HST part of joint Chandra/HST program -1251773546 Assigned ID: 7869 ----- Attempting Submission 1 (Wed Sep 09 21:01:39 GMT 2026) ----- (Joint Chandra/HST proposal: abstract from Chandra part) The magnetically controlled hot (1-10 MK) coronae of late-type stars radiate directly in X-rays, and indirectly in FUV emissions; and are variable on time scales of ks (flares) to decades (magnetic dynamo cycles). The behavior of the high-energy emissions is valued by coronal-formation theorists, as well as exoplanet researchers for "space weather" impacts. Only less than a dozen cool stars have sufficiently good time series at X-ray and FUV energies to document these variability modes, and several are dMe stars dominated by stochastic flaring. This proposal is a multi-year, joint Chandra/HST study of 3 key coronal binaries -- Alpha Centauri, Xi Bootis, and 70 Ophiuchi -- to further explore the varied variability landscape. PI Ayres has extensive experience with HST instruments in general and the STIS spectrograph in particular. Stellar Physics and Stellar Types 6 false true false false false false false true SECONDARY CHANDRA 28200140 false SUPPORTED This object was generated by the targetselector and retrieved from the SIMBAD database. SIMBAD listed proper motion for this target. When retrieving targets with PM from SIMBAD, APT requests the coordinates be calculated with an epoch of the year 2000. Do not modify this epoch. Always review coordinates using the Target Confirmation tool, which graphically displays the PM. J2000 J2000 This object was generated by the targetselector and retrieved from the SIMBAD database. SIMBAD listed proper motion for this target. When retrieving targets with PM from SIMBAD, APT requests the coordinates be calculated with an epoch of the year 2000. Do not modify this epoch. Always review coordinates using the Target Confirmation tool, which graphically displays the PM. J2000 J2000 This object was generated by the targetselector and retrieved from the SIMBAD database. SIMBAD listed proper motion for this target. When retrieving targets with PM from SIMBAD, APT requests the coordinates be calculated with an epoch of the year 2000. Do not modify this epoch. Always review coordinates using the Target Confirmation tool, which graphically displays the PM. J2000 J2000 This object was generated by the targetselector and retrieved from the SIMBAD database. SIMBAD listed proper motion for this target. When retrieving targets with PM from SIMBAD, APT requests the coordinates be calculated with an epoch of the year 2000. Do not modify this epoch. Always review coordinates using the Target Confirmation tool, which graphically displays the PM. J2000 J2000 STIS/FUV-MAMA Spectroscopic No No E140M 1425 STIS/FUV-MAMA Spectroscopic No No E140M 1425 STIS/FUV-MAMA Spectroscopic No No E140M 1425 The scheduling data was generated by CASM 34.2. CASM was run in Phase I mode. STIS/FUV-MAMA Spectroscopic No No E140M 1425