0 Assigned ID: 2017 ----- Attempting Submission 1 (Fri Apr 09 16:45:22 GMT 2021) ----- In recent years, studies of the habitability of terrestrial planets around low-mass stars have been incorporating the effects of far-ultraviolet (FUV) stellar flares into their analysis. The FUV flux from flares can drive the breakdown of anoxic biosignatures, while also altering atmospheric compositions. However, due to the scarcity of measured FUV flare rates for individual stars of interest, many studies rely on using empirical flare models to extrapolate white-light flare rates measured with TESS to the FUV. Such extrapolations have not been rigorously tested for low-mass stars at any age or activity, leaving open the possibility that habitability studies may currently underestimate FUV flare rates by factors of tens to hundreds. The HST archive contains STIS and COS FUV TIME-TAG data for 89 M stars that have been, or will shortly be, observed in the short cadence mode of TESS. These stars have ages ranging from pre-main sequence to field age, and include stars associated with the 45 and 625 Myr Tuc-Hor and Hyades open clusters. We propose to combine the archival HST and TESS data of these stars to test the FUV predictions of habitability studies that rely on white-light flare rates. We will measure the average white-light and FUV flare rates for each group of stars in our sample. By combining our white-light rates with the empirical flare models used by current habitability studies to predict FUV flare rates, we will be able to directly test their accuracy in modelling the FUV activity of low-mass stars from TESS data alone. The results of these tests will provide a vital resource for future habitability studies of terrestrial planets around low-mass stars. Dr James A. G. Jackman (Arizona State University) is an expert on white-light and UV flares from low-mass stars. They are proficient in the detection and characterisation of flares in high cadence photometry, having led six first-author papers on the topic since 2018. He will lead the data reduction, analysis and publication efforts. Dr R. O. Parke Loyd (Arizona State University) has expertise in the UV emission of stars, in particular FUV flares and their energetics and impacts on planetary atmospheres. He is proficient in the reduction and analysis of HST data, having led five first-author papers using such data since 2014 and the Cycle 27 AR proposal ID #15803. Dr Loyd will assist in the data reduction and analysis for this program. Dr Evgenya Shkolnik is an expert in the both the quiescent and flaring FUV emission of low-mass stars and its impact on the habitability of terrestrial planets around such stars. They are the PI of the Cycle 24 HST proposal #14784, which studied the UV evolution of early M stars. They will assist in the data reduction, data analysis, and publication efforts. Tyler Richey-Yowell (Arizona State University) is a graduate student working with Dr Shkolnik and is an expert on the UV environments of low-mass stars, and the implications of FUV emission on exoplanet formation and habitability. They are the PI of the Cycle 27 proposal #15955, which studied the UV evolution of K stars. They will assist in the data reduction, data analysis, and publication efforts. Stellar Physics and Stellar Types Exoplanets and Exoplanet Formation 0 Regular false false true false false SUPPORTED