Solar-like Oscillations in the G2 Subgiant β Hydri from Dual-Site Observations
Abstract
We have observed oscillations in the nearby G2 subgiant star β Hyi using high-precision velocity observations obtained over more than a week with the HARPS and UCLES spectrographs. The oscillation frequencies show a regular comb structure, as expected for solar-like oscillations, but with several l=1 modes being strongly affected by avoided crossings. These data, combined with those we obtained five years earlier, allow us to identify 28 oscillation modes. By scaling the large-frequency separation from the Sun, we measure the mean density of β Hyi to an accuracy of 0.6%. The amplitudes of the oscillations are about 2.5 times solar and the mode lifetime is 2.3 days. A detailed comparison of the mixed l=1 modes with theoretical models should allow a precise estimate of the age of the star.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- July 2007
- DOI:
- arXiv:
- arXiv:astro-ph/0703747
- Bibcode:
- 2007ApJ...663.1315B
- Keywords:
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- Stars: Individual: Constellation Name: β Hydri;
- Stars: Oscillations;
- Astrophysics
- E-Print:
- 13 pages, 14 figures, accepted by ApJ. Fixed minor typo (ref to Fig 14)