Related papers: Short term period variable stars observed at OAUNI
Oscillation frequencies are the most accurate properties one can measure for a star, potentially allowing detailed tests of stellar models and evolution theories. We briefly review asteroseismology for two classes of stars. In delta Scuti…
Observations from the Heliospheric Imagers (HI-1) on both the STEREO spacecraft have been analysed to search for very long period large amplitude stellar variability, finding 6 new candidates. A total of 85 objects, mostly previously known…
While testing a Stromgren spectrophotometer attached to the 1.5-m telescope at the San Pedro Martir observatory, Mexico, a number of A-type stars were observed, one of which, HD 207331, presented clear indications of photometric…
We carried out observations, with five different instruments ranging in aperture from 0.4m to 10m, of the satellites of Uranus during that planet's 2007 Equinox. Our observations covered specific intervals of time when mutual eclipses and…
Observations for the $\delta$ Scuti star AN Lyn have been made between 2008 and 2016 with the 85-cm telescope at Xinglong station of National Astronomical Observatories of China, the 84-cm telescope at SPM Observatory of Mexico and the…
The results obtained by means of the photometric approach to the study of Delta Sct stars are extensively discussed. The different frequency contents of the three best candidates for asteroseismological studies (FG Vir, 4 CVn and XX Pyx)…
We present new, contemporaneous HST STIS and XMM observations of the O7 III(n)((f)) star xi Per. We supplement the new data with archival IUE spectra, to analyze the variability of the wind lines and X-ray flux of xi Pper. The variable wind…
We present spectroscopy of four cataclysmic variables. Using radial velocity measurements, we find orbital periods for the first time. The stars and their periods are GY Hya, 0.347230(9) d; SDSS J204448-045929, 1.68(1) d; V392 Hya,…
Since 2004, we have been engaged in a long-term observing program to monitor young stellar objects in the Orion Nebula Cluster. We have collected about two thousands frames in V, R, and I broad-band filters on more than two hundred nights…
The first intensive photometric time-series of a Delta Scuti star was obtained from space. Theta2 Tau was monitored with the star camera on the Wide-Field Infrared Explorer (WIRE) satellite. Twelve independent frequencies were detected down…
The searches for transiting exoplanets have produced a vast amount of time-resolved photometric data of many millions of stars. One of the leading ground-based surveys is the SuperWASP project. We present the initial results of a survey of…
We have conducted a 1.5 year-long variability study of the stars in the Cygnus OB2 association, the region in the northern hemisphere with the highest density of optically visible massive stars. The survey was conducted using four pointings…
We present an analysis of observations of the bright star Altair (alpha Aql) obtained using the star camera on the Wide-Field Infrared Explorer (WIRE) satellite. Although Altair lies within the delta Scuti instability strip, previous…
We describe an ongoing variable star search program and present the first reduced results of a search in a 19 square degree (4.4\circle x 4.4\circle) field centered on J2000 {\alpha} = 22:03:24, {\delta} = +18:54:32. The search was carried…
We report on observation and determination of rotational periods of ten weak-line T Tauri stars in the Cepheus-Cassiopeia star-forming region. Observations were carried out with the Cassegrain-Teleskop-Kamera (CTK) at University Observatory…
Long-period variables are bright, evolved red giant stars showing periodic photometric changes due to stellar pulsation. They follow one or more period-luminosity and period-age relations, which make them highly promising distance…
The Gaia DR3 parallax approach was used to estimate the absolute parameters of 2375 Delta Scuti stars from the ASAS catalog. The selected stars have a variety of observational characteristics, with a higher than 80% probability of being…
The photometric properties of the variable stars located in the lower part of the classical instability strip are discussed. The importance of the determination of some light curve parameters and their connection with the stellar models are…
We have explored a sample of suspected A-type binaries in a systematic way, both spectroscopically and photometrically. Due to their location in the H-R diagram, indications of pulsation and/or chemical peculiarities among these suspected…
The first 100 brightest eclipsing systems from the Small Magellanic Cloud were studied for their period changes. The photometric data from the surveys OGLE-II, OGLE-III, OGLE-IV and MACHO were combined with our new CCD observations obtained…