Reference : Spectroscopic monitoring of the Herbig Ae star HD 104237 - II. Non-radial pulsations,...
Scientific journals : Article
Physical, chemical, mathematical & earth Sciences : Physics
http://hdl.handle.net/2268/115155
Spectroscopic monitoring of the Herbig Ae star HD 104237 - II. Non-radial pulsations, mode analysis and fundamental stellar parameters
English
Fumel, Aurélie [Université de Liège - ULg > Département d'astrophys., géophysique et océanographie (AGO) > Astrophysique et traitement de l'image >]
Böhm, Torsten [Université de Toulouse; UPS-OMP; IRAP;, Toulouse, France ; CNRS; IRAP, 14 avenue Edouard Belin, 31400, Toulouse, France > > > >]
2012
Astronomy and Astrophysics
EDP Sciences
Yes (verified by ORBi)
International
0004-6361
1432-0746
Les Ulis
France
[en] stars: pre-main sequence ; stars: oscillations ; stars: individual: HD 104237 ; stars: binaries: spectroscopic ; stars: fundamental parameters
[en] Context. Herbig Ae/Be stars are intermediate-mass pre-main sequence (PMS) stars showing signs of intense activity and strong stellar winds, whose origin is not yet understood in the frame of current theoretical models of stellar evolution for young stars. In addition, the evolutionary tracks of the earlier Herbig Ae stars cross the theoretical PMS instability strip located roughly in the same area of the HR diagram as the δ Scuti variables. Many of these stars exhibit pulsations of δ Scuti type. Aims. Understanding the internal structure of pulsating Herbig Ae stars based on asteroseismic studies will help constraining the
origin of their tremendous activity, winds, and variability. It is therefore necessary to investigate the location of the PMS instability strip and of its boundaries, and to extend the sample of observed and studied pulsating Herbig Ae stars. The aim of this work was to carry out a thorough analysis of the line profile variations of the prototype Herbig Ae star HD104237 based on high-resolution spectroscopy and to redetermine precisely its fundamental parameters, which are the basic ingredients of a forthcoming asteroseismic
modeling. Methods. HD104237 is a pulsating Herbig Ae star with eight detected frequencies based on the analysis of radial velocity variations. In this article, we reinvestigated an extensive high-resolution quasi-continuous spectroscopic data set in order to search for very faint indications of non-radial pulsations in the line profile by working on dynamical spectra of equivalent photospheric (LSD) profiles of HD104237. A 2D Fourier analysis (F2D) was performed of the entire profile and the temporal variation of the central depth of the line was studied with the time-series analysis tools Period04 and SigSpec. We present the results of these analysis including the mode identification corresponding to the detected dominant frequency, as well as a new determination of its fundamental stellar parameters. Results. The analysis of spectroscopic data set of April 22 - 25 obtained at SAAO in 1999 has confirmed the presence of multiple oscillation modes of low-degree ℓ in HD104237 and led to the first direct detection of a non-radial pulsation mode in this star: the dominant mode F1 was identified by the Fourier 2D method having a degree ℓ value comprised between 1 and 2, the symmetry of the pattern variation indicating an azimuthal order of ± 1. The detailed study of the fundamental stellar parameters has provided a Teff, log g, and iron abundance of 8550 ± 150 K, 3.9 ± 0.3, and −4.38 ± 0.19 (i.e. [Fe/H]= +0.16 ± 0.19 ), respectively.
Researchers ; Professionals
http://hdl.handle.net/2268/115155
10 pages, 8 figures, 5 tables

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