Searching for Pulsation Signals in Low Mass Stars with TESS through Light Curve Analysis

Abstract

Asteroseismology is an important tool for probing the fundamental characteristics of pulsating stars. Stellar oscillations are influenced by internal pressure, temperature gradients, and the structure of convective zones. Therefore, studying these oscillations enhances our understanding of stellar interiors. Research has shown that high mass main sequence stars exhibit strong pulsations. Theoretical models predict that low mass stars including M dwarfs can also pulsate at shorter periods and lower amplitudes. However, previous Kepler and K2 missions failed to detect convincing pulsations in M dwarfs likely due to a combination of instrumental limitations and the intrinsic faintness of the signals. In this work, we aim to identify solar like pulsations in low mass stars, particularly M dwarfs, using the Transiting Exoplanet Survey Satellite (TESS) 20 second cadence data. The high cadence and improved photometric precision of 20 second cadence data provide our best current opportunity to detect these faint pulsations especially in the low frequency, low amplitude regime where they are expected to occur. We extracted and analyzed light curves from our target stars to identify and characterize noteworthy signals. After processing the data, we used Lomb Scargle periodograms, power spectrum, and threshold analysis to investigate the nature of these signals. Our analysis revealed a variety of phenomena, including stellar flares, eclipsing binaries, variable stars, previously uncatalogued pulsations from nearby higher mass stars, and strong rotational modulation signatures in many of our targets.