相关论文: Modeling Stellar Surface Features on Subgiant Star…
The accurate characterisation of the stellar magnetism of planetary host stars has been gaining momentum, especially in the context of transmission spectroscopy investigations of exoplanets. Indeed, the magnetic field regulates the amount…
Knowledge of the stellar parameters for the parent stars of transiting exoplanets is pre-requisite for establishing the planet properties themselves, and often relies on stellar evolution models. GJ 436, which is orbited by a transiting…
Context: Planets outside our solar system transiting their host star, i. e. those with an orbital inclination near 90 degree, are of special interest to derive physical properties of extrasolar planets. With the knowledge of the host star's…
We report observations from the Spitzer Space Telescope (SST) regarding the frequency of 24 micron excess emission toward sun-like stars. Our unbiased sample is comprised of 309 stars with masses 0.7-2.2 Msun and ages from <3 Myr to >3 Gyr…
TOI-3884~b is an unusual 6.4~R$_\oplus$ planet orbiting an M4 host, whose transits display large and persistent spot-crossing events. We used the \textit{Tierras} Observatory to monitor both the long-term photometric variability of TOI-3884…
We aim to characterise the magnetic field of the eclipsing binary CU Cnc. The determination of magnetic field parameters of this target enables comparisons with both observations of similar stars and theoretical predictions of the magnetic…
By combining rotation periods with spectroscopic determinations of projected rotation velocity, Jackson, Jeffries & Maxted (2009) have found that the mean radii for low-mass M-dwarfs in the young, open cluster NGC 2516 are larger than model…
Starspots and stellar flares are indicators of stellar magnetic activity.The magnetic energy stored around spots is thought to be the origin of flares, but the connection is not completely understood. To investigate the relation between…
Precise exoplanet characterization requires precise classification of exoplanet host stars. The masses of host stars are commonly estimated by comparing their spectra to those predicted by stellar evolution models. However,…
Stellar activity induces apparent radial velocity (RV) variations in late-type main-sequence stars that may hamper the detection of low-mass planets and the measurement of their mass. We use simultaneous measurements of the active planet…
We obtained J-, H- and JH-band photometry of known extrasolar planet transiting systems at the 2.1-m Kitt Peak National Observatory Telescope using the FLAMINGOS infrared camera between October 2008 and October 2011. From the derived…
We report the discovery of a transiting brown dwarf companion to KOI-205, a K0 main-sequence star, in a 11.720125-day period orbit. The transits were detected by the Kepler space telescope, and the reflex motion of the star was measured…
Probing magnetic fields in high-redshift galactic systems is crucial to investigate galactic dynamics and evolution. Utilizing the rotation measure of the background quasars, we have developed a radial profile of the magnetic field in a…
We demonstrate that for weak flares the dependence on spottedness can be rather weak. The fact is that such flares can occur both in small and large active regions. At the same time, powerful large flares of classes M and X occur much more…
All transiting planet observations are at risk of contamination from nearby, unresolved stars. Blends dilute the transit signal, causing the planet to appear smaller than it really is, or produce a false positive detection when the target…
By analysing K2 short-cadence observations we detect starspots on WASP-85A, the host star of the hot Jupiter WASP-85Ab. The detection of recurring starspot occultation events indicates that the planet's orbit is aligned with the star's…
High resolution imaging is an important tool for follow-up study of exoplanet candidates found via transit detection with the Kepler Mission. We discuss here HST imaging with the WFC3 of 23 stars that host particularly interesting Kepler…
The rotational profile of the Sun is considered to be one of the key inputs in a solar dynamo model. Hence, precise and long-term measurements of this quantity is important for our understanding of solar magnetism and its variability. In…
The evolution of starspots of the giant primaries of RS CVn systems is typically detected indirectly with photometric and spectroscopic monitoring. These observations suggest slowly-evolving stellar surfaces and can constrain differential…
The spin-orbit angle between a stellar spin axis and its planetary orbital axis is a key diagnostic of planetary migration pathways, yet the mechanisms shaping the observed spin-orbit distribution remain incompletely understood. Combining…