The pulsational behaviour of the rapidly oscillating Ap star HD 122970 during two photometric multisite campaigns
- Author(s)
- Gerald Handler, Werner Wolfgang Weiss, Ernst Paunzen, R R Shobbrook, Rafael Garrido, Joyce Ann Guzik, A Hempel, M B Moalusi, T E Beach, R Medupe, Francois Chagnon, Jaymie M. Matthews, Peter Reegen, Thomas Granzer
- Abstract
We undertook two time-series photometric multisite campaigns for the rapidly oscillating Ap star HD 122970. The first one, conducted in 1998, resulted in 119 h of data and in the detection of three pulsation frequencies. The presence of possible further modes which held the promise of deriving a mode identification motivated a second worldwide campaign in the year 2001. This second campaign resulted in 203 h of measurement, but did not reveal further modes. Rather, one of the previously detected signals disappeared. The two modes common to both data sets have different spherical degree. They also showed slight frequency modulation, and one of them varied in amplitude as well. Possible causes of the latter behaviour include intrinsic instability of the pulsation spectrum or precession of the pulsational axis and orbital motion in a binary system. Frequency analysis of the Hipparcos observations of the star did not allow us to determine the stellar rotation period. The amplitude and phase behaviour of the two modes of HD 122970 in the Strošmgren uvby bands is quite similar to that observed for other roAp stars.
- Organisation(s)
- Department of Astrophysics
- External organisation(s)
- Instituto de Astrofísica de Andalucía (CSIC), Los Alamos National Laboratory, South African Astronomical Observatory (SAAO), University of British Columbia (UBC), Leibniz-Institut für Astrophysik Potsdam, Australian National University, University of Cape Town, North-West University, University of New Mexico
- Journal
- Monthly Notices of the Royal Astronomical Society
- Volume
- 330
- Pages
- 153-159
- No. of pages
- 7
- ISSN
- 0035-8711
- DOI
- https://doi.org/10.1046/j.1365-8711.2002.05056.x
- Publication date
- 2002
- Peer reviewed
- Yes
- Austrian Fields of Science 2012
- 103003 Astronomy
- Portal url
- https://ucrisportal.univie.ac.at/en/publications/b53f07fc-eed3-4957-bf68-1306f74d216b