Contemporaneous Observations of Hα Luminosities and Photometric Amplitudes for M dwarfs

Many M dwarfs are known to have strong magnetic fields, but we are still unsure about the properties of their starspots and the origin of their magnetic dynamos. Both starspots and magnetic activity are related to the surface magnetic field, so one means of examining magnetic phenomena is to connect photometric variability (driven by starspots) and magnetic activity. We studied 56 M dwarfs with periods of 0.1 to 27 days. We present time-series optical photometry from the Transiting Exoplanet Survey Satellite (TESS) and contemporaneous optical spectra obtained using the Ohio State MultiObject Spectrograph (OSMOS) on the MDM 2.4m telescope in Arizona. Using the TESS light curves, we measure rotation periods and photometric amplitudes. From the OSMOS spectra, we calculate the equivalent width of Hα. We find a loose positive correlation between Hα luminosity and photometric amplitudes for stars in the saturated regime of the rotation-activity relation (Pearson correlation coefficient \(0.664^{+0.023}_{-0.026}\)). We additionally see short term variability in Hα equivalent widths and enhancement from flares