Article (Scientific journals)
Spectral Analysis and Abundances of the Post-HB Star HD 76431
Khalack, V.; Yameogo, B.; LeBlanc, F. et al.
2014In Monthly Notices of the Royal Astronomical Society, 445, p. 4086
Peer Reviewed verified by ORBi
 

Files


Full Text
MNRAS-2014-Khalack-4086-93.pdf
Publisher postprint (585.96 kB)
Request a copy

All documents in ORBi are protected by a user license.

Send to



Details



Abstract :
[en] HD76431 is a slow rotating post-HB star that shows an underabundance of helium by 0.5 dex relative to the solar value. These observational facts suggest that atomic diffusion could be active in its atmosphere. We have used the MMT and Bok spectra to estimate the atmospheric parameters of the target star using the model atmospheres and synthetic spectra calculated with TLUSTY and SYNSPEC. The derived values of the effective temperature, surface gravity, helium abundance are consistent with those obtained by Ramspeck et al. (2001b). It appears that NLTE effect are not important for HD76431. We have used Stokes I spectra from ESPaDOnS at CFHT to perform an abundance analysis and a search for observational evidence of vertical stratification of the abundance of certain elements. The results of our abundance analysis are in good agreement with previously published data with respect to average abundances. Our numerical simulations show that carbon and nitrogen reveal signatures of vertical abundance stratification in the atmosphere of HD76431. It appears that the carbon abundance increases toward the deeper atmospheric layers. Nitrogen also shows a similar behaviour, but in deeper atmospheric layers we obtain a significant dispersion for the estimates of its abundance. To our knowledge, this is the first demonstration of vertical abundance stratification of metals in a post-HB star and up to now it is the hottest star to show such stratification features. We also report the detection of two SiIII and one TiIII emission lines in the spectra of HD76431 that were not detected in previous studies.
Disciplines :
Space science, astronomy & astrophysics
Author, co-author :
Khalack, V.
Yameogo, B.
LeBlanc, F.
Fontaine, G.
Green, E.M.
Van Grootel, Valérie  ;  Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Astrophysique stellaire théorique et astérosismologie
Petit, P.
Language :
English
Title :
Spectral Analysis and Abundances of the Post-HB Star HD 76431
Publication date :
December 2014
Journal title :
Monthly Notices of the Royal Astronomical Society
ISSN :
0035-8711
eISSN :
1365-2966
Publisher :
Blackwell Publishing, Oxford, United Kingdom
Volume :
445
Pages :
4086
Peer reviewed :
Peer Reviewed verified by ORBi
Available on ORBi :
since 29 September 2014

Statistics


Number of views
28 (1 by ULiège)
Number of downloads
1 (0 by ULiège)

Scopus citations®
 
5
Scopus citations®
without self-citations
3
OpenCitations
 
5

Bibliography


Similar publications



Contact ORBi