Related papers: Estimating stellar rotation from starspot detectio…
CoRoT-2, the second planet-hosting star discovered by the CoRoT satellite, is a young and active star. A total of 77 transits were observed for this system over a period of 135 days. Small modulations detected in the optical light curve of…
We present photometry of HD 189733 during eight transits of its close-in giant planet, and out-of-transit photometry spanning two years. Using the transit photometry, we determine the stellar and planetary radii and the photometric…
The recent discovery of a planetary transit in the star HD 209458, and the subsequent highly precise observation of the transit lightcurve with Hubble Space Telescope, is encouraging to search for any phenomena that might induce small…
Planetary transits provide a unique opportunity to investigate the surface distributions of star spots. Our aim is to determine if, with continuous observation (such as the data that will be provided by the Kepler mission), we can in…
A number of planet-host stars have been observed to rotate with a period equal to an integer multiple of the orbital period of their close planet. We expand this list by analyzing Kepler data of HAT-P-11 and finding a period ratio of 6:1.…
When a planet passes in front of a starspot during a transit of its host star, it causes a small upward blip in the light curve. Modelling the transit with the starspot allows the size, brightness and position of the spot to be measured. If…
We present synoptic optical photometry of HD 189733, the chromospherically active parent star of one of the most intensively studied exoplanets. We have significantly extended the timespan of our previously reported observations and refined…
The stellar rotation periods of ten exoplanet host stars have been determined using newly analysed Ca II H & K flux records from Mount Wilson Observatory and Stromgren b, y photometric measurements from Tennessee State University's…
We report the first detection of a planetary transit by spectroscopic measurements. We have detected the distortion of the stellar line profiles during a planetary transit. With the ELODIE spectrograph we took a sequence of high precision…
We investigate the effect of planetary rotation on the transit spectrum of an extrasolar giant planet. During ingress and egress, absorption features arising from the planet's atmosphere are Doppler shifted by of order the planet's…
Observations of nine transits of WASP-107 during the {\it K2} mission reveal three separate occasions when the planet crossed in front of a starspot. The data confirm the stellar rotation period to be 17 days --- approximately three times…
We investigate whether rings around extrasolar planets could be detected from those planets' transit lightcurves. To this end we develop a basic theoretical framework for calculating and interpreting the lightcurves of ringed planet…
Stellar activity features such as spots can create complications in determining planetary parameters through spectroscopic and photometric observations. The overlap of a transiting planet and a stellar spot, for instance, can produce…
There have been numerous reports of anomalies during transits of the planet TrES-1b. Recently, Rabus and coworkers' analysis of HST observations lead them to claim brightening anomalies during transit might be caused by either a second…
Understanding the distribution of angular momentum during the formation of planetary systems is a key topic in astrophysics. Data from the $\textit{Kepler}$ and $\textit{Gaia}$ missions allow to investigate whether stellar rotation is…
The Hubble Space Telescope (HST) and the Kepler space mission observed a large number of planetary transits showing anomalies due to starspot eclipses, with more such observations expected in the near future by the K2 mission and the…
The differential rotation of the Sun is a crucial ingredient of the dynamo theory responsible for the generation of its magnetic field. Currently, the rotation profile of a star that hosts one or more transiting planets can be estimated. By…
Thanks to observations performed at the Haute-Provence Observatory, Bouchy et al. recently announced the detection of a 2.2-day orbital period extra-solar planet that transits the disk of its parent star, HD189733. With high level of…
We have developed a new model for analysing light curves of planetary transits when there are starspots on the stellar disc. Because the parameter space contains a profusion of local minima we developed a new optimisation algorithm which…
Stellar rotation periods can be determined by observing brightness variations caused by active magnetic regions transiting visible stellar disk as the star rotates. The successful stellar photometric surveys stemming from the Kepler and…