Related papers: AY Peg, a large amplitude Algol-type star

TESS photometry is analyzed for 432 classical Be stars observed in the first year of the mission. The often complex and diverse variability of each object in this sample is classified to obtain an understanding of the behavior of this class…

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…

The Fourier decomposition was applied to the light curves of the short period variable stars discovered by the OGLE team in Omega Cen. The phi_21 parameters are confined in a narrow strip for periods between 0.042 d and 0.07 d. Toward…

New eclipse timings of the Z Cam-type dwarf nova AY Psc were measured and the orbital ephemeris was revised. Based on the long-term AAVSO data, moreover, the outburst behaviors were also explored. Our analysis suggests that the normal…

We predict mean angular diameters and amplitudes of angular diameter variations for all monoperiodic Pop.I Cepheids brighter than <V> = 8.0mag. The catalog is intended to aid selecting most promising Cepheid targets for future…

Expected mean angular diameters and amplitudes of angular diameter variations are estimated for all monoperiodic Classical Cepheids brighter than <V> = 8.0mag. The catalog is intended to help selecting best Cepheid targets for…

Phenomenological characteristics of the sample of the Algol-type stars are revised using a recently developed NAV ("New Algol Variable") algorithm (2012Ap.....55..536A, 2012arXiv 1212.6707A) and compared to that obtained using common…

The upper main sequence magnetic chemically peculiar (Ap) stars exhibit a non-uniform distribution of chemical elements across their surfaces and with height in their atmospheres. These inhomogeneities, responsible for the conspicuous…

As part of a project to better characterize comparatively bright, yet little studied cataclysmic variables time resolved photometry of the three eclipsing novalike variables EC 21178-5417, GS Pav und V345 Pav is presented. Previously known…

We present the results of a spectroscopic follow-up of various puzzling variable objects detected in the OGLE-III Galactic disk and bulge fields. The sample includes mainly short-period multi-mode pulsating stars that could not have been…

We present near-infrared, H-band (1.45-1.85 microns) observations of the eclipsing dwarf nova, IP Peg, in quiescence. The light curves are composed of ellipsoidal variations from the late-type secondary star and emission from the accretion…

The pulsating white dwarf star PY Vul (G~185-32) exhibits pulsation modes with peculiar properties that set it apart from other variable stars in the ZZ Ceti (DAV) class. These peculiarities include a low total pulsation amplitude, a mode…

We present an analysis of the apsidal motion and light curve parameters of 54 never-before-studied galactic Algol-type binaries. This is the first analysis of such a large sample of eccentric eclipsing binaries in our Galaxy, and has…

Algol ($\beta$ Persei) is the prototypical semi-detached eclipsing binary and a hierarchical triple system. From 2006 to 2010 we obtained 121 high-resolution and high-S/N \'{e}chelle spectra of this object. Spectral disentangling yields the…

WY Per and RW Leo are two Algol-type binaries. Based on our new CCD observations and the almost century-long historical record of the times of primary eclipse for WY Per and RW Leo, the orbital period changes and their explanations were…

Following the discovery of a new class of X-ray variability seen in four galaxies, dubbed Quasi-Periodic Eruptions (QPEs), we reconsider the variability seen in the low-mass AGN 2XMM J123103.2+110648 to ascertain whether it should be…

We report new and archival K-band interferometric uniform disk diameters obtained with the Palomar Testbed Interferometer for the eclipsing binary star $\epsilon$ Aurigae, in advance of the start of its eclipse in 2009. The observations…

We present a detailed lightcurve analysis for a sample of bright semiregular variables based on long-term (70--90 years) visual magnitude estimates carried out by amateur astronomers. Fundamental changes of the physical state (amplitude…

The detailed chemical composition of the atmosphere AY Cet (HD 7672) is determined from a high-resolution spectrum in the optical region. The main atmospheric parameters and the abundances of 22 chemical elements, including key species such…

We report on finding variations in amplitude of the two main oscillation frequencies found in the Be star Achernar, over a period of 5 years. They were uncovered by analysing photometric data of the star from the SMEI instrument. The two…