SMEI observations of previously unseen pulsation frequencies in gamma Doradus

TL;DR

This study used SMEI photometric data to identify three new pulsation frequencies in gamma Doradus, expanding the known oscillation modes of this star through detailed periodogram analysis.

Contribution

It reports the discovery of three previously unobserved pulsation frequencies in gamma Doradus using long-term SMEI photometry, revealing more complex stellar oscillation behavior.

Findings

Three new frequencies at 1.39, 1.87, and 2.743 cycles per day identified.

Two frequencies likely represent additional pulsation modes.

One frequency may be a combination frequency.

Abstract

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.