Related papers: Variability Type Determination and High Precision …
In the first spectroscopic campaign for a PG 1716 variable (or long-period pulsating subdwarf B star), we succeeded in detecting velocity variations due to g-mode pulsations at a level of 1.0-1.5 km/s.The observations were obtained during…
Spectra of four non-magnetic chemically peculiar late B type stars (HgMn) stars are analysed to detect periodic spectral line variations (LPVs). A procedure developed to study LPVs in Slowly Pulsating B stars has been adopted as pulsational…
The advent of space-based photometry provides the opportunity for the first precise characterizations of variability in Mercury-Manganese (HgMn/CP3) stars, which might advance our understanding of their internal structure. We have carried…
Aims: We present accurate photometric time series of two Be stars: NW Ser and V1446 Aql. Both stars were observed at the Observatorio de Sierra Nevada (Granada) in July 2003 with an automatic four-channel Str\"omgren photometer. We also…
The ESA HIPPARCOS satellite has provided astrometry of unprecedented accuracy, allowing to reassess, improve and refine the pre-HIPPARCOS luminosity calibrations. We review the "classical" absolute magnitude calibrations with the…
We analysed V-filter ASAS-3 photometry of 41 known Beta Cephei-type stars. The ASAS-3 photometry was combined with the archival data, if available, to determine long-term stability of periods and amplitudes of excited modes. We detected…
We have conducted a photometric survey of the globular cluster NGC 6397 in a search for variable stars. We obtained ~11h of time-resolved photometric images with one ne European Southern Observatory-Very Large Telescope using the FOcal…
We present a comprehensive re-analysis of stellar photometric variability in the field of the open cluster M37 following the application of a new photometry and de-trending method to MMT/Megacam image archive. This new analysis allows a…
We present a novel automated methodology to detect and classify periodic variable stars in a large database of photometric time series. The methods are based on multivariate Bayesian statistics and use a multi-stage approach. We applied our…
Preliminary results on the discovery and follow-up observations of a new $\delta$ Scuti pulsator in the Cygnus field are presented. The variability of the star HD 207331 was detected while testing a Str\"omgren spectrophotometer attached to…
The unprecedented precision of broadband stellar photometry achieved with the planet-hunting missions CoRoT and \textit{Kepler} initiated a new era in examining the magnetically-driven brightness variations of hundreds of thousands of…
This study aims to investigate the systematics in planetary ephemeris reference frames through pulsar timing observations. We used the published data sets from several pulsar timing arrays and performed timing analyses for each pulsar using…
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 present the analysis of the variability of HD 170699, a COROT star showing the characteristics of a non evolutionary Delta Scuti star with high rotational velocity. There is a clear period of 10.45 c/d with 5.29 mmag amplitude in the y…
About 10% of upper main sequence stars are characterised by the presence of chemical peculiarities, often found together with a structured magnetic field. The atmospheres of most of those chemically peculiar stars present surface spots,…
We present the results of recent long-term BVRcIc photometric monitoring of the type II Cepheid prototype W Virginis. These new observations, made during the 2006 and 2007 observing season, represent the longest homogeneous, multicolor…
We report our investigation of 1SWASP J234401.81-212229.1, a variable with a 18461.6 s period. After identification in a 2011 search of the SuperWASP archive for main-sequence eclipsing binary candidates near the distribution's short-period…
Transiting planet discoveries have yielded a plethora of information towards understanding the structure and atmospheres of extra-solar planets. These discoveries have been restricted to the short-period or low-periastron distance regimes…
We present 31 bright eclipsing contact and semi-detached binaries that showed high period change rates in a 5 year interval in observations by the All-Sky Automated Survey (ASAS). The time-scales of these changes range from only 50 up to…
The results of long-term spectral observations were used to search for changes in planetary nebulae and emission-line stars. Significant increase of excitation degree is found in two objects: M1-6 and M1-11.