SDSS J160043.6+074802.9: a very rapid sdO pulsator

Autor: David Kilkenny, Petri Vaisanen, David A. H. Buckley, R. S. Stobie, Jeffrey W. Percival, Brian Warner, E. B. Burgh, M. Still, Patrick A. Woudt, Charles Copley, Kenneth H. Nordsieck, Nicola Loaring, Alexei Y. Kniazev, D. O'Donoghue, E. Zietsman
Rok vydání: 2006
Předmět:
Zdroj: Monthly Notices of the Royal Astronomical Society. 371:1497-1502
ISSN: 1365-2966
0035-8711
Popis: We report the serendipitous discovery of the Sloan Digital Sky Survey star, SDSS J160043.6+074802.9 to be a very rapid pulsator. The variation is dominated by a frequency near 8380 microHz (period = 119.33 s) with a large amplitude (0.04 mag) and its first harmonic at 16760 microHz (59.66 s; 0.005 mag). In between these frequencies, we find at least another 8 variations with periods between 62 and 118 seconds and amplitudes between about 0.007 and 0.003 mag; weaker oscillations might also be present. Preliminary spectrograms from the performance verification phase of the Southern African Large Telescope indicate that SDSS J160043.6+074802.9 is a spectroscopic binary consisting of an sdO star and a late-type main-sequence companion. This makes it the first unambiguous detection of such an sdO star to pulsate, and certainly the first found to exhibit multi-frequency variations.
7 pages, 6 figures (figure 4 at reduced resolution, original available on request). Accepted for publication in MNRAS
Databáze: OpenAIRE
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