The FU Orionis Binary System RNO 1B/1C
Abstract
Observations of CS (7→6) emission reveal a ≥3 Msun core, 1.8 × 104 AU in size, surrounding the FU Orionis binary system RNO 1B/1C. Fractional chemical abundances, calculated from LVG and LTE codes, are mostly similar to those in the cold core TMC 1. However, values for SiO/H2 and CR3OH/H2 are enhanced, possibly by sputtering reactions or grain-grain collisions in the outflow associated with the young stars. Aperture synthesis maps of the 2.6 and 3.1 mm continuum emission at ∼5" and ∼9" resolution, respectively, reveal that RNO 1C is surrounded by a flattened, dusty envelope, ∼5000 AU in size, with mass ≥1.1 Msun. High spatial resolution (∼3") interferometer observations of CS (2→1) emission may trace the dense walls of ah outflow cavity comprised of two concentric arcs with dynamical ages of 4 × 103 and 1 × 104 yr. The velocity structure of lower density gas imaged in the CO (1→0) transition is consistent with the arcs being formed by two energetic FU Orionis outbursts. Each event may have imparted more than 4 Msun km s-1 to the outflow, implying outburst mass loss rates of ∼10-4 Msun yr-1. It appears that RNO 1C is probably the driving source for the outflow and that, while pre-main sequence stars are in the FU Orionis stage, outbursts may dominate both outflow morphology and energetics.
- Publication:
-
The Astronomical Journal
- Pub Date:
- July 1995
- DOI:
- 10.1086/117526
- Bibcode:
- 1995AJ....110..354M
- Keywords:
-
- STARS: PRE-MAIN SEQUENCE;
- STARS: MASS-LOSS;
- BINARIES: CLOSE