Y. P. Elsworth — Page 3

arXiv2008

SMEI observations of previously unseen pulsation frequencies in gamma Doradus

Aims: As g-mode pulsators, gamma-Doradus-class stars may naively be expected to show a large number of modes. Taking advantage of the long photometric time-series generated by the Solar Mass Ejection Imager (SMEI) instrument, we have studied the star gamma Doradus to determine whether any other modes than the three already known are present at observable amplitude. Methods: High-precision photometric data from SMEI taken between April 2003 and March 2006 were subjected to periodogram analysis with the PERIOD04 package. Results: We confidently determine three additional frequencies at 1.39, 1.87, and 2.743 cycles per day. These are above and beyond the known frequencies of 1.320, 1.364, and 1.47 cycles per day. Conclusions: Two of the new frequencies, at 1.39 and 1.87 cycles per day, are speculated to be additional modes of oscillation, with the third frequency at 2.743 cycles per day a possible combination frequency.

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arXiv2008

Reliability of P mode event classification using contemporaneous BiSON and GOLF observations

We carried out a comparison of the signals seen in contemporaneous BiSON and GOLF data sets. Both instruments perform Doppler shift velocity measurements in integrated sunlight, although BiSON perform measurements from the two wings of potassium absorption line and GOLF from one wing of the NaD1 line. Discrepancies between the two datasets have been observed. We show,in fact, that the relative power depends on the wing in which GOLF data observes. During the blue wing period, the relative power is much higher than in BiSON datasets, while a good agreement has been observed during the red period.

astro-ph↗