Living with a Red Dwarf: Rotation and X-ray and Ultraviolet Properties of the Halo Population Kapteyn's Star

Abstract

As part of Villanova's Living with a Red Dwarf program, we have obtained UV, X-ray and optical data of the Population II red dwarf -- Kapteyn's Star. Kapteyn's Star is noteworthy for its large proper motions and high RV of ~+245 km s^-1. As the nearest Pop II red dwarf, it serves as an old age anchor for calibrating Activity/Irradiance-Rotation-Age relations, and an important test bed for stellar dynamos and the resulting X-ray -- UV emissions of slowly rotating, near-fully convective red dwarf stars. Adding to the notoriety, Kapteyn's Star has recently been reported to host two super-Earth candidates, one of which (Kapteyn b) is orbiting within the habitable zone (Anglada-Escude et al. 2014a, 2015). However, Robertson et al. (2015) questioned the planet's existence since its orbital period may be an artifact of activity, related to the star's rotation period. Because of its large Doppler-shift, measures of the important, chromospheric H I Lyman-alpha 1215.67A emission line can be reliably made, because it is mostly displaced from ISM and geo-coronal sources. Lyman-alpha emission dominates the FUV region of cool stars. Our measures can help determine the X-ray--UV effects on planets hosted by Kapteyn's Star, and planets hosted by other old red dwarfs. Stellar X-ray and Lyman-alpha emissions have strong influences on the heating and ionization of upper planetary atmospheres and can (with stellar winds and flares) erode or even eliminate planetary atmospheres. Using our program stars, we have reconstructed the past exposures of Kapteyn's Star's planets to coronal -- chromospheric XUV emissions over time.

40 pages, 4 tables, 8 figures; accepted for publication in the Astrophysical Journal

References in corpus (18)

• Improved Age Estimation for Solar-Type Dwarfs Using Activity-Rotation Diagnostics
• Ages and fundamental properties of Kepler exoplanet host stars from asteroseismology
• On the age of the $\beta$ Pictoris moving group
• Chromospheric Activity, Rotation, and Rotational Braking in M and L Dwarfs
• An ancient extrasolar system with five sub-Earth-size planets
• Effect of UV Radiation on the Spectral Fingerprints of Earth-like Planets Orbiting M dwarfs
• Bayesian search for low-mass planets around nearby M dwarfs. Estimates for occurrence rate based on global detectability statistics
• An Activity-Rotation Relationship and Kinematic Analysis of Nearby Mid-to-Late-type M Dwarfs
• M Dwarfs in SDSS Stripe 82: Photometric Light Curves and Flare Rate Analysis
• The HARPS search for southern extra-solar planets: XIV. Gl 176b, a super-Earth rather than a Neptune, and at a different period
• Tidal heating of Earth-like exoplanets around M stars: Thermal, magnetic, and orbital evolutions
• Two planets around Kapteyn's star : a cold and a temperate super-Earth orbiting the nearest halo red-dwarf
• Stellar activity mimics a habitable-zone planet around Kapteyn's star
• The HARPS search for southern extra-solar planets XXXV. Planetary systems and stellar activity of the M dwarfs GJ 3293, GJ 3341, and GJ 3543
• Ultra-high-time Resolution Observations of Radio Bursts on AD Leonis
• PROMPT Observations of the Early-Time Optical Afterglow of GRB 060607A
• No evidence for activity correlations in the radial velocities of Kapteyn's star
• The Kapteyn moving group is not tidal debris from $\omega$ Centauri

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