | 17 |
| HD 14651 | – | 47.0 ± 3.4 | 79.4179 ± 0.0021 | 0.4751 ± 0.0010 | 0.96 ± 0.03 | 5491 ± 26 | 4.45 ± 0.03 | −0.04 ± 0.06 | 18 |
| HD 30246 | – | 55.1|$^{+20.3}_{-8.2}$| | 990.7 ± 5.6 | 0.838 ± 0.081 | 1.05 ± 0.04 | 5833 ± 44 | 4.39 ± 0.04 | +0.17 ± 0.10 | 18 |
| HD 92320 | – | 59.4 ± 4.1 | 145.4 ± 0.01 | 0.323 | 0.92 ± 0.04 | 5664 ± 24 | 4.48 ± 0.03 | −0.10 ± 0.06 | 18 |
| HD 22781 | – | 13.65 ± 0.97 | 528.07 ± 0.14 | 0.8191 ± 0.0023 | 0.75 ± 0.03 | 5027 ± 50 | 4.60 ± 0.02 | −0.37 ± 0.12 | 18 |
| HD 137510 | 20.0–60.0 | 27.3 ± 1.9 | 801.30 ± 0.45 | 0.3985 ± 0.0073 | 1.36 ± 0.04 | 6131 ± 50 | 4.02 ± 0.04 | 0.38 ± 0.13 | 10, 11, 18, |
| HIP 5158 | – | 15.04 ± 10.55 | 9017.76 ± 3180.74 | 0.14 ± 0.10 | 0.780 ± 0.021 | 4962 ± 89 | 4.37 ± 0.20 | 0.10 ± 0.07 | 29, 52 |
| HD 41004B | – | 18.37 ± 0.22 | 1.328 300 ± 0.000 012 | 0.081 ± 0.012 | 0.40 ± 0.04 | – | – | – | 30 |
| HAT-P-13c | – | 14.28 ± 0.28 | 446.27 ± 0.22 | 0.6616 ± 0.0054 | 1.22|$^{+0.05}_{-0.10}$| | 5640 ± 90 | 4.13 ± 0.04 | 0.430 ± 0.08 | 31 |
| BD+202457b | – | 22.7 ± 8.1 | 379.63 ± 2.01 | 0.15 ± 0.03 | 2.8 ± 1.5 | 4137 ± 10 | 1.51 ± 0.05 | −1.00 ± 0.07 | 32 |
| BD+202457c | – | 13.2 ± 4.7 | 621.99 ± 10.20 | 0.18 ± 0.06 | 2.8 ± 1.5 | 4137 ± 10 | 1.51 ± 0.05 | −1.00 ± 0.07 | 32 |
| HD 137759 | – | 12.7 ± 1.08 | 511.098 ± 0.089 | 0.7124 ± 0.0039 | 1.80 ± 0.23 | 4500 ± 110 | 2.74 ± 0.10 | 0.03 ± 0.10 | 11, 33, 35 |
| NGC 2423−3b | – | 10.64 ± 0.93 | 714.3 ± 5.3 | 0.21 ± 0.07 | 2.4 ± 0.2 | – | – | – | 36, 37 |
| NGC 4349−127b | – | 20.0 ± 1.73 | 678.0 ± 6.2 | 0.19 | 3.9 ± 0.3 | 4569 ± 69 | 2.08 ± 0.35 | −0.13 ± 0.18 | 36, 37 |
| HD 16760b | – | 13.13 ± 0.56 | 466.47 ± 0.35 | 0.084 ± 0.003 | 0.78 ± 0.05 | 5629 ± 44 | 4.47 ± 0.06 | +0.067 ± 0.05 | 38 |
| HD 10697 | 38 ± 13 | – | 1075.0 ± 1.5 | 0.099 ± 0.007 | 1.112|$^{+0.026}_{-0.02}$| | 5680 ± 44 | 4.12 ± 0.06 | 0.19 ± 0.03 | 40, 41, 42 |
| HD 114762 | – | 10.99 ± 0.09 | 83.9152 ± 0.0028 | 0.3325 | 0.89 ± 0.09 | 5950 ± 44 | 4.54 ± 0.06 | −0.65 ± 0.03 | 11, 34, 43 |
| TYC 2534-698-1 | – | 39.1 ± 11.5 | 103.698 ± 0.111 000 | 0.385 | 0.998 ± 0.040 | 5700 ± 80 | 4.50 ± 0.10 | −0.25 ± 0.06 | 44 |
| TYC 2949-557-1 | – | 64.3 ± 3.0 | 5.694 49 ± 0.000 29 | 0.0017|$^{+0.0019}_{-0.0017}$| | 1.25 ± 0.09 | 6135 ± 40 | 4.4 ± 0.1 | 0.32 ± 0.01 | 45 |
| TYC 1240-945-1 | – | 28.0 ± 1.5 | 5.8953 ± 0.0004 | 0.015 ± 0.011 | 1.37 ± 0.11 | 6186 ± 92 | 3.89 ± 0.07 | −0.15 ± 0.04 | 16 |
| HIP 67526 | – | 62.6 ± 0.6 | 90.2695 ± 0.0188 | 0.4375 ± 0.0040 | 1.11 ± 0.08 | 6004 ± 29 | 4.55 ± 0.15 | 0.04 ± 0.05 | 63 |
| TYC 2930-872-1 | – | 68.1 ± 3.0 | 2.430 420 ± 0.000 006 | 0.0066 ± 0.0010 | 1.21 ± 0.08 | 6427 ± 33 | 4.52 ± 0.14 | −0.04 ± 0.05 | 58 |
| TYC 2087-255-1 | – | 40.0 ± 1.8 | 9.0090 ± 0.0004 | 0.226 ± 0.011 | 1.16 ± 0.08 | 5903 ± 42 | 4.07 ± 0.16 | −0.23 ± 0.07 | 21 |
| TYC 3130-160 | – | 57.4 ± 3.0 | 31.66 ± 0.023 | 0.688 | 1.0 ± 0.1 | 5104 ± 50 | 4.43 ± 0.10 | 0.01 ± 0.05 | 62 |
| HIP 78530 | – | 23 ± 3 | ∼4.38 × 106 | 0 (fixed) | 2.5 ± 0.2 | 10500 ± 500 | – | – | 46 |
| HD 5388b | 69.2 ± 19.9 | – | 777.0 ± 4.0 | 0.40 ± 0.02 | 1.21 ± 0.10 | 6297 ± 32 | 4.28 ± 0.06 | −0.27 ± 0.02 | 48, 53 |
| HR 7672b | 68.7 ± 3.0 | – | 26 772|$^{+803.5}_{-1059.2}$| | 0.5 | 1.08 ± 0.04 | 5883 ± 59 | 4.42 ± 0.06 | 0.05 ± 0.07 | 49 |
| HD 175679 | – | 37.3 ± 2.8 | 1366.8 ± 5.7 | 0.378 ± 0.008 | 2.7 ± 0.3 | 4844 ± 100 | 2.59 ± 0.10 | −0.14 ± 0.10 | 50 |
| HD 136118 | |$42^{+11}_{-18}$| | 12.0 ± 0.47 | 1188.0 ± 2.0 | 0.34 ± 0.01 | 1.24 ± 0.07 | 6097 ± 44 | 4.16 ± 0.09 | −0.01 ± 0.05 | 59, 60 |
| HD 217786 | – | 13.0 ± 0.8 | 1319 ± 4 | 0.40 ± 0.05 | 1.02 ± 0.03 | 5966 ± 65 | 4.35 ± 0.11 | −0.135 ± 0.043 | 61 |
| WASP-30 | 60.96 ± 0.89 | – | 4.156 736 ± 0.000 013 | 0 (adopted) | 1.17 ± 0.03 | 6201 ± 97 | 4.28 ± 0.01 | −0.03 ± 0.10 | 13 |
| COROT-15 | 63.3 ± 4.1 | – | 3.060 36 ± 0.000 03 | 0 (adopted) | 1.32 ± 0.12 | 6350 ± 200 | 4.3 ± 0.2 | 0.10 ± 0.20 | 14 |
| LHS 6343 | 62.9 ± 2.3 | – | 12.713 82 ± 0.000 04 | 0.056 ± 0.032 | 0.370 ± 0.009 | – | 4.851 ± 0.008 | 0.04 ± 0.08 | 15 |
| Corot-3b | 21.66 ± 1.00 | – | 4.256 80 ± 0.000 005 | 0 (adopted) | 1.37 ± 0.09 | 6740 ± 140 | 4.22 ± 0.07 | −0.02 ± 0.06 | 19 |
| XO-3b | 11.8 ± 0.59 | – | 3.191 5239 ± 0.000 0068 | 0.26 ± 0.017 | 1.213 ± 0.066 | 6429 ± 100 | 4.244 ± 0.041 | −0.177 ± 0.080 | 20 |
| KOI-423b | 18.0|$^{+0.93}_{-0.91}$| | – | 21.0874 ± 0.0002 | 0.121|$^{+0.022}_{-0.023}$| | 1.1|$^{+0.07}_{-0.06}$| | 6260 ± 140 | 4.1 ± 0.2 | −0.29 ± 0.10 | 23 |
| KELT-1b | 27.23|$^{+0.5}_{-0.48}$| | – | 1.217 514 ± 0.000 015 | 0.0099|$^{+0.01}_{-0.0069}$| | 1.324 ± 0.026 | 6518 ± 50 | 4.229|$^{+0.012}_{-0.019}$| | 0.008 ± 0.073 | 56 |
| KOI-554.01 | 80 | – | 3.66 | – | – | 5835 | 4.64 | −0.08 | 57 |
| KOI-205.01 | 39.9 ± 1.0 | – | 11.720 125 ± 0.000 002 | <0.031 | 0.925 ± 0.033 | 5237 ± 60 | 4.57 | 0.14 ± 0.12 | 64 |
| Object | Mc | Mc sin i | Period | Eccentricity | M⋆ | Teff | log (g) | [Fe/H] | References |
|---|---|---|---|---|---|---|---|---|---|
| (MJup) | (MJup) | (d) | (M⊙) | (K) | (cgs) | ||||
| HD 52756 | – | |$59.3^{+ 2.0}_{-1.9}$| | 52.8657 ± 0.0001 | 0.6780 ± 0.0003 | 0.83 ± 0.01 | 5216 ± 65 | 4.47 ± 0.11 | 0.13 ± 0.05 | 1 |
| HD 89707 | – | |$53.6^{+7.8}_{-6.9}$| | 298.5 ± 0.1 | 0.900|$^{+0.039}_{-0.035}$| | 0.96 ± 0.04 | 6047 ± 50 | 4.52 ± 0.10 | −0.33 ± 0.06 | 1 |
| HD 167665 | – | 50.6 ± 1.7 | 4451.8|$^{+27.6}_{-27.3}$| | 0.340 ± 0.005 | 1.14 ± 0.03 | 6224 ± 50 | 4.44 ± 0.10 | −0.05 ± 0.06 | 1 |
| HD 189310 | – | |$25.6^{+0.9}_{-0.8}$| | 14.186 43 ± 0.000 02 | 0.359 ± 0.001 | 0.83 ± 0.02 | 5188 ± 50 | 4.49 ± 0.10 | −0.01 ± 0.06 | 1 |
| HD 4747 | – | 46.1 ± 2.3 | 11 593.2|$^{+1118.6}_{-1117.6}$| | 0.723 ± 0.013 | 0.81 ± 0.02 | 5316 ± 50 | 4.48 ± 0.10 | −0.21 ± 0.05 | 1 |
| HD 211847 | – | 19.2 ± 1.2 | 7929.40|$^{+1999.1}_{-2500.2}$| | |$0.685^{+0.068}_{-0.067}$| | 0.94 ± 0.04 | 5715 ± 50 | 4.49 ± 0.10 | −0.08 ± 0.06 | 1 |
| HD 180314 | – | 22.0 | 396.03 ± 0.62 | 0.257 ± 0.010 | 2.6 ± 0.3 | 4917 ± 100 | 2.98 ± 0.12 | 0.2 ± 0.09 | 3 |
| HD 13189 | – | 20.0 | 471.6 ± 6.0 | 0.27 ± 0.06 | 7 | 5000 ± 100 | 2.0 ± 0.1 | 0.0 ± 0.10 | 4 |
| HD 30339 | – | 77.8 | 15.0778 ± 0.000 | 0.25 | 1.1 | 6074 ± 100 | 4.37 ± 0.10 | 0.21 ± 0.10 | 4 |
| HD 65430 | – | 67.8 | 3138 ± 342 | 0.32 | 0.78 | 5183 ± 100 | 4.55 ± 0.10 | −0.04 ± 0.10 | 4 |
| HD 140913 | – | 43.2 | 147.968 ± 0.000 | 0.54 | 0.98 | 6048 ± 100 | 4.57 ± 0.10 | 0.07 ± 0.10 | 4 |
| HD 38529c | 17.6|$^{+1.5}_{-1.2}$| | 13.99 ± 0.59 | 2136.14 ± 0.29 | 0.362 ± 0.002 | 1.48 ± 0.05 | 5697 | 3.94 ± 0.10 | +0.27 ± 0.05 | 5 |
| HD 91669 | – | 30.6 ± 2.1 | 497.5 ± 0.6 | 0.448 ± 0.002 | |$0.914^{+0.018}_{-0.087}$| | 5185 ± 87 | 4.48 ± 0.20 | +0.31 ± 0.08 | 6 |
| 11Com | – | 19.4 ± 1.5 | 326.03 ± 0.32 | 0.231 ± 0.005 | 2.7 ± 0.3 | 4742 ± 100 | 2.31 ± 0.10 | −0.35 ± 0.09 | 7 |
| HD 119445 | – | 37.6 ± 2.6 | 410.2 ± 0.6 | 0.082 ± 0.007 | 3.9 ± 0.4 | 5083 ± 103 | 2.40 ± 0.17 | 0.04 ± 0.18 | 8 |
| HD 131664 | |$23^{+26.0}_{-5.0}$| | – | 1951 ± 41 | 0.638 ± 0.02 | 1.10 ± 0.03 | 5886 ± 21 | 4.44 ± 0.10 | +0.32 ± 0.02 | 9, 56 |
| GJ 595 | – | 60.0 ± 0.0 | 62.6277 ± 0.0001 | 0.26 ± 0.001 | 0.28 | 3500 ± 100 | 4.83 ± 0.10 | 0.0 ± 0.10 | 4 |
| HD 162020 | – | 14.4 ± 0.04 | 8.428 198 ± 0.000 056 | 0.277 ± 0.002 | 0.75 | 4830 ± 80 | 4.76 ± 0.25 | +0.01 ± 0.11 | 12 |
| HD 168443 | 34.3 ± 9.0 | – | 1748.2 ± 1.0 | 0.2122 ± 0.0020 | 1.01 ± 0.05 | 5555 ± 40 | 4.10 ± 0.12 | +0.10 ± 0.03 | 1, 12, 22 |
| HD 180777 | – | 25.0 ± 0.0 | 28.44 ± 0.01 | 0.20 | 1.7 ± 0.1 | 7250 | 4.34 | −0.16 | 1, 24, 25 |
| HD 190228 | 49.4 ± 14.8 | – | 1146 ± 16 | 0.50 ± 0.04 | 0.83 | 5360 ± 40 | 4.02 ± 0.10 | −0.24 ± 0.06 | 1, 26 |
| HD 191760 | – | 38.17 ± 1.02 | 505.65 ± 0.42 | 0.63 ± 0.01 | 1.28|$^{+0.02}_{-0.10}$| | 5821 ± 82 | 4.13|$^{+0.05}_{-0.04}$| | 0.29 ± 0.07 | 1, 27 |
| HD 202206 | – | 17.5 | 256.20 ± 0.03 | 0.433 ± 0.001 | 1.15 | 5765 ± 40 | 4.75 ± 0.20 | 0.37 ± 0.07 | 1, 12, 28 |
| HIP 21832 | 40.9 ± 26.2 | – | 1474.9 ± 10.2 | 0.356 ± 0.095 | 1.0 ± 0.0 | 5554 ± 70 | 4.32 ± 0.10 | −0.63 ± 0.10 | 17 |
| HD 14651 | – | 47.0 ± 3.4 | 79.4179 ± 0.0021 | 0.4751 ± 0.0010 | 0.96 ± 0.03 | 5491 ± 26 | 4.45 ± 0.03 | −0.04 ± 0.06 | 18 |
| HD 30246 | – | 55.1|$^{+20.3}_{-8.2}$| | 990.7 ± 5.6 | 0.838 ± 0.081 | 1.05 ± 0.04 | 5833 ± 44 | 4.39 ± 0.04 | +0.17 ± 0.10 | 18 |
| HD 92320 | – | 59.4 ± 4.1 | 145.4 ± 0.01 | 0.323 | 0.92 ± 0.04 | 5664 ± 24 | 4.48 ± 0.03 | −0.10 ± 0.06 | 18 |
| HD 22781 | – | 13.65 ± 0.97 | 528.07 ± 0.14 | 0.8191 ± 0.0023 | 0.75 ± 0.03 | 5027 ± 50 | 4.60 ± 0.02 | −0.37 ± 0.12 | 18 |
| HD 137510 | 20.0–60.0 | 27.3 ± 1.9 | 801.30 ± 0.45 | 0.3985 ± 0.0073 | 1.36 ± 0.04 | 6131 ± 50 | 4.02 ± 0.04 | 0.38 ± 0.13 | 10, 11, 18, |
| HIP 5158 | – | 15.04 ± 10.55 | 9017.76 ± 3180.74 | 0.14 ± 0.10 | 0.780 ± 0.021 | 4962 ± 89 | 4.37 ± 0.20 | 0.10 ± 0.07 | 29, 52 |
| HD 41004B | – | 18.37 ± 0.22 | 1.328 300 ± 0.000 012 | 0.081 ± 0.012 | 0.40 ± 0.04 | – | – | – | 30 |
| HAT-P-13c | – | 14.28 ± 0.28 | 446.27 ± 0.22 | 0.6616 ± 0.0054 | 1.22|$^{+0.05}_{-0.10}$| | 5640 ± 90 | 4.13 ± 0.04 | 0.430 ± 0.08 | 31 |
| BD+202457b | – | 22.7 ± 8.1 | 379.63 ± 2.01 | 0.15 ± 0.03 | 2.8 ± 1.5 | 4137 ± 10 | 1.51 ± 0.05 | −1.00 ± 0.07 | 32 |
| BD+202457c | – | 13.2 ± 4.7 | 621.99 ± 10.20 | 0.18 ± 0.06 | 2.8 ± 1.5 | 4137 ± 10 | 1.51 ± 0.05 | −1.00 ± 0.07 | 32 |
| HD 137759 | – | 12.7 ± 1.08 | 511.098 ± 0.089 | 0.7124 ± 0.0039 | 1.80 ± 0.23 | 4500 ± 110 | 2.74 ± 0.10 | 0.03 ± 0.10 | 11, 33, 35 |
| NGC 2423−3b | – | 10.64 ± 0.93 | 714.3 ± 5.3 | 0.21 ± 0.07 | 2.4 ± 0.2 | – | – | – | 36, 37 |
| NGC 4349−127b | – | 20.0 ± 1.73 | 678.0 ± 6.2 | 0.19 | 3.9 ± 0.3 | 4569 ± 69 | 2.08 ± 0.35 | −0.13 ± 0.18 | 36, 37 |
| HD 16760b | – | 13.13 ± 0.56 | 466.47 ± 0.35 | 0.084 ± 0.003 | 0.78 ± 0.05 | 5629 ± 44 | 4.47 ± 0.06 | +0.067 ± 0.05 | 38 |
| HD 10697 | 38 ± 13 | – | 1075.0 ± 1.5 | 0.099 ± 0.007 | 1.112|$^{+0.026}_{-0.02}$| | 5680 ± 44 | 4.12 ± 0.06 | 0.19 ± 0.03 | 40, 41, 42 |
| HD 114762 | – | 10.99 ± 0.09 | 83.9152 ± 0.0028 | 0.3325 | 0.89 ± 0.09 | 5950 ± 44 | 4.54 ± 0.06 | −0.65 ± 0.03 | 11, 34, 43 |
| TYC 2534-698-1 | – | 39.1 ± 11.5 | 103.698 ± 0.111 000 | 0.385 | 0.998 ± 0.040 | 5700 ± 80 | 4.50 ± 0.10 | −0.25 ± 0.06 | 44 |
| TYC 2949-557-1 | – | 64.3 ± 3.0 | 5.694 49 ± 0.000 29 | 0.0017|$^{+0.0019}_{-0.0017}$| | 1.25 ± 0.09 | 6135 ± 40 | 4.4 ± 0.1 | 0.32 ± 0.01 | 45 |
| TYC 1240-945-1 | – | 28.0 ± 1.5 | 5.8953 ± 0.0004 | 0.015 ± 0.011 | 1.37 ± 0.11 | 6186 ± 92 | 3.89 ± 0.07 | −0.15 ± 0.04 | 16 |
| HIP 67526 | – | 62.6 ± 0.6 | 90.2695 ± 0.0188 | 0.4375 ± 0.0040 | 1.11 ± 0.08 | 6004 ± 29 | 4.55 ± 0.15 | 0.04 ± 0.05 | 63 |
| TYC 2930-872-1 | – | 68.1 ± 3.0 | 2.430 420 ± 0.000 006 | 0.0066 ± 0.0010 | 1.21 ± 0.08 | 6427 ± 33 | 4.52 ± 0.14 | −0.04 ± 0.05 | 58 |
| TYC 2087-255-1 | – | 40.0 ± 1.8 | 9.0090 ± 0.0004 | 0.226 ± 0.011 | 1.16 ± 0.08 | 5903 ± 42 | 4.07 ± 0.16 | −0.23 ± 0.07 | 21 |
| TYC 3130-160 | – | 57.4 ± 3.0 | 31.66 ± 0.023 | 0.688 | 1.0 ± 0.1 | 5104 ± 50 | 4.43 ± 0.10 | 0.01 ± 0.05 | 62 |
| HIP 78530 | – | 23 ± 3 | ∼4.38 × 106 | 0 (fixed) | 2.5 ± 0.2 | 10500 ± 500 | – | – | 46 |
| HD 5388b | 69.2 ± 19.9 | – | 777.0 ± 4.0 | 0.40 ± 0.02 | 1.21 ± 0.10 | 6297 ± 32 | 4.28 ± 0.06 | −0.27 ± 0.02 | 48, 53 |
| HR 7672b | 68.7 ± 3.0 | – | 26 772|$^{+803.5}_{-1059.2}$| | 0.5 | 1.08 ± 0.04 | 5883 ± 59 | 4.42 ± 0.06 | 0.05 ± 0.07 | 49 |
| HD 175679 | – | 37.3 ± 2.8 | 1366.8 ± 5.7 | 0.378 ± 0.008 | 2.7 ± 0.3 | 4844 ± 100 | 2.59 ± 0.10 | −0.14 ± 0.10 | 50 |
| HD 136118 | |$42^{+11}_{-18}$| | 12.0 ± 0.47 | 1188.0 ± 2.0 | 0.34 ± 0.01 | 1.24 ± 0.07 | 6097 ± 44 | 4.16 ± 0.09 | −0.01 ± 0.05 | 59, 60 |
| HD 217786 | – | 13.0 ± 0.8 | 1319 ± 4 | 0.40 ± 0.05 | 1.02 ± 0.03 | 5966 ± 65 | 4.35 ± 0.11 | −0.135 ± 0.043 | 61 |
| WASP-30 | 60.96 ± 0.89 | – | 4.156 736 ± 0.000 013 | 0 (adopted) | 1.17 ± 0.03 | 6201 ± 97 | 4.28 ± 0.01 | −0.03 ± 0.10 | 13 |
| COROT-15 | 63.3 ± 4.1 | – | 3.060 36 ± 0.000 03 | 0 (adopted) | 1.32 ± 0.12 | 6350 ± 200 | 4.3 ± 0.2 | 0.10 ± 0.20 | 14 |
| LHS 6343 | 62.9 ± 2.3 | – | 12.713 82 ± 0.000 04 | 0.056 ± 0.032 | 0.370 ± 0.009 | – | 4.851 ± 0.008 | 0.04 ± 0.08 | 15 |
| Corot-3b | 21.66 ± 1.00 | – | 4.256 80 ± 0.000 005 | 0 (adopted) | 1.37 ± 0.09 | 6740 ± 140 | 4.22 ± 0.07 | −0.02 ± 0.06 | 19 |
| XO-3b | 11.8 ± 0.59 | – | 3.191 5239 ± 0.000 0068 | 0.26 ± 0.017 | 1.213 ± 0.066 | 6429 ± 100 | 4.244 ± 0.041 | −0.177 ± 0.080 | 20 |
| KOI-423b | 18.0|$^{+0.93}_{-0.91}$| | – | 21.0874 ± 0.0002 | 0.121|$^{+0.022}_{-0.023}$| | 1.1|$^{+0.07}_{-0.06}$| | 6260 ± 140 | 4.1 ± 0.2 | −0.29 ± 0.10 | 23 |
| KELT-1b | 27.23|$^{+0.5}_{-0.48}$| | – | 1.217 514 ± 0.000 015 | 0.0099|$^{+0.01}_{-0.0069}$| | 1.324 ± 0.026 | 6518 ± 50 | 4.229|$^{+0.012}_{-0.019}$| | 0.008 ± 0.073 | 56 |
| KOI-554.01 | 80 | – | 3.66 | – | – | 5835 | 4.64 | −0.08 | 57 |
| KOI-205.01 | 39.9 ± 1.0 | – | 11.720 125 ± 0.000 002 | <0.031 | 0.925 ± 0.033 | 5237 ± 60 | 4.57 | 0.14 ± 0.12 | 64 |
References. 1 – Sahlmann et al. (2011b); 2 – Sato et al. (2010); 3 – Hatzes et al. (2005); 4 – Nidever et al. (2002); 5 – Benedict et al. (2010); 6 – Wittenmyer et al. (2009); 7 – Liu et al. (2008); 8 – Omiya et al. (2009); 9 – Moutou et al. (2009); 10 – Endl et al. (2004); 11 – Butler et al. (2006); 12 – Udry et al. (2002); 13 – Anderson et al. (2011); 14 – Bouchy et al. (2011a); 15 – Johnson et al. (2011); 16 – Lee et al. (2011); 17 – Halbwachs et al. (2000); 18 – Díaz et al. (2012); 19 – Deleuil et al. (2008); 20 – Winn et al. (2008); 21 – Ma et al. (2013); 22 – Marcy et al. (2001); 23 – Bouchy et al. (2011b); 24 – Galland et al. (2006); 25 – Gerbaldi, Faraggiana & Caffau (2007); 26 – Perrier et al. (2003); 27 – Jenkins et al. (2009); 28 – Correia et al. (2005); 29 – Feroz, Balan & Hobson (2011); 30 – Zucker et al. (2004); 31 – Winn et al. (2010); 32 – Niedzielski et al. (2009); 33 – Frink et al. (2002); 34 – Kane et al. (2011); 35 – Önehag et al. (2009); 36 – Lovis & Mayor (2007); 37 – Santos et al. (2009); 38 – Sato et al. (2009); 39 – Mugrauer et al. (2006); 40 – Vogt et al. (2000); 41 – Wittenmyer et al. (2009); 42 – Zucker & Mazeh (2000); 43 – Latham et al. (1989); 44 – Kane et al. (2009); 45 – Fleming et al. (2010); 46 – Lafrenière et al. (2011); 47 – Konopacky et al. (2010); 48 – Sahlmann et al. (2011b); 49 – Crepp et al. (2011); 50 – Wang et al. (2012); 51 – Patel et al. (2007); 52 – Lo Curto et al. (2010); 53 – Santos et al. (2010); 54 – Sozzetti et al. (2006); 55 – Siverd et al. (2012); 56 – Sozzetti & Desidera (2010); 57 – Santerne et al. (2012); 58 – Fleming et al. (2012); 59 – Fischer et al. (2002); 60 – Martioli et al. (2010); 61 – Moutou et al. (2011); 62 – Ma et al. (in preparation); 63 – Jiang, Ge & Cargile (2013) and 64 – Díaz et al. (2013).
3 OBSERVED PROPERTIES OF BROWN DWARFS
3.1 Orbital period distribution
The distribution of orbital periods of BDs has two main features (Fig. 1): a relatively flat distribution inside P ∼ 100 d and a sharp jump beyond P ∼ 100 d. The drop beyond P ∼ 1000 d is likely due to the observational incompleteness since (1) it is more difficult to detect a BD companion over a long period than a short period with RVs and (2) some RV surveys (such as the SDSS-III MARVELS; Ge et al. 2008, 2009; Eisenstein et al. 2011) do not cover beyond this period. It is evident that the number of BDs increases with the orbital period, even though RV and transit observations are biased towards discovering objects in short periods. The position of the maximum of the distribution is unknown due to the different duration limit of most of the old surveys (several thousand days). This increasing distribution is consistent with the results from high-contrast and high-angular-resolution imaging surveys, which find evidence for a higher fraction of BD companions at wide orbits than at close orbits (Lafrenière et al. 2007; Metchev & Hillenbrand 2009; Chauvin et al. 2010; Janson et al. 2012).
Period distribution of known BD companions around solar-type stars.
For comparison, both extrasolar giant planets (Cumming, Marcy & Butler 1999; Udry, Mayor & Santos 2003; Marcy et al. 2005; Udry & Santos 2007) and binaries (Duquennoy & Mayor 1991) show an increasing number distribution with period. However, there is no 3 d pile up with the BD distribution as shown in giant planets (Udry et al. 2003). The reason may be that BDs initially form in the protoplanetary discs further away from the host stars where protoplanetary discs have more materials to efficiently form BDs than at the close-in regions, and the migration mechanism may not efficiently move such a massive body to a short-period orbit (Trilling et al. 1998; Nelson et al. 2000; Trilling, Lunine & Benz 2002). On the other hand, BDs forming at the same time as the primary stars may migrate inwards quickly in the initial gas-rich discs and thus be destroyed via mergers with the stars (Armitage & Bonnell 2002).
3.2 The period–mass diagram
The period–mass distribution of BDs shows a statistically significant gap at the short-period and medium-mass region as illustrated in Fig. 2. In this plot, a rectangular area with P < 100 d and 35 < M < 55MJup is highlighted to show the gap within which BDs are nearly depleted, while there are numerous BDs around this region. It appears that this gap is real since it is unlikely caused by detection sensitivity (RV precision) or observation biases (due to survey incompleteness). Previous RV observations have detected many BDs with masses less than the lower limit (∼35MJup) of this region and also BDs with periods significantly longer than the period limit of this region (∼100 d). RV sensitivities with three moderate RV precisions, 50, 100 and 150 m s−1, shown in Fig. 2, clearly illustrate that any of the BDs in the gap should be detected easily with these moderate RV precisions. To further verify if this feature is real, we divided the BD sample into two groups according to their periods (P < 100 and >100 d) and plotted their mass cumulative histograms in Fig. 3 for comparison. It is apparent that a depletion of BDs with masses between 35 and 55MJup appears in the cumulative histogram for the short-period group, while no depletion of BDs appears in the cumulative histogram for the long-period group. We carried out a simple Monte Carlo experiment to test the emptiness of this gap on the period–mass diagram. There are a total of 25 BDs with period shorter than 100 d in our BD sample. We assumed simply that their masses are uniformly distributed between 13 and 80MJup. Then, we drew their masses randomly from this uniform distribution and counted how many of them would fall in the mass range 35–55MJup. We found the probability that less than three BDs would fall in this gap is 0.9 per cent, which corresponds to a 2.6σ significance. A larger BD sample in the future will be better to assess the significance of this gap.
Cumulative mass distribution of BD candidates. Three lines with three RV precisions, 50, 100 and 150 m s−1, are also shown.
Cumulative mass distribution of BD companions. BD with periods greater and less than 100 d are shown as dashed and solid lines, respectively.
The appearance of this depleted region in the BD period–mass diagram has naturally divided BDs into two mass groups: one with (minimum) masses greater than 42.5MJup and the other with less than 42.5MJup. Their properties and origins may be different. We further explore properties of these two groups and study possible origins.
3.3 Orbital eccentricity distribution
The orbital eccentricities show great difference for the two BD groups with (minimum) masses greater and lower than 42.5MJup, respectively. Fig. 4 shows the period–eccentricity distribution of all known BDs. The period–eccentricity distribution of BDs with (minimum) masses greater than 42.5MJup is consistent with a circularization limit of ∼12 d, which is similar to that found in nearby stellar binaries (Raghavan et al. 2010). It is clear that there are a significant number of BDs with 300 < P < 3000 d and e < 0.4 for BDs with (minimum) masses lower than 42.5MJup, but no BDs with (minimum) masses greater than 42.5MJup. A two-dimensional Kolmogorov–Smirnov (K-S) test for the period–eccentricity distribution of BDs with (minimum) masses greater and lower than 42.5MJup shows the probability that these two BD samples are drawn from the same distribution in the period–eccentricity plane is 1.7 per cent.
Period–eccentricity distribution of BD candidates. BD candidates with (minimum) masses above and below 42.5MJup are shown as circles and diamonds. BD candidates with true masses measured using transiting observations or astrometry measurements are shown as crosses.
Next, the period–eccentricity distribution of the BDs is compared to that of stellar binaries. Halbwachs et al. (2003) have studied the statistical properties of a sample of 89 FGK-type main-sequence binaries with periods up to 10 year. Here, we choose to use their 89 binary sample for our comparison. To compare the period–eccentricity distribution between BDs and stellar binaries, we made use of a two-dimensional K-S test. The probability for the period–eccentricity distribution to be the same is 18 per cent between BDs with (minimum) masses above 42.5MJup and the stellar binary sample, and 0.1 per cent between BDs with (minimum) masses below 42.5MJup and the stellar binary sample. These results suggest that BDs with (minimum) masses greater than 42.5MJup have a similar period–eccentricity distribution to that of stellar binaries, and their formation mechanisms may be similar.
The difference of the orbital eccentricities for BDs with different masses is further illustrated in the mass–eccentricity plot shown in Fig. 5. By including all currently known planets (from exoplanet.org) and BD (this paper) in this plot, a clear trend is shown: all the known giant planets and BDs with (minimum) masses below ∼42.5MJup have the eccentricity distribution following a trend, i.e. the more massive the giant planet/BD is, the lower maximum eccentricity it tends to have, while BDs above this mass threshold do not show such a trend, instead showing more diversity in their eccentricities. This trend is consistent with the picture that if the less massive (<42.5MJup) BDs are initially formed in a protoplanetary disc (whether through core-accretion or disc-instability model) and later pumped to higher eccentricities through scattering with other objects formed in the disc. This is because in such a scattering model (Chatterjee et al. 2008; Ford & Rasio 2008), the higher mass the BD has, the harder it is to pump it to a higher eccentricity. To illustrate this scattering model, two curves are overplotted in Fig. 5 to show what eccentricities will the BDs have if they are scattered by a 20 and 25MJup object. These two curves are calculated using a fitting formula from Ford & Rasio (2008) to cover the upper profile of the BDs eccentricity distribution. The need of a 20 or 25MJup object seems a little bit large because in the core-accretion model it is very difficult to form two such massive BDs and for one to be scattered away by the other one. However, it is still possible to form such a system in the disc-instability model (Forgan & Rice 2013).
Mass–eccentricity distribution of exoplanets and BD candidates. Two solid curves show prediction of BD eccentricity distribution after scattering with another object of mass 20 and 25MJup, respectively (from bottom to top). These curves are calculated using a fitting formula of planet–planet scattering model from Ford & Rasio (2008), which fit the BD eccentricity upper profile. The vertical dotted line shows M sin i = 42.5MJup. Planets are shown as squares. BD with masses above and below 42.5MJup are shown as triangles and circles, respectively.
3.4 Metallicity of the BD host stars
The BD host stars in this study have a mean metallicity of [Fe/H] = −0.04 with a standard deviation of 0.28. For comparison, Raghavan et al. (2010) has carefully studied a sample of 454 nearby solar-type stars, which have a mean metallicity of −0.14 with a standard deviation of 0.25. Six stars in that sample have BD companions, which have a mean metallicity of [Fe/H] = −0.05. The mean metallicity of our BD sample is slightly higher than the mean metallically of volume-limited nearby FGK dwarf stars. For example, Favata, Micela & Sciortino (1997) have analysed a volume-limited sample of 91 G and K dwarfs, yielding a mean metallicity of [Fe/H] = −0.08 with a standard deviation of 0.26. Nordström et al. (2004) have derived metallicity for 166 82 nearby F and G dwarf stars with a mean of −0.14 and a dispersion of 0.19 dex. Sousa et al. (2011) found that a mean metallicity for the CORALIE survey sample of 1248 stars and the high accuracy radial velocity planet searcher (HARPS) survey sample of 582 stars is [Fe/H] = −0.11 and −0.10, respectively. However, since some exoplanet surveys choose samples biased towards metal-rich stars (e.g. Valenti & Fischer 2005), the slightly higher mean metallicity of BD host stars is possibly caused by the sample bias.
After comparing the BD host star metallicities with the volume-limited sample from Sousa et al. (2011) and the planet search sample from Valenti & Fischer (2005), we find that the BD host star metallicity distribution is consistent with the combination of these two samples. This means that we cannot interpret the BD host star sample as metal rich. We compared metallicities of BD host stars with that of giant planet (|$1<m\sin i<5\,M_{\text{Jup}}$|) host stars. The data of giant planet host stars are taken from the Exoplanet Orbit Database (Wright et al. 2011). A K-S test shows that the probability of these two samples being selected from the same distribution is 5 × 10−4, with a statistical distance D0 = 0.267. This result indicates that the two samples are significantly different from each other. Here, D0 quantifies the distance between the empirical distribution function of the two samples. The bigger D0 is, the smaller the chance that these two samples are drawn from the same distribution. Because the BD sample is rather small when comparing with the giant planet sample, we decided to do a Monte Carlo bootstrapping simulation to test whether the result shown above is due to small number statistics. In this simulation, we first combined the BD hosts and the giant planet hosts into one metallicity sample. A new BD host metallicity sample and a new giant planet host metallicity sample were drawn randomly from this combined sample. Then, we calculated the statistical distance, Di, between the new BD host metallicity sample and the new giant planet host metallicity sample. This process was repeated for 10 000 times. The probability that this new statistical distance Di from our simulation is greater than the original distance D0 is only 0.03 per cent (3 out of 10 000 simulation). This result supports the idea that BD host stars do have very different metallicity distribution from that of the giant planet host stars, and it is not due to small number statistics.
We investigated the correlation between BD host star metallicities and BD masses. The Spearman's rank correlation coefficient of the BD mass and their host star metallicity is 0.07 with a 61 per cent significance, suggesting there is no significant correlation between the BD mass and their host star metallicity.
We also divided the BD companions into two subsamples according to their masses. The cumulative metallicity distribution for host stars with BD companion (minimum) masses above and below 42.5MJup is shown in Fig. 6. The main difference between these two distributions is at the lower metallicity end. Currently, no BDs with (minimum) masses greater than 42.5MJup have been found around stars with [Fe/H] < −0.5, while several BDs with (minimum) masses lower than 42.5MJup have been found in this metallicity regime. A K-S test has been conducted to show that the probability of these two sample metallicities being drawn from the same distribution is 70 per cent, which suggests there is no significant difference between these two samples regarding their metallicity distributions.
Cumulative metallicity distribution of host stars with BD companion masses above (dashed line) and below (solid line) 42.5MJup. Also shown for comparison are cumulative metallicity distributions of the planet search sample from Valenti & Fischer (2005), the CORALIE planet search sample (Sousa et al. 2011) and giant planet sample from the Exoplanet Orbit Database (Wright et al. 2011).
4 DISCUSSION
4.1 Two different brown dwarf populations
Our study suggests that BDs with masses lower than ∼43MJup have an eccentricity distribution consistent with that of giant planets in the mass–eccentricity diagram, while BDs with masses above ∼43MJup have the star-like eccentricity distribution (Fig. 5). Our mass limit is consistent with the minimum of the mass functions of planet and stellar companions in the BD mass region, |$43^{+14}_{-23}M_{\rm Jup}$|, derived by Grether & Lineweaver (2006) using their stellar companion and giant planet sample within 50 pc around the sun. This mass function minimum is also consistent with that derived by Sahlmann et al. (2011a), who found a void in the mass range between 25 and 45MJup using the data from the CORALIE RV survey. They further suggested that there may be a possible dividing line between massive planets and substellar companions. Schneider et al. (2011) have chosen arbitrarily and probably provisionally 25MJup as the upper limit of massive planets based on previous studies (e.g. Baraffe, Chabrier & Barman 2010; Sahlmann et al. 2011a).
Our BD sample is, therefore, naturally divided into two different groups with the mass limit of ∼42.5MJup. The eccentricity distribution of low-mass BDs appears to be consistent with the prediction from the ‘planet–planet scattering’ model (Rasio & Ford 1996; Chatterjee et al. 2008; Ford & Rasio 2008), while the eccentricity distribution of massive BDs appears to be similar to that of stellar binaries (Halbwachs et al. 2003) as shown in Section 3.3. The eccentricity distributions of these two groups support that BDs may form differently: BDs below this mass limit form in protoplanetary discs around host stars and above this mass limit form like stellar binary systems. This is supported by our analysis results. The existence of a large population of long-period low-eccentricity BDs (P > 300 d and e < 0.4) serves as evidence to support the BD formation scenario in the protoplanetary discs for those companions with masses below 42.5MJup, while the lack of long-period and low-eccentric BD companions with masses above 42.5MJup appears to support the BD formation scenario like stellar binary formation. Nevertheless, a small number of BDs in each of these two mass regions may form in an opposite formation mechanism, but our sample is not sufficient to distinguish these minor groups.
Next, we will address the question of why the two BD populations tend to have different mass ranges. Jumper & Fisher (2013) have demonstrated analytically that fragmentation within isolated turbulent giant molecular cloud naturally explains the dearth of low-mass BDs around solar-type stars. They find that the probability of a BD companion orbiting closely to a solar-type star decreases sharply with its mass. BDs formed this way may then experience an inward disc migration and destruction stage through the interaction with the protostar disc (Armitage & Bonnell 2002). This mechanism is more sensitive to low-mass BDs than to high-mass BDs, thus could reduce the number of low-mass BD companions formed this way significantly. So, BD companions formed the same way as stars tend to have masses higher than several tens of Jupiter mass since the low-mass BD companions are either formed further away from their host stars (Jumper & Fisher 2013) or are depleted later as a consequence of inward migration (Armitage & Bonnell 2002). While for BD companions formed in the protoplanetary disc through disc-instability mechanism, their masses are limited by the total disc mass and their ability of accreting material from the disc. Rice et al. (2003) show that the number of substellar objects formed immediately following disc fragmentation drops rapidly beyond several Jupiter mass and with a maximum mass of 15.6MJup given a disc mass of |$0.2\,\text{M}_{\odot }$|. The maximum mass of BDs formed this way depends on disc properties (disc mass, surface density profile, etc.) and their subsequent evolution, which is likely to be around several tens of Jupiter mass. So, in theory, BD companions around solar-type stars formed in protoplanetary discs through disc-instability mechanism tend to have smaller masses than those of BD companions formed the same way as stars. This explains qualitatively why the two BD populations have different mass ranges. However, to explain exactly why the two populations are divided around 42.5MJup, comprehensive high-resolution simulations able to model full star formation process by including all the relevant ingredients (gravity, hydrodynamics, chemistry, radiative transfer and magnetic fields) are needed, which still have formidable numerical challenges to overcome (Bate 2012).
4.2 Implications of metallicity distribution on BD formation mechanisms
Our study of metallicity distribution of BDs host stars seems to support the disc-instability mechanism (Boss 1997, 2002, 2006) for those BDs formed in the planetary discs, while it is inconsistent with the prediction of core-accretion formation mechanism (Pollack et al. 1996; Ida & Lin 2004; Alibert et al. 2005). Currently, there are two hotly contested theories about giant planet formations: core-accretion and disc gravitational instability. In the core-accretion scenario, giant planets form more efficiently around metal-rich planetary discs than metal-poor planetary discs because the higher the grain content of the disc is, the easier the metal core is to build for giant planets (Pollack et al. 1996; Ida & Lin 2004; Alibert et al. 2005). In contrast, the disc gravitational instability process allows similar formation efficiency for both metal-rich and metal-poor giant planets. Previous results show that strong correlation between metallicity and giant planet occurrence rate around solar-type stars (Santos, Israelian & Mayor 2001; Valenti & Fischer 2005; Johnson et al. 2010) strongly supports the core-accretion formation scenario for giant planet formation (Pollack et al. 1996; Ida & Lin 2004; Alibert et al. 2005). However, our result, showing no correlation between the BD occurrence rate and metallicity, appears to support the disc-instability mechanism for formation of most of the low-mass BDs in planetary discs (Rice et al. 2003).
For stellar companions, there appears to be a weak anticorrelation between metallicity and stellar companion occurrence rate (Raghavan et al. 2010), i.e. lower metallicity clouds might be more likely to fragment to form binary stars. If this applies to massive BDs, then we expect this anticorrelation. However, our current sample is too small to tell, but is at least not inconsistent with this statistics.
4.3 Minimum mass used
In this study, most of the BD (candidates) do not have a true mass measured. Instead, we use their minimum mass, m sin i, to do the statistical study. In the future, missions like GAIA could do astrometry measurements of these stars and give true masses of these BD candidates. This could help us to understand better about the BD population and their formation mechanisms.
To investigate how the use of minimum mass of BDs will impact our two BD population hypothesis, we also carried out a Monte Carlo simulation. The inclination angles i of BDs without true masses measured are assumed to distribute isotropically [uniformly in cos (i)]. We then use the minimum mass [m sin (i)] and inclination angle i to calculate the simulated ‘true’ mass for BDs without the true mass measured. This simulation is repeated for 10 000 times. The first thing to test is the gap identified in the period–mass diagram as shown in Fig. 2. The number density ratio between this gap's adjacent region and this gap is bigger than 3 in 78 per cent of our Monte Carlo simulations, bigger than 2 in 94 per cent of our simulations and bigger than 1 in all of our simulations. Our results indicate that the gap region always has a smaller number density than its adjacent region after we account for the inclination angle information.
In this same simulation, we also tested if the two BD populations have different eccentricity distribution. We use a two-dimensional K-S test to calculate the probability, ps, that the two populations are drawn from the same distribution for 10 000 times. The median value of the probability ps is 4.6 per cent. So, for most of the times, the two populations have different eccentricity distribution even if we take into account of the inclination angle. It is also worth pointing out that, although not happening very often (∼500 out of 10 000 times), the two populations sometimes do appear to have a similar (ps > 20 per cent) eccentricity distribution. So, in the future, a larger sample of BDs with true masses measured via transit, astrometry or microlensing observation would be necessary to test this two population hypothesis.
5 SUMMARY
We have searched the literature and presented a catalogue of BD companions around solar-type stars found by RV, transiting and astrometry observations. We have studied distribution of different parameters of BD companions around solar-type star and found that
the number of BD companions is increasing with their period, similar to the distributions of giant planets and low-mass binaries;
BD companions are almost depleted at P < 100 d and 30 < M < 55MJup in the period–mass diagram;
BD companions with (minimum) masses below 42.5MJup have eccentricity distribution consistent with that of massive planets;
BD companions with (minimum) masses above 42.5MJup have eccentricity distribution consistent with that of binaries, which shows the expected circularization for periods below 12 d, caused by tidal forces over the age of the Galaxy, followed by a roughly flat distribution;
host stars of BD companions are not metal rich and have significantly different metallicity distribution when comparing with host stars of giant planets, suggesting a formation scenario at least partly different from the core-accretion scenario.
The distribution of BD and their host star properties presented in this paper may lend support to such a picture: (1) BD companions with (minimum) masses below 42.5MJup form primarily in a protoplanetary disc through the disc gravitational instability scenario, and their eccentricity is excited through scattering with other objects formed in this disc or interactions with disc/third body; (2) BD companions with (minimum) masses above 42.5MJup dominantly form like stars, through molecular cloud fragmentation, similar to the formation of a stellar binary system.
We want to thank an anonymous referee for his/her comments, which helped to improve the quality of this paper. This research has made use of the Exoplanet Orbit Database and the Exoplanet Data Explorer at exoplanets.org. We thank Neil Thomas for proof reading our paper. We acknowledge the support from DoD Coopeative Agreement W911NF-09-2-0017, Dharma Endowment Foundation and the University of Florida.
