Related papers: Is Shedir Variable?
We used the Aladin Virtual Obsrvatory tool and High Resolution Imager ROSAT archival data to search for X-ray variability in scale of days in 23 young stars in the sigma Orionis cluster and a background galaxy. Five stars displayed…
\gamma Cas is the prototypical classical Be star and is best known for its variable hard X-ray emission. To elucidate the reasons for this emission, we mounted a multiwavelength campaign in 2010 centered around 4 XMM observations. The…
V909 Cas is a little-studied example of a \b{eta} Cep pulsating variable located in the OB association Cas OB8 in the Perseus spiral arm of the Milky Way. Photometric observations in 2016-7 provided 30 new times of pulsation extrema and…
We report the detection of 15 GHz radio continuum emission associated with the classical Cepheid variable star delta Cephei based on observations with the Karl G. Jansky Very Large Array. Our results constitute the first probable detection…
The potential of the Sloan Digital Sky Survey for wide-field variability studies is illustrated using multi-epoch observations for 3,000,000 point sources observed in 700 deg2 of sky, with time spans ranging from 3 hours to 3 years. These…
Based on data from the ongoing OGLE Galaxy Variability Survey (OGLE GVS) we have verified observed properties of stars detected by the near-infrared VVV survey in a direction near the Galactic plane at longitude l~-27 deg and recently…
The cosmological variability of alpha is probed from individual observations of pairs of FeII lines. This procedure allows a better control of the systematics and avoids the influence of the spectral shifts due to ionization inhomogeneities…
This paper contains the fifth part of the Catalog of Variable Stars created from the V-band photometric data collected by 9x9 deg camera of the All Sky Automated Survey. Preliminary list of variable stars found in the fields located between…
We present 18 years of OGLE photometry together with spectra obtained over 12 years, revealing that the early Oe star AzV 493 shows strong photometric (Delta I < 1.2 mag) and spectroscopic variability with a dominant, 14.6-year pattern and…
We present the first extensive photometric results of CL Aur from our BVRI CCD photometry made on 22 nights from 2003 November through 2005 February. Fifteen new timings of minimum light were obtained. During the past 104 years, the orbital…
The G0V star HD166435 has been observed by the fiber-fed spectrograph ELODIE as one of the targets in the large extra-solar planet survey that we are conducting at the Observatory of Haute-Provence. We detected coherent, low-amplitude,…
We investigate temporally changing variability amplitudes and the multi-periodicity of the type-I Cepheid Polaris using 161 high-precision radial velocity (RV) and bisector inverse span (BIS) measurements based on optical spectra recorded…
A photometric campaign analysis of the star NSVS 7606408 has been conducted in order to determine the type of variability and high accuracy ephemeris. By combining the obtained data with other datasets available, it was tried to improve the…
We present the results of a new search for variable stars in the Local Group dwarf galaxy Leo A, based on deep photometry from the Advanced Camera for Surveys onboard the Hubble Space Telescope. We detected 166 bona fide variables in our…
From the Fourier analysis of the catalogue of ~200,000 variable candidates in the OGLE-II Galactic fields, we found a sample of about 230 short-period low-amplitude variable stars. From their position in the colour-magnitude diagram and the…
The variabile star Delta Scorpii is in conjunction with the Sun at the end of November each year. We studied its magnitude by averaging the observations of 28 Nov - 1 Dec from 1996 to 2013 using the coronograph LASCO C3 on-board the SOHO…
We present the results of a long-term monitoring campaign of the H\alpha line in a sample of bright OB-supergiants (O7.5-B9) that aims at detecting rotationally modulated changes potentially related to the existence of large-scale wind…
We present an analysis of long-term optical monitoring observations and optical spectroscopic observations of the counterpart to CXOU J205847.5+414637 (high mass X-ray binary system). We search for a variability in the light curve of Be…
An analysis is made of the spectral line shapes of tau Bootis using high resolution (0.026 A) and high signal-to-noise (S/N~400) data in an effort to confirm the planet hypothesis for this star. Changes in the line shape are quantified…
Stellar photometric variability offers a novel probe of the interior structure and evolutionary state of stars. Here we present a census of stellar variability on day to decade timescales across the color-magnitude diagram for 73,000 stars…