2002A&A...384..545R


C.D.S. - SIMBAD4 rel 1.7 - 2020.02.23CET08:56:46

2002A&A...384..545R - Astronomy and Astrophysics, volume 384, 545-553 (2002/3-3)

Abundance stratification and pulsation in the atmosphere of the roAp star γ Equulei.

RYABCHIKOVA T., PISKUNOV N., KOCHUKHOV O., TSYMBAL V., MITTERMAYER P. and WEISS W.W.

Abstract (from CDS):

We present the evidence for abundance stratification in the atmosphere of the rapidly oscillating Ap star γ Equ. Ca, Cr, Fe, Ba, Si, Na seem to be overabundant in deeper atmospheric layers, but normal to underabundant in the upper layers with a transition in the typical line forming region of -1.5<logτ5000←0.5. This stratification profile agrees well with diffusion theory for Ca and Cr, developed for cool magnetic stars with a weak mass loss of ≃2.5x10–15M/yr. Pr and Nd from the rare earth elements have an opposite profile. Their abundance is more than 6dex higher above logτ5000≃-8.0 than in the deeper atmospheric layers. We further discuss the implications of abundance stratification in the context of radial velocity amplitudes and phases observed by Kochukhov & Ryabchikova (2001A&A...374..615K) for a variety of spectral lines and elements using high spectral and time resolved, high S/N observations.

Abstract Copyright:

Journal keyword(s): stars: chemically peculiar - stars: abundances - stars: oscillations - stars: individual: γ Equ

Simbad objects: 7

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Number of rows : 7

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
#notes
1 HD 32115 SB* 05 00 39.8076842834 -02 03 57.710120718   6.60 6.32     A9V 62 0
2 * 53 Cam a2* 08 01 42.4313674994 +60 19 27.801603076   6.177 6.008     A3VpSrSiCrEu 378 0
3 HD 83368 a2* 09 36 25.40686 -48 45 04.2549   6.480 6.232     A8VSrCrEu+F9V 256 0
4 V* PP Vir a2* 14 04 48.9378026422 +05 24 51.462293664   8.70 8.29     F0 68 0
5 * alf Cir a2* 14 42 30.4195804 -64 58 30.493451 3.55 3.43 3.19 2.96 2.86 A7VpSrCrEu 328 0
6 * bet CrB a2* 15 27 49.7315305 +29 06 20.522375 4.08 3.97 3.68 3.50 3.45 F2VpSrCrEuSi 651 0
7 * gam Equ a2* 21 10 20.5001160337 +10 07 53.682085548 5.03 4.94 4.68 4.43 4.32 A9VpSrCrEu 511 1

    Equat.    Gal    SGal    Ecl

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2020.02.23-08:56:46

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