In the Quest for Pulsation in Main-sequence M Dwarf Stars from TESS Observations

Abstract We report the results of an extensive survey in the quest for pulsation signatures in main-sequence M dwarf stars, based on observations acquired by the TESS space mission. Using TESS 2 minutes cadence light curves from a sample of 56,217 targets, observed in Sectors 1–89 of the mission, we identify low-amplitude modulation for 15 targets, with period values ranging from 0.0421 days (∼1.01 hr) to 0.1148 days (∼2.75 hr). These periodicities fall within the predicted range for pulsations in low-mass main-sequence M-type stars. For instance, for low-mass stars, pulsation is a fundamental observable for solving persistent discrepancies between observed and predicted parameters (e.g., radii, masses). Nevertheless, the detection of a pulsating M dwarf has not yet been achieved despite solid theoretical predictions. Among the 15 targets referred to, only one star, the dwarf MGC 2543, appears to be a good candidate for a pulsator, despite a mean modulation amplitude of 1647 μ mag, which is higher than the predicted values.