2013A&A...555A.100D


C.D.S. - SIMBAD4 rel 1.7 - 2019.10.13CEST23:37:59

2013A&A...555A.100D - Astronomy and Astrophysics, volume 555A, 100-100 (2013/7-1)

Spectrally resolved interferometric observations of α Cephei and physical modeling of fast rotating stars.

DELAA O., ZOREC J., DOMICIANO DE SOUZA A., MOURARD D., PERRAUT K., STEE P., FREMAT Y., MONNIER J., KRAUS S., CHE X., BERIO P., BONNEAU D., CLAUSSE J.M., CHALLOUF M., LIGI R., MEILLAND A., NARDETTO N., SPANG A., McALISTER H., TEN BRUMMELAAR T., STURMANN J., STURMANN L., TURNER N., FARRINGTON C. and GOLDFINGER P.J.

Abstract (from CDS):

When a given observational quantity depends on several stellar physical parameters, it is generally very difficult to obtain observational constraints for each of them individually. Therefore, we studied under which conditions constraints for some individual parameters can be achieved for fast rotators, knowing that their geometry is modified by the rapid rotation which causes a non-uniform surface brightness distribution. We aim to study the sensitivity of interferometric observables on the position angle of the rotation axis (PA) of a rapidly rotating star, and whether other physical parameters can influence the determination of PA, and also the influence of the surface differential rotation on the determination of the β exponent in the gravity darkening law that enters the interpretation of interferometric observations, using α Cep as a test star. We used differential phases obtained from observations carried out in the Hα absorption line of α Cep with the VEGA/CHARA interferometer at high spectral resolution, R=30000 to study the kinematics in the atmosphere of the star. We studied the influence of the gravity darkening effect (GDE) on the determination of the PA of the rotation axis of α Cep and determined its value, PA=-157+17°–10°. We conclude that the GDE has a weak influence on the dispersed phases. We showed that the surface differential rotation can have a rather strong influence on the determination of the gravity darkening exponent. A new method of determining the inclination angle of the stellar rotational axis is suggested. We conclude that differential phases obtained with spectro-interferometry carried out on the Hα line can in principle lead to an estimate of the stellar inclination angle i. However, to determine both i and the differential rotation parameter α, lines free from the Stark effect and that have collision-dominated source functions are to be preferred.

Abstract Copyright:

Journal keyword(s): techniques: high angular resolution - techniques: interferometric - stars: individual: α Cephei - stars: rotation - stars: individual: Alderamin

Simbad objects: 4

goto Full paper

goto View the reference in ADS

Number of rows : 4

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2019
#notes
1 * alf Eri Be* 01 37 42.84548 -57 14 12.3101 -0.36 0.30 0.46 0.49 0.60 B6Vpe 437 0
2 * alf Aql dS* 19 50 46.99855 +08 52 05.9563 1.07 0.98 0.76 0.62 0.49 A7Vn 805 0
3 * alf Cep PM* 21 18 34.77233 +62 35 08.0681 2.770 2.680 2.460 2.22 2.11 A8Vn 338 0
4 * alf PsA ** 22 57 39.04625 -29 37 20.0533 1.31 1.25 1.16 1.11 1.09 A4V 1097 3

    Equat.    Gal    SGal    Ecl

To bookmark this query, right click on this link: simbad:objects in 2013A&A...555A.100D and select 'bookmark this link' or equivalent in the popup menu


2019.10.13-23:37:59

© Université de Strasbourg/CNRS

    • Contact