Very recent measurements of stellar winds are used to update relations between winds and coronal activity. New wind constraints include an upper limit of Mdot<0.1 Mdot_sun for Tau Ceti (G8 V), derived from a nondetection of astrospheric H I Lyman-alpha absorption. This upper limit is reported here for the first time, and represents the weakest wind constrained using the astrospheric absorption technique. A high mass loss rate measurement of Mdot=10 Mdot_sun for Delta Pav (G8 IV) from astrospheric Lyman-alpha absorption suggests stronger winds for subgiants than for main sequence stars of equivalent activity. A very low mass-loss rate of Mdot~0.06 Mdot_sun recently estimated for GJ 436 (M3 V) from Lyman-alpha absorption from an evaporating exoplanetary atmosphere implies inactive M dwarfs may have weak winds compared with GK dwarfs of similar activity.
@article{arxiv.1809.01109,
title = {Implications of Recent Stellar Wind Measurements},
author = {Brian E. Wood},
journal= {arXiv preprint arXiv:1809.01109},
year = {2018}
}
Comments
To appear in the Proceedings of the 17th Annual Astrophysics Conference: Dissipative and Heating Processes in Collisionless Plasma: The Solar Corona, the Solar Wind, and the Interstellar Medium, IOP Conference Series