Astronomy and Astrophysics – Astronomy
Scientific paper
Dec 1999
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1999aas...19511105h&link_type=abstract
American Astronomical Society, 195th AAS Meeting, #111.05; Bulletin of the American Astronomical Society, Vol. 31, p.1539
Astronomy and Astrophysics
Astronomy
Scientific paper
Recent HST STIS observations have revealed the spectrum of the central star in Eta Carinae for the first time. These observations clearly show that the optical spectrum of the central star is dominated by emission lines of H, He 1, and Fe 2. Its spectrum is qualitatively similar to the extreme P Cygni star HDE 316285. Using the non-LTE atmosphere code of Hillier and Miller (1998) we have performed a spectroscopic investigation of the central star. Previously measured IR fluxes indicate that the luminosity of the system is approximately 5x 106 Lsun (for a distance of d=2.5 kpc), which we adopt as the luminosity of the central star. An excellent fit is obtained to the emission line spectrum using a mass loss rate of 10-3Msun yr-1, a terminal wind velocity of 500 kms-1, and a solar Fe abundance (by mass). Due to degeneracies in the model it is difficult to constrain both the effective temperature and the H/He abundance ratio. The most significant discrepancy is that the strength of the P Cygni absorption components is overestimated, particularly on the Fe 2\ emission lines. These discrepancies may be due to asymmetries in the stellar wind and/or time variability. There may also be a problem for our models in matching the UV spectrum shortward of 1600 Angstroms, but STIS observations of the central star are not yet available, while earlier GHRS observations may be contaminated by nebula emission and/or a companion star. We discuss the implications of our results for the current evolutionary status of η Car, and for the binary model of Damineli et al. (1997). This research was supported in part by NASA through a grant from the STScI, which is operated by AURA, under NASA contract NAS5-26555. Additional support was provided by NASA grant NAG5-8211.
Davidson Kris
Gull Ted
Hillier Desmond John
Kazunori Ishibashi K.
No associations
LandOfFree
Eta Carinae: The Central 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 Eta Carinae: The Central Star, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Eta Carinae: The Central Star will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1747894