Astronomy and Astrophysics – Astrophysics
Scientific paper
May 1994
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1994a%26a...285..573n&link_type=abstract
Astronomy and Astrophysics 285, 573-584 (1994)
Astronomy and Astrophysics
Astrophysics
105
The Galaxy: Center, Infrared: Stars, Stars: Early-Type, Stars: Emission-Line, Stars: Supergiants
Scientific paper
We present near-infrared spectroscopy and unified atmosphere/wind models of the brightest HeI 2.058μm emission line star (hereafter denoted AF) in the Galactic center. The near-infrared spectrum of this star exhibits broad emission lines of HeI and H, with the strongest line at 2.058μm showing shallow P-Cygni absorption, strengthening the stellar wind interpretation for the origin of the lines. None of the higher excitation lines typical of classical Wolf-Rayet stars are detected. From the atmosphere models we conclude that the star is undergoing extensive mass loss (dM/dt~6 to 10 x 10^-5^ Msun/yr), has a luminosity of 2 to 3 10^5^Lsun_, a moderate end velocity (Vinfinity_ ~ 700 km/s) and a strongly enhanced helium abundance (N_He_/N_H_>.5). The AF star has an effective temperature of about 20,000K and produces <=10^48^ Lyman continuum photons per second and < 10^38^ helium continuum photons. These parameters are similar to those of evolved blue supergiants of type Ofpe/WN9 found in the Magellanic Clouds. Extrapolating from the AF star it is likely that the emission line stars so far detected (~ 15) contribute a large fraction of the total luminosity (~10^7^Lsun_), and a significant fraction of the Lyman continuum luminosity (~10^6^Lsun_) of the central parsec. However, the Hei stars make no contribution to the He ionizing photons. Less evolved, hotter O and/or Wolf-Rayet stars may provide the Hei ionizing flux, and also contribute to the Lyman flux.
Drapatz Siegfried
Geballe Thomas Ronald
Genzel Reinhard
Hillier Desmond John
Krabbe Alfred
No associations
LandOfFree
The nature of the brightest galactic center HeI emission line star does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with The nature of the brightest galactic center HeI emission line star, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The nature of the brightest galactic center HeI emission line star will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-879968