MOST found evidence for solar-type oscillations in the K2 giant star HD20884

Abstract

We found evidence for radial p-modes and nonradial mixed modes in the oscillation spectrum of the K giant HD 20884 based on 20.6 days of nearly continuous high-precision photometry obtained by the Canadian microsatellite MOST Oscillation frequencies range from 5-31 μHz (periods of about 2.3 d - 9 hr) with luminosity amplitudes between about 300 and 950 ppm and mode lifetimes exceeding 10 days are indicated. The mode identifications are based on searches of a large grid of models for a best fit to the frequencies and temperature of HD 20884. The latter is better constrained now by spectroscopy obtained at the David Dunlap Observatory as part of this work. Based on data from the MOST (Microvariability {&} Oscillation of STars) satellite, a Canadian Space Agency mission jointly operated by Dynacon, Inc., the University of Toronto Institute of Aerospace Studies, and the University of British Columbia, with assistance from the University of Vienna, Austria.