Related papers: The Peculiar Periodic YSO WL 4 in Rho Ophiuchus

Orbital period and multi-color light curves' investigation of OW Leo are presented for the first time. The orbital period of OW Leo is corrected from $P = 0.325545$ days to $P = 0.32554052$ days in our work, and the observational data from…

TW Coronae Borealis (TW CrB) is a binary system likely to be active showing evidence of starspots and a hotspot. We calculated a new ephemeris based on all available timings from 1946 and find the period to be 0.58887492(2) days. We have…

We report the discovery of a white dwarf exhibiting deep, irregularly shaped transits, indicative of circumstellar planetary debris. Using Zwicky Transient Facility DR2 photometry of ZTF$\,$J013906.17+524536.89 and follow-up observations…

In the second part of the OGLE-III Catalog of Variable Stars (OIII-CVS) we present 197 type II Cepheids and 83 anomalous Cepheids in the Large Magellanic Cloud (LMC). The sample of type II Cepheids consists of 64 BL Her stars, 96 W Vir…

The results of an observation campaign of V0784 Ophiuchi over a time span of two years have revealed a multi-periodic Blazhko effect. A Blazhko effect for V0784 Ophiuchi has not been reported previously. From the observed light curves, 60…

Although triple systems are common, their orbital dynamics and stellar evolution remain poorly understood. We investigated the V1371 Tau system using TESS photometry, multi-epoch spectroscopy, and recent interferometric data, confirming it…

Weak-emission-line QSOs (WLQs) are an enigmatic subclass of the QSO population, as their optical/UV spectra are marked by abnormally weak (or absent) emission lines. To obtain much-needed additional clues to the origin of this and other…

ISO-Oph-50 is a young low-mass object in the ~Myr old Ophiuchus star forming region undergoing dramatic changes in its optical/near/mid-infrared brightness by 2-4 mag. We present new multi-band photometry and near-infrared spectra, combined…

We present a Spitzer IRS study of variability in 14 T Tauri stars in the Taurus and Chamaeleon star-forming regions. The sample is composed of transitional and pre-transitional objects which contain holes and gaps in their disks. We detect…

Radial-velocity measurements and sine-curve fits to the orbital radial velocity variations are presented for ten close binary systems: OO Aql, CC Com, V345 Gem, XY Leo, AM Leo, V1010 Oph, V2612 Oph, XX Sex, W UMa, and XY UMa. Most of these…

We present the first time resolved medium resolution optical spectroscopy of the recently identified peculiar Intermediate Polar (IP) 1RXSJ154814.5-452845, which allows us to precisely determine the binary orbital period…

We report on 2MASS J01542930+0053266, a faint eclipsing system composed of two M dwarfs. The variability of this system was originally discovered during a pilot study of the 2MASS Calibration Point Source Working Database. Additional…

LAMOST J052016.79+345651.7 was identified as an EW-type eclipsing binary by Chen et al. when studying the periodic variable stars based on the ZTF telescope. An orbital period of 0.3507818 days has been reported. Using the ZTF g, r, i band…

We have performed a structure function analysis of the Rossi X-ray Timing Explorer All Sky Monitor data to search for variability in 24 blazars using data trains that each exceed 12 years. Although 20 of them show nominal periods though…

We present results from several years of fast optical photometry of 4U0614+091 (V1055 Orionis), a candidate ultracompact X-ray binary most likely consisting of a neutron star and a degenerate secondary. We find evidence for strong…

We report new multi-colour photometry and high-resolution spectroscopic observations of the long-period variable V501 Aur, previously considered to be a weak-lined T-Tauri star belonging to the Taurus-Auriga star-forming region. The…

We determine the orbital elements for the K0 IV + white dwarf (WD) system IP Eri, which appears to have a surprisingly long period of 1071 d and a significant eccentricity of 0.25. Previous spectroscopic analyses of the WD, based on a…

We report the results of the first long-term (1990-2014) optical spectro-photometric monitoring of a binary black hole candidate QSO E1821+643, a low-redshift high-luminosity radio-quiet quasar. In the monitored period the continua and…

R144 is a WN6h star in the 30 Doradus region. It is suspected to be a binary because of its high luminosity and its strong X-ray flux, but no periodicity could be established so far. Here, we present new Xshooter multi-epoch spectroscopy of…

The ~2 Myr old classical T Tauri star CI Tau shows periodic variability in its radial velocity (RV) variations measured at infrared (IR) and optical wavelengths. We find that these observations are consistent with a massive planet in a…