X-ray Emission from the Exoplanet Hosting LTT 1445 Triple Star System

Abstract

JWST will be able to observe the atmospheres of rocky planets transiting nearby M dwarfs. The M dwarf triple star system LTT 1445, at a distance of 6.86 pc, hosts some of the nearest rocky terrestrial planets. These planets most likely orbit the M 3.5V star LTT 1445A. During a 28.6 ksec Chandra ACIS-S3 observation we have i) spatially resolved and detected all three stars in the LTT 1445 system, ii) measured the X-ray luminosity of the individual stars, including LTT 1445A, for the first time, iii) studied the flux variability of the X-ray sources and found strong variability from the A and C components, and iv) investigated how the coronal luminosities, temperatures and volume emission measures vary at different activity levels. Combining these X-ray data with upcoming HST ultraviolet observations will allow a differential emission measure (DEM) estimation of the star's EUV spectrum, thereby facilitating modeling of the rocky planets' atmospheres.

arXiv comment18 pages, 4 figures. Accepted to The Astronomical Journal (2022 September 1)

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Cited by in corpus (5)

• The MUSCLES Extension for Atmospheric and Transmission Spectroscopy: UV and X-ray Host-star Observations for JWST ERS & GTO Targets
• Ground-based Optical Transmission Spectroscopy of the Nearby Terrestrial Exoplanet LTT 1445Ab
• High-energy spectra of LTT 1445A and GJ 486 reveal flares and activity
• An HST Transmission Spectrum of the Closest M-Dwarf Transiting Rocky Planet LTT 1445Ab
• X-ray variability of the triplet star system LTT1445 and evaporation history of the exoplanets around its A component