Related papers: LO Peg in 1998: Starspot patterns and differential…
Making use of the data obtained from Kepler satellite, we have analysed an F-type ultra-fast rotator KIC 6791060. We derive a rotational period of 0.34365$\pm$0.00004 d. Multiple periodicity with a period separation of $\sim$0.00016 d was…
Using high-precision photometry from the \textit{Kepler} mission, we investigate patterns of spot activity on the K1-type subgiant component of KIC 11560447, a short-period late-type eclipsing binary. We tested the validity of maximum…
We analyse Kepler light-curves of the exoplanet KOI-13b transiting its moderately rapidly rotating (gravity-darkened) parent star. A physical model, with minimal ad hoc free parameters, reproduces the time-averaged light-curve at the ca. 10…
We report in this paper phase-resolved spectropolarimetric observations of the rapidly-rotating fully-convective M4 dwarf V374 Peg, on which a strong, mainly axisymmetric, large-scale poloidal magnetic field was recently detected. In…
In this study, we considered stellar spots, stellar flares, and also the relation between these two magnetic proccesses that take place on UV Cet stars. In addition, the hypothesis about slow flares described by Gurzadyan (1986 Ap&SS, 125,…
We quantify the effect of starspots for the orbital elements of the spotted RS CVn binary $\lambda$ Andromedae ($\lambda$ And) and present an empirical correction. The aim is to obtain a more precise orbital solution that can be used to…
The coolest dwarf stars are intrinsically faint at visible wavelengths and exhibit rotationally modulated stellar activity from spots and plages. It is advantageous to observe these stars at near infrared (NIR) wavelengths (1-2.5 microns)…
Photometry from Kepler has revealed the presence of cool starspots on the surfaces of thousands of stars, presenting a wide range of spot morphologies and lifetimes. Understanding the lifetime and evolution of starspots across the main…
We explore the connection between starspots and plages of three main-sequence stars by studying the chromospheric and photospheric activity over several rotation periods. We present simultaneous photometry and high-resolution ($R\sim…
We present 23 Doppler images of the spotted RS CVn star HR 1099 from 1981 to 1992. HR 1099 shows a large cool polar spot which has persisted for the 11 years of this study and other low-latitude spots which come and go on relatively short…
Stellar rotation is crucial for studying stellar evolution since it provides information about age, angular momentum transfer, and magnetic fields of stars. In the case of the Sun, due to its proximity, detailed observation of sunspots at…
While stellar rotation periods $P_\mathrm{rot}$ may be measured from broadband photometry, the photometric modulation becomes harder to detect for slower rotators, which could bias measurements of the long-period tail of the…
The study of young Sun-like stars is of fundamental importance to understand the magnetic activity and rotational evolution of the Sun. Space-borne photometry by the Kepler telescope provides unprecedented datasets to investigate these…
We introduce a method of measuring a lower limit to the amplitude of surface differential rotation from high-precision, evenly sampled photometric time series. It is applied to main-sequence late-type stars whose optical flux modulation is…
Accounting for stellar activity is a crucial component of the search for ever-smaller planets orbiting stars of all spectral types. We use Doppler imaging methods to demonstrate that starspot induced radial velocity variability can be…
We present red spectra in the region 7000-8300A of the eclipsing dwarf nova IP Peg, with simultaneous narrow-band photometry centered at 7322A. We show that by placing a second star on the slit we can correct for the telluric absorption…
On the AGB, low to intermediate mass stars blow away their outer envelopes, forming planetary nebulae. Interaction between the planetary nebula and its central progenitor is poorly understood and even more complex when the central object is…
We present an analysis of the starspot evolution, the surface differential rotation (SDR), the correlation between chromospheric activity indicators and the spatial connection between chromospheric and photospheric activities on the active…
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…
We present a detailed analysis of surface inhomogeneities on the K1-type sub-giant component of the rapidly rotating eclipsing binary KIC 11560447, using high-precision Kepler light curves spanning nearly four years, corresponding to about…