We report the results of our HST snapshot survey with the ACS HRC PR200Lprism, designed to measure the near-UV emission in a sample of nearby M dwarfs.33 stars were observed, spanning the mass range from 0.1 - 0.6 solar masses(T_eff ~ 2200K - 4000K) where the UV energy distributions vary widely betweenactive and inactive stars. These observations provide much-needed constraintson models of the habitability zone and the atmospheres of possible terrestrialplanets orbiting M dwarf hosts, and will be useful in refining the targetselection for future space missions such as TPF. We compare our data with a newgeneration of M dwarf atmospheric models and discuss their implication for thechromospheric energy budget. These NUV data will also be valuable inconjunction with existing optical, FUV and X-ray data to explore unansweredquestions regarding the dynamo generation and magnetic heating in low-massstars.
展开▼
