Volume 479, Number 3, March I 2008
|Page(s)||845 - 848|
|Section||Stellar structure and evolution|
|Published online||09 January 2008|
Recovery of p-modes in the combined 2004-2005 MOST observations of Procyon*
Department of Physics and Astronomy, Western Kentucky University, 1906 College Heights Blvd., 11077, Bowling Green, KY 42101-1077, USA e-mail: email@example.com
Accepted: 31 December 2007
Aims.Procyon A, a bright F5 IV-V Sun-like star, is justifiably regarded as a prime asteroseismological target. This star was repeatedly observed by MOST, a specialized microsatellite providing long-term, non-interrupted broadband photometry of bright targets. So far, the widely anticipated p-modes eluded direct photometric detection, though numerous independent approaches hinted for the presence of signals in the f ~ 0.5-1.5 mHz range.
Methods.Implementation of an alternative approach in data processing, as well as combination of the MOST data from 2004 and 2005 (264 189 measurements in total) helps to reduce the instrumental noise affecting previous reductions, bringing the detection limit down to ~5.5 part-per-million in the f = 0.8-1.2 mHz range.
Results.This enabled us to cross-identifiy 16 p-mode frequencies (though not their degrees) which were previously detected via high-precision radial velocity measurements, and provides an estimate of the large spacing, = 0.0540 mHz at f ~ 1 mHz. The relatively low average amplitude of the detected modes, a = 5.8±0.6 ppm, closely matches the amplitudes inferred from the ground-based spectroscopy and upper limits projected from WIRE photometry. This also explains why such low-amplitude signals eluded the direct-detection approach which exclusively relied on the MOST 2004 (or 2005) data processed by a standard pipeline.
Key words: stars: oscillations / stars: individual: Procyon A / techniques: photometric / methods: data analysis
© ESO, 2008
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.