2004A&A...425..179V

Query : 2004A&A...425..179V

2004A&A...425..179V - Astronomy and Astrophysics, volume 425179-185 (2004/10-1)

Asteroseismic signatures of helium gradients in main-sequence A stars: application to the roAp star HD 60435.

VAUCLAIR S. and THEADO S.

Abstract (from CDS):

Asteroseismology is found to be a excellent tool for detecting diffusion-induced helium gradients inside main-sequence A stars. Models have been computed for 1.6 and 2.0M☉ stars with pure helium diffusion, at different ages, so that the helium gradient lies at different depths inside the star. The adiabatic oscillation frequencies have been analysed and compared with those of a model without diffusion. Clear signatures of the diffusion-induced helium gradient are found in the so-called ``second differences'': these frequency differences present modulations due to the partial reflexion of the sound waves on the layer where the helium gradient occurs. A tentative application to the roAp star HD 60435, which presents enough detected oscillation frequencies for the test to be possible, is very encouraging. The results suggest the presence of a helium gradient inside the star, which is consistent with the idea that the triggering of the oscillations is due to the hydrogen κ-mechanism.

Abstract Copyright: ∼

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

Simbad objects: 1

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Number of rows : 1
N Identifier Otype ICRS (J2000)
RA 		ICRS (J2000)
DEC 		Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2026 		#notes
1 V* V409 Car a2* 07 30 56.9886639144 -57 59 28.238685684   9.13 8.89     ApSr(Eu) 132 0

Query : 2004A&A...425..179V

Basic data :
V* V409 Car -- alpha2 CVn Variable
Other object types: otypes_help 		a2* (), * (HD,CD,...), Ro* (2019MNRAS), V* (V*), UV (TD1), NIR (2MASS)
ICRS coord. (ep=J2000) : 		07 30 56.9886639144 -57 59 28.238685684 (Optical) [ 0.0129 0.0140 90 ] A 2020yCat.1350....0G
FK4 coord. (ep=B1950 eq=1950) : 		07 30 01.8117470097 -57 53 03.931868199 [ 0.0129 0.0140 90 ]
Gal coord. (ep=J2000) : 		269.6709565816408 -17.8022168402938 [ 0.0129 0.0140 90 ]
Proper motions mas/yr : 		-11.808 24.918 [0.017 0.018 90] A 2020yCat.1350....0G
Radial velocity / Redshift / cz : 		V(km/s) 18.80 [0.4] / z(~) 0.000063 [0.000001] / cz 18.80 [0.40]
   A 2006AstL...32..759G
Parallaxes (mas): 		4.0770 [0.0136] A 2020yCat.1350....0G
Spectral type: 		ApSr(Eu) D 1975MSS...C01....0H
Fluxes (6) :
B 9.13 [0.02] D 2000A&A...355L..27H
V 8.89 [0.01] D 2000A&A...355L..27H
G 8.868371 [0.002773] C 2022yCat.1355....0G
J 8.434 [0.024] C 2003yCat.2246....0C
H 8.393 [0.029] C 2003yCat.2246....0C
K 8.370 [0.027] C 2003yCat.2246....0C
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Identifiers (20) :
An access of full data is available using the icon Vizier near the identifier of the catalogue

HD 60435 GSC 08559-00038 Renson 16520 uvby98 100060435
CD-57 1762 HIC 36537 SAO 235263 V* V409 Car
CPC 20 1928 HIP 36537 TD1 10454 Gaia DR2 5486011553099475200
CPD-57 1246 2MASS J07305699-5759280 TIC 340006157 Gaia DR3 5486011553099475200
GEN# +1.00060435 PPM 336118 TYC 8559-38-1 Gaia DR1 5486011548802135936

References (132 between 1850 and 2026) (Total 132)
Simbad bibliographic survey began in 1850 for stars (at least bright stars) and in 1983 for all other objects (outside the solar system).
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Collections of Measurements Description of Measurements

Velocities : 1    Diameter : 1    Distance : 3    Var : 1    Plx : 6    PM : 4    SpT : 2   

   

External archives :

Archive data at HEASARC - High-Energy Astrophysics Science Archive Research Center

Link by name to the catalogue in VizieR :

HD 60435 CD-57 1762 CPD-57 1246 GSC 08559-00038 HIC 36537
HIP 36537 2MASS J07305699-5759280 PPM 336118 SAO 235263 TD1 10454
TYC 8559-38-1 uvby98 100060435 V* V409 Car Gaia DR2 5486011553099475200 Gaia DR3 5486011553099475200
Gaia DR1 5486011548802135936

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