Related papers: Apparent non-variable stars from the Kepler missio…
Astronomical data are typically irregular in time, e.g. the space (HIPPARCOS/TYCHO, KEPLER, GAIA, WISE etc.) and ground-based CCD (NSVS, ASAS, CRTS, SuperWASP etc.) and photographic (Harvard, Sonneberg, Odessa etc.) photometrical surveys.…
We report on a population of short duration near-ultraviolet (NUV) flares in stars observed by the Kepler and GALEX missions. We analyzed NUV light curves of 34,276 stars observed from 2009-2013 by both the GALEX (NUV) and Kepler (optical)…
The 60 known rapidly oscillating Ap (roAp) stars are excellent laboratories to test pulsation models in the presence of stellar magnetic fields. Our survey is dedicated to search for new group members in the Northern Hemisphere. We attempt…
Aims: We aim to measure the starspot rotation periods of active stars in the Kepler field as a function of spectral type and to extend reliable rotation measurements from F-, G-, and K-type to M-type stars. Methods: Using the Lomb-Scargle…
The high quality light curves of Kepler space telescope make it possible to analyze the optical variability of AGNs with an unprecedented time resolution. Studying the asymmetry in variations could give independent constraints on the…
Stars exhibit a bewildering variety of variable behaviors ranging from explosive magnetic flares to stochastically changing accretion to periodic pulsations or rotations. The principal LSST surveys will have cadences too sparse and…
High precision Kepler photometry is used to explore the details of AGB light curves. Since AGB variability has a typical time scale on order of a year we discuss at length the removal of long term trends and quarterly changes in Kepler…
The 4-year light curves of 156,717 stars observed with NASA's Kepler mission are analyzed using the AutoRegressive Planet Search (ARPS) methodology described by Caceres et al. (2019). The three stages of processing are: maximum likelihood…
We measure rotation periods for 12151 stars in the Kepler field, based on the photometric variability caused by stellar activity. Our analysis returns stable rotation periods over at least six out of eight quarters of Kepler data. This…
The unprecedented light curves of the Kepler space telescope document how the brightness of some stars pulsates at primary and secondary frequencies whose ratios are near the golden mean, the most irrational number. A nonlinear dynamical…
We report on candidate active galactic nuclei (AGN) discovered during the monitoring of $\sim$500 bright (r < 18 mag) galaxies over several years with the Kepler Mission. Most of the targets were sampled every 30 minutes nearly continuously…
Asteroseismology has proven to be an excellent tool to determine not only the global stellar properties with a good precision but also to infer stellar structure, dynamics, and evolution for a large sample of Kepler stars. Prior to the…
A photometric study of variable stars in the field of old open cluster NGC 188 is discussed. Observations were carried out in two bands R and I for 5513 stars up to R = 17 mag in the field of 1.5 x 1.5 grad. around the cluster. The…
Optical polarimeters are typically calibrated using measurements of stars with known and stable polarization parameters. However, there is a lack of such stars available across the sky. Many of the currently available standards are not…
The NASA Kepler mission has observed more than 190,000 stars in the constellations of Cygnus and Lyra. Around 4 years of almost continuous ultra high-precision photometry have been obtained reaching a duty cycle higher than 90% for many of…
In this paper, we study stellar light curves from the TESS satellite (Transiting Exoplanet Survey Satellite) for the presence of stellar flares. The main aim is to detect stellar flares using two-minutes cadence data and to perform…
Before the launch of the Kepler Space Telescope, most studies of the rapidly oscillating Ap (roAp) stars were conducted with ground-based photometric $B$ observations, supplemented with high-resolution time-resolved spectroscopy and some…
We have conducted a deep photometric survey of a 0.5 deg x 0.5 deg area of the Galactic Plane using the WFI instrument on the 2.2-m ESO telescope on La Silla, Chile. The dataset comprises a total of 267 R-band images, 204 from a 16 day…
The ~ 200,000 stars observed by the Kepler mission have provided unprecedented constraints across astrophysics. With the advent of modern spectroscopic and photometric surveys, new limits in stellar characterizations are within reach. In…
The optical, full-phase photometric variations of a short-period planet provide a unique view of the planet's atmospheric composition and dynamics. The number of planets with optical phase curve detections, however, is currently too small…