2012A&A...545A..59S


Query : 2012A&A...545A..59S

2012A&A...545A..59S - Astronomy and Astrophysics, volume 545A, 59-59 (2012/9-1)

The relationship between γ Cassiopeiae's X-ray emission and its circumstellar environment. II. Geometry and kinematics of the disk from MIRC and Vega instruments on the CHARA array.

STEE P., DELAA O., MONNIER J.D., MEILLAND A., PERRAUT K., MOURARD D., CHE X., SCHAEFER G.H., PEDRETTI E., SMITH M.A., LOPES DE OLIVEIRA R., MOTCH C., HENRY G.W., RICHARDSON N.D., BJORKMAN K.S., BUECKE R., POLLMANN E., ZOREC J., GIES D.R., TEN BRUMMELAAR T., McALISTER H.A., TURNER N.H., STURMANN J., STURMANN L. and RIDGWAY S.T.

Abstract (from CDS):

γ Cas is thought to be the prototype of classical Be stars and is the most studied object among this group. However, as for all Be stars, the origin and the physics of its circumstellar disk responsible for the observed near IR-excess, emission lines, and peculiar X-ray emission is still being debated. We constrain the geometry and kinematics of its circumstellar disk from the highest spatial resolution ever achieved on this star. This investigation is a part of a large multi-technique observing campaign to obtain the most complete picture of γ Cas which emphasizes the relation of the circumstellar environment to the star's X-ray flux. We present new observations in the near infrared (MIRC) and in the visible (VEGA) obtained with the CHARA interferometer. The VEGA instrument allows us to not only obtain a global disk geometry but also spectrally dispersed visibility modulus and phases within the Hα emission line, which enables us to study the kinematics within γ Cas's disk. We obtain a disk extension in the nearby Hα continuum of 1.72 stellar diameter and 1.86 stellar diameter in the H band at 1.65 µm assuming a Gaussian disk model but also compatible with an elliptical ring model with a minor internal diameter of 1.38 stellar diameter in H. For the first time we demonstrate that the rotation mapped by the emission in the Hα line within the disk of γ Cas and up to 10R* is Keplerian. These observations have pushed the size of the disk to greater proportions. γ Cas was also confirmed to be a nearly critical rotator. The disk imaging gives neither indication of a 1-arm spiral feature nor evidence of a secondary star reinforcing the interpretation that the secondary is certainly a low-mass and low-luminosity star or a degenerate companion.

Abstract Copyright:

Journal keyword(s): techniques: interferometric - stars: emission-line, Be - stars: winds, outflows - circumstellar matter - binaries: close

Simbad objects: 12

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Number of rows : 12
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2022
#notes
1 * zet Cas Pu* 00 36 58.2841866 +53 53 48.867311 2.58 3.47 3.66 3.74 3.95 B2IV 436 0
2 * gam Cas Be* 00 56 42.5310945 +60 43 00.264089 1.18 2.29 2.39 2.32 2.40 B0.5IVpe 1171 2
3 * mu. And PM* 00 56 45.2090751570 +38 29 57.603377713 4.14 3.99 3.87 3.72 3.64 A6V 213 0
4 * tet Cas PM* 01 11 06.1622468 +55 08 59.647259 4.630 4.510 4.330 4.16 4.09 A7V 194 0
5 * alf Eri Be* 01 37 42.84548 -57 14 12.3101 -0.36 0.30 0.46 0.49 0.60 B6Vpe 457 0
6 * phi Per Be* 01 43 39.6379209 +50 41 19.432832 3.10 4.02 4.06 3.90 3.88 B1.5V:e-shell 551 0
7 * g Per * 02 02 18.1084057296 +54 29 15.145135980 4.64 4.96 5.04 5.01 5.06 B8III 97 0
8 * 36 Per PM* 03 32 26.2592647368 +46 03 24.701606568 5.71 5.73 5.32 4.91 4.69 F4III 109 0
9 * ome CMa Be* 07 14 48.6538664 -26 46 21.609714 2.90 3.64 3.82 3.80 3.90 B2.5Ve 341 0
10 * del Sco SB* 16 00 20.00528 -22 37 18.1431 1.30 2.20 2.32 2.36 2.49 B0.3IV 720 0
11 * alf Ara Be* 17 31 50.4915282 -49 52 34.122041 2.09 2.78 2.95 3.05 3.29 B2Vne 250 0
12 * 7 And PM* 23 12 33.0037993 +49 24 22.345507 4.85 4.81 4.52 4.23 4.07 F1V 149 0

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2022.09.30-21:48:43

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