The ultraviolet spectrum of the O-type subdwarf HD 49798.
Abstract
The O-type subdwarf (O6p) single-lined spectroscopic binary HD 49798, with an orbital period of 1.5477 d, has been observed by the International Ultraviolet Explorer satellite, to aid in analyses of O type photospheres. Four high resolution (0.1A) spectra are found in the far-ultraviolet region, and two high resolution (0.2A) spectra are found in the mid-ultraviolet region. Numerous absorption lines are identified in the spectra of the star, most of which are attributable to Fe V lines at wavelengths of 1270 to 1500 A. Fe IV lines are also identified at wavelengths of 1500 to 1860 A. The strong Fe V features are found to have no corresponding analogs in the Kurucz and Peytremann (1975) list, and the total line blanketing for stars of spectral type O6 to B0 is discovered to be underestimated by at least a factor of four. In addition, mass loss from the subdwarf observed in the N V resonance doublet at wavelengths of 1238 A and 1242 A is discussed, indicating the existence of a hot stellar wind.
- Publication:
-
The Astrophysical Journal Supplement Series
- Pub Date:
- July 1981
- DOI:
- 10.1086/190746
- Bibcode:
- 1981ApJS...46..255B
- Keywords:
-
- Binary Stars;
- Early Stars;
- O Stars;
- Stellar Spectra;
- Subdwarf Stars;
- Ultraviolet Spectra;
- Absorption Spectra;
- Abundance;
- Atmospheric Models;
- Iue;
- Line Spectra;
- Spectrum Analysis;
- Tables (Data);
- Astronomy