2009A&A...508..409A


C.D.S. - SIMBAD4 rel 1.7 - 2021.02.24CET19:12:01

2009A&A...508..409A - Astronomy and Astrophysics, volume 508, 409-419 (2009/12-2)

Collective pulsational velocity broadening due to gravity modes as a physical explanation for macroturbulence in hot massive stars.

AERTS C., PULS J., GODART M. and DUPRET M.-A.

Abstract (from CDS):

We aimed at finding a physical explanation for the occurrence of macroturbulence in the atmospheres of hot massive stars, a phenomenon found in observations for more than a decade but that remains unexplained. We computed time series of line profiles for evolved massive stars broadened by rotation and by hundreds of low-amplitude nonradial gravity-mode pulsations which are predicted to be excited for evolved massive stars. In general, line profiles based on macrotubulent broadening can mimic those subject to pulsational broadening. In several cases, though, good fits require macroturbulent velocities that pass the speed of sound for realistic pulsation amplitudes. Moreover, we find that the rotation velocity can be seriously underestimated by using a simple parameter description for macroturbulence rather than an appropriate pulsational model description to fit the line profiles. We conclude that macroturbulence is a likely signature of the collective effect of pulsations. We provide line diagnostics and their typical values to decide whether or not pulsational broadening is present in observed line profiles, as well as a procedure to avoid an inaccurate estimation of the rotation velocity.

Abstract Copyright:

Journal keyword(s): line: profiles - techniques: spectroscopic - stars: atmospheres - supergiants - stars: early-type - stars: variables: general

Simbad objects: 6

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Number of rows : 6

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2021
#notes
1 NAME Magellanic Clouds GrG 03 00 -71.0           ~ 5854 1
2 * ksi01 CMa bC* 06 31 51.3663578 -23 25 06.318090 3.10 4.09 4.33 4.45 4.72 B0.7IV 302 0
3 HD 163889 * 17 59 05.9198915000 -15 13 05.210758493   9.04 8.97     B8II 6 0
4 HD 163899 Pu* 17 59 56.3484038559 -33 53 26.958683912 7.88 8.51 8.31 9.17 8.59 B2Ib/II 45 0
5 HD 180642 bC* 19 17 14.8041207725 +01 03 33.905280608 7.83 8.47 8.29     B1.5II-III 93 0
6 V* BW Vul bC* 20 54 22.3949148537 +28 31 19.182736153 5.47 6.40 6.54     B2IIIv 286 0

    Equat.    Gal    SGal    Ecl

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2021.02.24-19:12:01

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