Naslov
Pulsations of the Oe Star zeta Ophiuchi from MOST Satellite Photometry and Ground-based Spectroscopy

Autori
Walker, G. A. H. ; Kuschnig, R. ; Matthews, J. M. ; Reegen, P. ; Kallinger, T. ; Kambe, E. ; Saio, H. ; Harmanec, P. ; Guenther, D. B. ; Moffat, A. F. J. ; Rucinski, S. M. ; Sasselov, D. ; Weiss, W. W. ; Bohlender, D. A. ; Božić, Hrvoje ; Hashimoto, O. ; Koubský, P. ; Mann, R. ; Ruždjak, Domagoj ; Škoda, P. ; Šlechta, M. ; Sudar, Davor ; Wolf, M. ; Yang, S.

Izvornik
The Astrophysical journal (0004-637X) 623 (2005), 2; L145-L148

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
Line: Profiles; Stars: Early-Type; Stars: Emission-Line; Be; Stars: Individual: Constellation Name: zeta Ophiuchi; Stars: Oscillations; Stars: Rotation

Sažetak
Twenty-four days of highly precise Microvariability and Oscillations of Stars (MOST) satellite photometry obtained in mid-2004 of the rapidly rotating O9.5 V star zeta Oph have yielded at least a dozen significant oscillation frequencies between 1 and 10 cycles day-1, clearly indicating its relationship to beta Cephei variables. Eight periods were found in He I alpha 4922 and H beta line profile variations (LPV) of which six coincide with those from the MOST photometry. This unique photometric and spectroscopic detection of radial and nonradial pulsations leads to a plausible model in which high l-modes are excited when their frequencies in the corotating frame are similar to those of low-order radial modes. We propose that the dominant photometric 4.6 hr period (f1) corresponds to a radial first overtone excited by the kappa -mechanism associated with the Fe opacity bump. No unambiguous rotational period can be identified in either the light curve or the LPV.

Izvorni jezik
Engleski

Znanstvena područja
Fizika

POVEZANOST RADA