The extreme ultraviolet and X-ray Sun in Time: High-energy evolutionary tracks of a solar-like star
Department of AstrophysicsUniversity of Vienna,
e-mail: firstname.lastname@example.org; email@example.com; firstname.lastname@example.org
2 Space Research Institute, Austrian Academy of Sciences, Schmiedlstrasse 6, 8042 Graz, Austria
Received: 20 March 2015
Accepted: 17 April 2015
Aims. We aim to describe the pre-main-sequence and main-sequence evolution of X-ray and extreme-ultaviolet radiation of a solar-mass star based on its rotational evolution starting with a realistic range of initial rotation rates.
Methods. We derive evolutionary tracks of X-ray radiation based on a rotational evolution model for solar-mass stars and the rotation-activity relation. We compare these tracks to X-ray luminosity distributions of stars in clusters with different ages.
Results. We find agreement between the evolutionary tracks derived from rotation and the X-ray luminosity distributions from observations. Depending on the initial rotation rate, a star might remain at the X-ray saturation level for very different time periods, from ≈10 Myr to ≈300 Myr for slow and fast rotators, respectively.
Conclusions. Rotational evolution with a spread of initial conditions leads to a particularly wide distribution of possible X-ray luminosities in the age range of 20–500 Myr, before rotational convergence and therefore X-ray luminosity convergence sets in. This age range is crucial for the evolution of young planetary atmospheres and may thus lead to very different planetary evolution histories.
Key words: Sun: evolution / stars: rotation / stars: activity / stars: solar-type / planets and satellites: atmospheres
© ESO, 2015