2018A&A...613L...4V


C.D.S. - SIMBAD4 rel 1.7 - 2019.11.17CET17:32:53

2018A&A...613L...4V - Astronomy and Astrophysics, volume 613, L4-4 (2018/5-1)

Rotation of the asymptotic giant branch star R Doradus.

VLEMMINGS W.H.T., KHOURI T., DE BECK E., OLOFSSON H., GARCIA-SEGURA G., VILLAVER E., BAUDRY A., HUMPHREYS E.M.L., MAERCKER M. and RAMSTEDT S.

Abstract (from CDS):

High-resolution observations of the extended atmospheres of asymptotic giant branch (AGB) stars can now directly be compared to the theories that describe stellar mass loss. Using Atacama Large Millimeter/submillimeter Array (ALMA) high angular resolution (30x42mas) observations, we have for the first time resolved stellar rotation of an AGB star, R Dor. We measure an angular rotation velocity of ωRsini=(3.5±0.3)x10–9rad/s, which indicates a rotational velocity of |υrotsini|=1.0±0.1km/s at the stellar surface (R*=31.2mas at 214GHz). The rotation axis projected on the plane of the sky has a position angle Φ=7±6°. We find that the rotation of R Dor is two orders of magnitude faster than expected for a solitary AGB star that will have lost most of its angular momentum. Its rotational velocity is consistent with angular momentum transfer from a close companion. As a companion has not been directly detected, we suggest R Dor has a low-mass, close-in companion. The rotational velocity approaches the critical velocity, set by the local sound speed in the extended envelope, and is thus expected to affect the mass-loss characteristics of R Dor.

Abstract Copyright: © ESO 2018

Journal keyword(s): stars: AGB and post-AGB - stars: rotation

Simbad objects: 2

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Number of rows : 2

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* R Dor AB* 04 36 45.59127 -62 04 37.7974 7.84 6.98 5.40 2.71 -0.44 M8III:e 272 0
2 V* V Hya C* 10 51 37.2614060865 -21 15 00.339641553   12.23 6.80     C-N:6 335 0

    Equat.    Gal    SGal    Ecl

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2019.11.17-17:32:53

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