2009A&A...493..159T


C.D.S. - SIMBAD4 rel 1.7 - 2020.04.10CEST21:44:33

2009A&A...493..159T - Astronomy and Astrophysics, volume 493, 159-174 (2009/1-1)

New light on the driving mechanism in roAp stars. I. Effects of metallicity.

THEADO S., DUPRET M.-A., NOELS A. and FERGUSON J.W.

Abstract (from CDS):

Observations suggest that a relationship exists between the driving mechanism of roAp star pulsations and the heavy element distribution in these stars. We attempt to study the effects of local and global metallicity variations on the excitation mechanism of high order p-modes in A star models. We developed stellar evolutionary models to describe magnetic A stars with different global metallicity or local metal accumulation profiles. These models were computed with CLES (``Code Liegeois d'evolution stellaire''), and the stability of our models was assessed with the non-adiabatic oscillation code MAD. Our models reproduce the blue edge of the roAp star instability strip, but generate a red edge hotter than the observed one, regardless of metallicity. Surprisingly, we find that an increase in opacity inside the driving region can produce a lower amount of driving, which we refer to as the ``inverse κ-mechanism''.

Abstract Copyright:

Journal keyword(s): diffusion - stars: abundances - stars: chemically peculiar - stars: evolution - stars: interiors - Sun: oscillations

Status at CDS:  

Simbad objects: 8

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Number of rows : 8

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 V* DO Eri a2* 03 55 16.1314636284 -12 05 56.729555672 6.35 6.32 6.00     A9VpSrEuCr 374 0
2 V* V816 Cen dS* 11 37 37.0411005456 -46 42 34.875395453 8.99 8.79 8.03     F8/G0p 286 0
3 HD 116114 PM* 13 21 46.3077068552 -18 44 31.541856988   7.34 7.02     F0VpSrCrEu 118 0
4 * bet CrB a2* 15 27 49.7315305 +29 06 20.522375 4.08 3.97 3.68 3.50 3.45 F2VpSrCrEuSi 652 0
5 * gam Equ a2* 21 10 20.5001160337 +10 07 53.682085548 5.03 4.94 4.68 4.43 4.32 A9VpSrCrEu 512 1
6 HD 204411 a2* 21 26 51.6210422364 +48 50 06.598904376 5.54 5.38 5.31     A4VpSiCrHg 172 0
7 V* MM Aqr a2* 22 33 12.3249013034 -20 02 21.883718530   10.058 9.582     A(pEuSrCr) 34 0
8 V* BP Gru a2* 23 01 46.8212643426 -44 50 26.878058323   7.99 7.52     ApSrSi: 114 0

    Equat.    Gal    SGal    Ecl

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2020.04.10-21:44:33

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