Related papers: On the apsidal motion of BP Vulpeculae
We report BVR photometry of the V1343 Aql= SS 433 microquasar at different phases of the 13--day orbital cycle for the 1986--1990 observing seasons. The data include five complete cycles of the 163$^{d}$ precession period of the system. We…
In this paper, the post-1977 photometric observations of PKS 2155-304 are compiled and used to discuss the variation periodicity. Largest amplitude variations ($\Delta U = 1^{m}.5$; $\Delta B = 1^{m}.65$; $\Delta V = 1^{m}.85 $; $\Delta R =…
We present preliminary astrometric results for the closest known brown dwarf binary to the Sun: Epsilon Indi Ba, Bb at a distance of 3.626 pc. Via ongoing monitoring of the relative separation of the two brown dwarfs (spectral types T1 and…
We present a new period study and light-curve solutions for the A-Type W UMa binary GSC 3208 1986. Contrary to a previous claim by R.G. Samec et al. of a rapidly decreasing period, the system's period is increasing moderately on a timescale…
We present phase-resolved spectroscopy and photometry of a source discovered with the Chandra Galactic Bulge Survey (GBS), CXOGBSJ174444.7-260330 (aka CX93 and CX153 in the previously published GBS list). We find two possible values for the…
The first detailed photometric and spectroscopic analysis of the G-type eclipsing binary KM UMa is presented, which indicates that the system is a short-period detached eclipsing binary. The radial velocity curves were calculated using the…
We present time-resolved optical spectroscopy of V458 Vulpeculae (Nova Vul 2007 No. 1) spread over a period of 15 months starting 301 days after its discovery. Our data reveal radial velocity variations in the HeII {\lambda}5412 and HeII…
Since its proposal in 1992, the Applegate mechanism has been discussed as a potential intrinsical mechanism to explain transit timing variations in various kinds of close binary systems. Most analytical arguments presented so far focused on…
The archival spectrum of SDSS J212531.92-010745.9 shows not only the typical signature of a PG1159 star, but also indicates the presence of a companion. With time-series photometry of SDSS J212531.92-010745.9 during 10 nights, spread over…
All data available in B band for the BL Lac object MRK421 from 22 publications are used to construct a historical light curve, dating back to 1900. It is found that the light curve is very complicated and consists of a set of outbursts with…
The millisecond pulsar PSR B1259-63 and the Be star SS2883 are situated in a highly eccentric binary system, with orbital period ~3.4 years. We report on hard X-ray observations obtained with the INTEGRAL satellite close to the 2004…
Period analysis of CCD photometry of V1493 Aql (Nova Aql 1999 no. 1) performed during 12 nights through I and R filters a few weeks after maximum is presented. The PDM method for period analysis (Stellingwerf 1978) is used. The photometric…
We modeled the V-band light curve of beta Lyrae with two stellar components plus an optically thick accretion disc around the gainer assuming a semidetached configuration. We present the results of this calculation, giving physical…
Removing outbursts from multiwavelength light curves of the blazar Mrk~421, we construct outburstless time series for this system. A model-independent power spectrum light curve analysis in the optical, hard X-ray and gamma-rays for this…
In this paper, historical optical(UBVRI) data and newly observed data from the Yunnan Observatory of China(about100 years) are presented for BL Lacertae. Maximum variations in UBVRI: 5.12, 5.31, 4.73, 2.59, and 2.54 and color indices of U-B…
The mean light curve of Betelgeuse is constructed from the visual data in BAA VSS and AAVSO archives. Period analysis reveals clusters of periods around 2000 and 400 days but these are swamped by the long-term trends. No identifiable…
We propose a novel method for determining the ages of low-mass, pre-main sequence stellar systems using the apsidal motion of low-mass detached eclipsing binaries. The apsidal motion of a binary system with an eccentric orbit provides…
New observations are presented of four evolved objects that display long, multi-year variations in their light curves. These are interpreted as good evidence of their binary nature, with the modulation caused by the barycenter motion of the…
We have selected archival observational data for several O and B trapezia in the Milky Way. For each of the main components of the trapezia we obtained transverse velocities from the historical separation data. With this information, and…
Eclipse timing variation analysis has become a powerful method to discover planets around binary systems. We applied this technique to investigate the eclipse times of GK Vir. This system is a post-common envelope binary with an orbital…