253 citations · 2.9k across the 51 of their papers we have counts for
9 papers · 1 filter
The Evolution of Stellar Rotation and the hydrogen atmospheres of habitable-zone Terrestrial Planets
C. P. Johnstone, M. Güdel, A. Stökl +7
Terrestrial planets formed within gaseous protoplanetary disks can accumulate significant hydrogen envelopes. The evolution of such an atmosphere due to XUV driven evaporation depe…
Stellar magnetic activity and their influence on the habitability of exoplanets
T. Lüftinger, M. Güdel, C. P. Johnstone
Stellar magnetism, explorable via polarimetry, is a crucial driver of activity, ionization, photodissociation, chemistry and winds in stellar environments. Thus it has an important…
Short-period stellar activity cycles with Kepler photometry
Oleksiy V. Arkhypov, Maxim L. Khodachenko, Helmut Lammer +3
We study the short-periodic component of stellar activity with a cycle periods Pcyc up to 1000 days using the Kepler mission photometry of fast-rotating (rotational periods from 1…
The Coronal Temperatures of Low-Mass Main-Sequence Stars
Colin P. Johnstone, Manuel Güdel
Aims. We study the X-ray emission of low-mass main-sequence stars to derive a reliable general scaling law between coronal temperature and the level of X-ray activity. Methods. We…
The Extreme Ultraviolet and X-Ray Sun in Time: High-Energy Evolutionary Tracks of a Solar-Like Star
Lin Tu, Colin P. Johnstone, Manuel Güdel +1
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…
Stellar wind induced soft X-ray emission from close-in exoplanets
K. G. Kislyakova, L. Fossati, C. P. Johnstone +3
In this paper, we estimate the X-ray emission from close-in exoplanets. We show that the Solar/Stellar Wind Charge Exchange Mechanism (SWCX) which produces soft X-ray emission is v…
Stellar Winds on the Main-Sequence I: Wind Model
C. P. Johnstone, M. Güdel, T. Lüftinger +2
Aims: We develop a method for estimating the properties of stellar winds for low-mass main-sequence stars between masses of 0.4 and 1.1 solar masses at a range of distances from th…
Stellar Winds on the Main-Sequence II: the Evolution of Rotation and Winds
C. P. Johnstone, M. Güdel, I. Brott +1
Aims: We study the evolution of stellar rotation and wind properties for low-mass main-sequence stars. Our aim is to use rotational evolution models to constrain the mass loss rate…
Colliding Winds in Low-Mass Binary Star Systems: wind interactions and implications for habitable planets
C. P. Johnstone, A. Zhilkin, E. Pilat-Lohinger +3
Context. In binary star systems, the winds from the two components impact each other, leading to strong shocks and regions of enhanced density and temperature. Potentially habitabl…