相关论文: A photometric long-term study of CP stars in open …

Recent re-determination of stellar atmospheric parameters for a sample of stars observed during the {\it Kepler} mission allowed to enlarge the number of {\it Kepler} B-type stars. We present the detailed frequency analysis for all these…

We study the different patterns of interannual magnetic variability in stars on or near the lower main sequence, approximately solar-type (G-K dwarf) stars in time series of 36 years from the Mount Wilson Observatory Ca\,{\sc ii}\,H\&K…

We utilize Kepler data to study the precision differential photometric variability of solar-type and cooler stars at different timescales, ranging from half an hour to 3 months. We define a diagnostic that characterizes the median…

We have been using the Keck I High Resolution Spectrograph (HIRES) to search for planetary companions in the Hyades cluster. We selected four stars from this sample which showed significant radial velocity variability on short timescales to…

The study of stellar activity is important because it can provide new constraints for dynamo models, when combined with surface rotation rates and the depth of the convection zone. We know that the dynamo mechanism, which is believed to be…

Chemically peculiar (CP) stars of the upper main sequence are characterised by specific anomalies in the photospheric abundances of some chemical elements. The group of CP2 stars, which encompasses classical Ap and Bp stars, exhibits…

We used the Ultraviolet and Visual Echelle Spectrograph of the ESO-Very Large Telescope to obtain a high resolution and high signal-to-noise ratio spectrum of Stock 16-12, an early-type star which previous Delta-a photometric observations…

Our knowledge of stellar evolution and of the structure and chemical evolution of the Galactic disk largely builds on the study of open star clusters. Because of their crucial role in these relevant topics, large homogeneous catalogues of…

We report the results of a time-series CCD photometric survey of variable stars in the field of the open cluster NGC 2126. In about one square degree field covering the cluster, a total number of 21 variable candidates are detected during…

Rotation is a critical physical process operating in the formation of Am stars. There is a strong correlation between low-velocity rotation and chemical peculiarity. However, the existence of many non-CP slow rotators challenges the…

The Delta a photometric system provides an efficient observational method to identify and distinguish magnetic and several other types of chemically peculiar (CP) stars of spectral types B to F from other classes of stars in the same range…

Stellar activity cycles are known to be a widespread phenomenon amongst moderately active solar- and late-type stars from long-term periodic variations in chromospheric Ca II H and K emission lines, yet to date only a handful of coronal…

The paper presents the first results of the ongoing spectropolarimetric monitoring of magnetic fields of stars, whose chemically peculiar nature has been previously revealed with the 1-m SAO RAS telescope. We selected the sample candidates…

We present the results of a high-cadence photometric survey of an $11'\times11'$ field centred on the globular cluster M71, with the Near-Infrared Transiting ExoplanetS Telescope. The aim of our survey is to search for stellar variability…

Approximately four thousand light curves of red variable stars in the LMC were selected from the 2.3-years duration MOA database by a period analysis using the Phase Dispersion Minimization method. Their optical features (amplitudes,…

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 beta Cephei stars and slowly pulsating B (SPB) stars are massive main sequence variables. The strength of their pulsational driving strongly depends on the opacity of iron-group elements. As many of those stars naturally occur in young…

We present VI-band photometry for stars in the metal-rich globular cluster NGC 6496. Our time-series data were cadenced to search for long period variables (LPVs) over a span of nearly two years, and our variability search yielded the…

The cyclicity of 33 solar-type stars that are similar to 11-year and to the quasi-biennial variations of solar radiation have studied. Our calculation were based on new simultaneous observations of the flux variations of the photospheric…

A photometric variability study of a sample of northern field stars, which previously classified as either PMS or Herbig Ae/Be objects, has been undertaken with the purpose of detecting {\delta} Scuti-type pulsations. Determination of…