0 Assigned ID: 957 ----- Attempting Submission 1 (Fri Apr 05 23:34:02 GMT 2019) ----- If the frequent, energetic flares of active stars are each accompanied by a coronal mass ejection (CME), the effect on stellar and planetary evolution could be strong. Every CME event carries mass and angular momentum away from the star, and each has the potential to impact and strip atmospheric gas from orbiting planets. Developing observational constraints on stellar CMEs is essential to assessing their true impact on stellar and planetary evolution. Such constraints are possible via the unique FUV capabilities of HST. In the FUV, photometry of the coronal Fe XXI 1354 A emission line can constrain the mass of CMEs that accompany flares through an effect known as coronal dimming. Coronal dimming is a direct result of the ejection of emitting coronal material, which leaves behind a dark void reliably detected in Sun-as-a-star observations as a drop in the disk-integrated emission of coronal lines. We propose a coronal dimming analysis of 10 h of high S/N archival COS G130M data of the K dwarf planet host Epsilon Eridani (Eps Eri), containing several flares to constrain the masses of associated CMEs. We will accompany this analysis with detailed MHD modeling of Eps Eri's corona to simulate the dimming in Fe XXI 1354 A emission following CMEs. This analysis will lay fundamental groundwork for future dedicated HST CME observations, develop theoretical tools for interpreting dimming signals through MHD analysis, and test whether CMEs could be a dominant contributor to Eps Eri's high observed mass loss rate. Expertise R. O. Parke Loyd, Kevin France, Allison Youngblood, have extensive experience analyzing data from HST COS and STIS, each having authored several papers utilizing data from these instruments in the past few years. PI Loyd recently published two publications covering analyses of flares detected in COS and STIS data, is PI on one HST program using COS, and is a co-I on 8 others using COS and STIS. Meng Jin is an expert in solar coronal physics and MHD modeling. Meng Jin has adapted the AWSoM code mentioned in the proposal to simulate solar CME dimmings. James Mason has published several recent papers on empirical relationships between solar dimmings and CME mass and energy. Christian Schneider is an expert in X-ray observations and data analysis. Jackie Villadsen is an expert in stellar CME searches, having conducted a search for CME-induced type II radio bursts as her thesis work. Evgenya Shkolnik, Adam Schneider, Joe Llama, Tahina Ramiaramanantsoa, and Tyler Richey-Yowell bring experience with stellar observations, including studies of stellar variability and lightcurve inversion. Roles Loyd will develop the data analysis toosl and carry out the analysis of the COS data to constrain dimming signals. Jin will adapt the AWSoM code to simulate CMEs and associated dimmings on Eps Eri. Christian Schneider will analyze contemporaneous archival X-ray data as to constrain coronal properties of Eps Eri (electron density and emission measure) within the same epoch as the bulk of the FUV observations. All others will primarily play advisory roles. Stellar Physics Planets and Planet Formation 0 Regular false false true false false SUPPORTED