OBSERVATIONAL EVIDENCE FOR A CORRELATION BETWEEN MACROTURBULENT BROADENING AND LINE-PROFILE VARIATIONS IN OB SUPERGIANTS
- Instituto de Astrofisica de Canarias, E-38200 La Laguna, Tenerife (Spain)
- Laboratoire AIM, CEA/DSM-CNRS-Universite Paris Diderot, CEA, IRFU, SAp, centre de Saclay, F-91191, Gif-sur-Yvette (France)
- Instituut voor Sterrenkunde, Katholieke Universiteit Leuven, Celestijnenlaan 200D, B-3001 Leuven (Belgium)
- Universitaetssternwarte Muenchen, Scheinerstr. 1, D-81679 Muenchen (Germany)
The spectra of O and B supergiants (Sgs) are known to be affected by a significant form of extra line broadening (usually referred to as macroturbulence) in addition to that produced by stellar rotation. Recent analyses of high-resolution spectra have shown that the interpretation of this line broadening as a consequence of large-scale turbulent motions would imply highly supersonic velocity fields in photospheric regions, making this scenario quite improbable. Stellar oscillations have been proposed as a likely alternative explanation. As part of a long-term observational project, we are investigating the macroturbulent broadening in O and B Sgs and its possible connection with spectroscopic variability phenomena and stellar oscillations. In this Letter, we present the first encouraging results of our project, namely, firm observational evidence for a strong correlation between the extra broadening and photospheric line-profile variations in a sample of 13 Sgs with spectral types ranging from O9.5 to B8.
- OSTI ID:
- 21452824
- Journal Information:
- Astrophysical Journal Letters, Vol. 720, Issue 2; Other Information: DOI: 10.1088/2041-8205/720/2/L174; ISSN 2041-8205
- Country of Publication:
- United States
- Language:
- English
Similar Records
THE THIRD SIGNATURE OF GRANULATION IN BRIGHT-GIANT AND SUPERGIANT STARS
Spectroscopic studies of O-type stars. VII. Rotational velocities V sin i and evidence for macroturbulent motions