2021A&A...650A.125D


Query : 2021A&A...650A.125D

2021A&A...650A.125D - Astronomy and Astrophysics, volume 650A, 125-125 (2021/6-1)

Fundamental properties of a selected sample of Ap stars: Inferences from interferometric and asteroseismic constraints.

DEAL M., CUNHA M.S., KESZTHELYI Z., PERRAUT K. and HOLDSWORTH D.L.

Abstract (from CDS):


Context. Magnetic fields influence the formation and evolution of stars and impact the observed stellar properties. magnetic A-type stars (Ap stars) are a prime example of this. Access to precise and accurate determinations of their stellar fundamental properties, such as masses and ages, is crucial to understand the origin and evolution of fossil magnetic fields.
Aims. We propose using the radii and luminosities determined from interferometric measurements, in addition to seismic constraints when available, to infer fundamental properties of 14 Ap stars previously characterised.
Methods. We used a grid-based modelling approach, employing stellar models computed with theCESTAM stellar evolution code, and the parameter search performed with theAIMS optimisation method. The stellar model grid was built using a wide range of initial helium abundances and metallicities in order to avoid any bias originating from the initial chemical composition. The large frequency separations (Δν) of HR 1217 (HD 24712) and α Cir (HD 128898), two rapidly oscillating Ap stars of the sample, were used as seismic constraints.
Results. We inferred the fundamental properties of the 14 stars in the sample. The overall results are consistent within 1σ with previous studies, however, the stellar masses inferred in this study are higher. This trend likely originates from the broader range of chemical compositions considered in this work. We show that the use of Δν in the modelling significantly improves our inferences, allowing us to set reasonable constraints on the initial metallicity which is, otherwise, unconstrained. This gives an indication of the efficiency of atomic diffusion in the atmospheres of roAp stars and opens the possibility of characterising the transport of chemical elements in their interiors.

Abstract Copyright: © ESO 2021

Journal keyword(s): stars: chemically peculiar - stars: evolution - stars: oscillations - stars: variables: general - stars: magnetic field

Simbad objects: 17

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Number of rows : 17
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2024
#notes
1 HD 1217 * 00 16 24.2736732840 -35 18 45.130241952   10.72 9.55     G8IV 7 0
2 V* GO And a2* 00 50 18.2653153128 +45 00 08.135537076 6.13 6.16 6.15     A3VpSiSrCrEuKsn 123 0
3 HD 12019 * 01 58 21.4293352680 +18 16 27.746066280   8.60 8.41 8.4   A3 12 0
4 V* DO Eri a2* 03 55 16.1313315312 -12 05 56.727712752 6.35 6.32 6.00     A9VpSrEuCr 396 0
5 * alf CMa SB* 06 45 08.91728 -16 42 58.0171 -1.51 -1.46 -1.46 -1.46 -1.43 A0mA1Va 1523 0
6 * 17 Com a2* 12 28 54.7022406648 +25 54 46.265813136   5.208 5.236     B9VCrEu 279 0
7 * 21 Com a2* 12 31 00.5605002264 +24 34 01.797245328   5.496 5.436     A2pv 281 0
8 * o Vir a2* 13 34 07.9312445507 +03 39 32.288960317 4.96 4.96 4.94 4.86 4.89 ApEuCrSr 343 0
9 * 84 UMa a2* 13 46 35.6567876472 +54 25 57.643558644   5.632 5.675     A0VpSrCrEu 158 0
10 * alf Cir a2* 14 42 30.4195804 -64 58 30.493451 3.55 3.43 3.19 2.96 2.86 A7VpSrCrEu 363 0
11 * bet CrB a2* 15 27 49.7315305 +29 06 20.522375 4.08 3.97 3.68 3.50 3.45 F2VpSrCrEuSi 684 0
12 V* V451 Her a2* 17 01 33.0515292528 +14 56 58.988031648 6.39 6.35 6.31     A0VpSiSrCrEu 177 0
13 * 10 Aql a2* 18 58 46.9240671288 +13 54 23.941711692 6.23 6.14 5.89     A7VpSrEu_Ksn 284 0
14 V* V1291 Aql a2* 19 53 18.7357174440 -03 06 52.063556976   5.837 5.619     F0VpSrCrEu 276 0
15 * gam Equ a2* 21 10 20.5000721160 +10 07 53.691967776 5.03 4.94 4.68 4.43 4.32 A9VpSrCrEu 549 0
16 HD 204411 a2* 21 26 51.6219389280 +48 50 06.599806584 5.54 5.38 5.31     A4VpSiCrHg 184 0
17 * kap Psc a2* 23 26 55.9558721856 +01 15 20.177913204 4.94 4.98 4.94 4.87 4.90 A2VpSrCrSi 276 0

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