An Analysis of the Pulsating Star SDSS J160043.6+074802.9 Using New Non-LTE Model Atmospheres and Spectra for Hot O Subdwarfs

Details An Analysis of the Pulsating Star SDSS J160043.6+074802.9 Using New Non-LTE Model Atmospheres and Spectra for Hot O Subdwarfs An Analysis of the Pulsating Star SDSS J160043.6+074802.9 Using New Non-LTE Model Atmospheres and Spectra for Hot O Subdwarfs

Jun 2011

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2011apj...733..100l&link_type=abstract

The Astrophysical Journal, Volume 733, Issue 2, article id. 100 (2011).

Astronomy and Astrophysics

Astronomy

2

Stars: Atmospheres, Stars: Fundamental Parameters, Stars: Individual: Sdss J160043.6+074802.9, Subdwarfs

Scientific paper

We first present our new grids of model atmospheres and spectra for hot subdwarf O (sdO) stars: standard non-LTE (NLTE) H+He models with no metals, NLTE line-blanketed models with C+N+O, and NLTE line-blanketed models with C+N+O+Fe. Using hydrogen and helium lines in the optical range, we make detailed comparisons between theoretical spectra of different grids in order to characterize the line-blanketing effects of metals. We find these effects to be dependent on both the effective temperature and the surface gravity. Moreover, we find that the helium abundance also influences in an important way the effects of line blanketing on the resulting spectra. We further find that the addition of Fe (solar abundance) leads only to incremental effects on the atmospheric structure as compared with the case where the metallicity is defined by C+N+O (solar abundances). We use our grids to perform fits on a 9 Å resolution, high signal-to-noise ratio (~300 blueward of 5000 Å) optical spectrum of SDSS J160043.6+074802.9, the only known pulsating sdO star. Our best and most reliable result is based on the fit achieved with NLTE synthetic spectra that include C, N, O, and Fe in solar abundances, leading to the following parameters : T eff = 68,500 ± 1770 K, log g = 6.09 ± 0.07, and log N(He)/N(H) = -0.64 ± 0.05 (formal fitting errors only). This combination of parameters, particularly the comparatively high helium abundance, implies that line-blanketing effects due to metals are not very large in the atmosphere of this sdO star.

Affiliated with

Also associated with

No associations

Rating

An Analysis of the Pulsating Star SDSS J160043.6+074802.9 Using New Non-LTE Model Atmospheres and Spectra for Hot O Subdwarfs 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 An Analysis of the Pulsating Star SDSS J160043.6+074802.9 Using New Non-LTE Model Atmospheres and Spectra for Hot O Subdwarfs, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and An Analysis of the Pulsating Star SDSS J160043.6+074802.9 Using New Non-LTE Model Atmospheres and Spectra for Hot O Subdwarfs will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-981198