Related papers: Lambda Bootis stars in the SuperWASP survey
Recent monitoring programs of ultra cool field M and L dwarfs (low mass stars or brown dwarfs) have uncovered low amplitude photometric I-band variations which may be associated with an inhomogeneous distribution of photospheric…
Massive early-type stars vary; low-mass late-type brown dwarfs vary, too. I will make a short, but illustrative, summary of my previous studies on stellar and sub-stellar photometric variability (including the discovery of the most variable…
The All Sky Automated Survey (ASAS) data, covering nearly 70% of the whole sky south of declination +28 deg, were recently used to discover about 300 Beta Cephei stars brighter than V~11.5 mag. As this means a nearly fourfold increase in…
In recent years, approximately 150 low-mass white dwarfs (WDs), typically with masses below 0.4 solar masses, have been discovered. Observational evidence indicates that most of these low-mass WDs are found in binary systems, supporting…
Unevolved metal poor stars are the witness of the early evolution of the Galaxy. The determination of their detailed chemical composition is an important tool to understand the chemical history of our Galaxy. The study of their chemical…
Stars exhibit a bewildering variety of rapidly variable behaviors ranging from explosive magnetic flares to stochastically changing accretion to periodic pulsations or rotation. The principal Rubin Observatory Legacy Survey of Space and…
The "super-puffs" are a population of planets that have masses comparable to that of Neptune but radii similar to Jupiter, leading to extremely low bulk densities ($\rho_p \lesssim 0.2\,\mathrm{g}\,\mathrm{cm}^{-3}$) that are not easily…
We report on the results of an I-band photometric variability survey of eighteen L dwarfs. We find that seven exhibit statistically significant variations above the 95.4% confidence level with root-mean-square scatter (including photometric…
We present high-resolution Magellan/MIKE spectra of the four brightest confirmed red giant stars in the ultra-faint dwarf galaxy Bootes II (Boo II). These stars all inhabit the metal-poor tail of the Boo II metallicity distribution…
We present a comprehensive seismic study of the three pulsating stars of $\beta$ Cep/SPB type: $\nu$ Eridani, 12 Lacertae and $\gamma$ Pegasi. Models with the modified mean opacity profile are constructed in order to account for both the…
We search a sample of 9,361,613 isolated sources with 13<g<14.5 mag for slowly varying sources. We select sources with brightness changes larger than ~ 0.03 mag/year over 10 years, removing false positives due to, for example, nearby bright…
This paper is the first part of the Catalog of Periodic Variable Stars in the Galactic bulge. The Catalog is based on observations collected during the OGLE microlensing search. 213 periodic variable stars brighter than I=18 mag: 31…
We examine 4-yr almost continuous Kepler photometry of 115 B stars. We find that the light curves of 39 percent of these stars are simply described by a low-frequency sinusoid and its harmonic, usually with variable amplitudes, which we…
We present a quantitative and homogeneous analysis of the broadband multicolor photometric data sets gathered so far on rapidly pulsating hot B subdwarf stars. This concerns seven distinct data sets related to six different stars. Our…
The physics of magnetic hot stars and how a large-scale magnetic field affects their interior properties is largely unknown. Few studies have combined high-quality observations and modelling of magnetic pulsating stars, known as…
We have carried out a photometric survey of a complete, volume-limited sample of gamma Doradus candidates. The sample was extracted from the Hipparcos catalog and consists of 114 stars with colors and absolute magnitudes within the range of…
The Kepler spacecraft is providing photometric time series with micro-magnitude precision for thousands of variable stars. The continuous time-series of unprecedented time span open up opportunities to study the pulsational variability in…
White dwarfs are well studied objects. The relative simplicity of their physics allows to obtain very detailed models which can be ultimately compared with their observed properties. Among white dwarfs there is a specific class of stars,…
We present homogeneous abundance analysis of over 20 elements for 385 very metal-poor (VMP) stars based on the LAMOST survey and follow-up observations with the Subaru Telescope. It is the largest high-resolution VMP sample (including 363…
We report the discovery by WASP of five planets orbiting moderately bright ($V$ = 11.0-12.9) Solar-type stars. WASP-137b, WASP-143b and WASP-146b are typical hot Jupiters in orbits of 3-4 d and with masses in the range 0.68--1.11 $M_{\rm…