The data file (v899her.dat) includes photometric observations of the eclipsing binary system V899 Herculis. The observations were carried out at the Ankara University Observatory in Johnson UBV filters by using an SSP-5 photometer head attached to the 30-cm Maksutov telescope of the Observatory. Observational standard errors are 0.020m, 0.016m, and 0.021m in U, B, and V filters, respectively. A total of 301, 305, and 298 data points are included for each UBV filters, respectively, in the Table.
An analysis of an extensive collection of photometric and spectroscopic observations of the little studied bright Be star V360 Lac lead to the following main conclusions: (1) V360 Lac is a binary system consisting of a B3e primary and a F9IV secondary which probably fills the Roche lobe and losses mass towards the primary. Radial-velocity curves of both components were obtained. (2) The light variations arise from superposition of variations on at least three time scales: phase-locked orbital brightness and colour changes with two minima; sinusoidal variation with a 322.24^d^ period and low-amplitude rapid changes with a possible period of 1.6738^d^. (3) A tentative solution of the B and V light curves which assumes the semi-detached configuration and presence of a disk around the primary, combined with the orbital solution, leads to preliminary basic physical elements of the system which are consistent with the radiative properties of the binary components.
A complete period variation analysis and new light curves of V839 Oph together with new ephemeris data are presented. The period variation was found to be dP/dt=3.1x10^-7d/yr. The period increament indicates that the conservative mass transfer rate from the less massive component to the more massive one is 6.5x10^-7M_sun_/yr. We fitted parabolic and we discuss the possible detection of sinusoidal curves to the (O-C) diagram and sinusoidal oscillations with period of about 20yr and semi-amplitude of 0.0065 day. A simultaneous solution of the B and V light curves was computed using the Wilson-Devinney synthetic light-curve code. The light curve solution indicates that the A-type W UMa-type system is in contact with a filling factor of ~39%.
We present UBV photoelectric and CCD observations of HZ Her/Her X-1 system near its primary minimum in 1999, when the object was in anomalous low X-ray state, together with UBV observations accumulated since 1988.
UBV photometry of 186 stars with 17h < R.A. < 19h listed in Stephenson and Sanduleak's "Luminous Stars in the Southern Milky Way" catalog (Stephenson C.B. & Sanduleak N. 1971, Publ. Warner and Swasey Obs. 1, No. 1) is reported.
Using the Hubble Space Telescope (HST) and the Large Binocular Telescope, we followed the evolution of the Type Ia supernova (SN Ia) 2011fe for an unprecedented 1840 days past B-band maximum light and over a factor of 7 million in flux. At 1840 days, the 4000-17000{AA} quasi-bolometric luminosity is just (420+/-20)L_{sun}_. By measuring the late-time quasi-bolometric light curve, we present the first confident detection of ^57^Co decay in a SN Ia light curve and estimate a mass ratio of log(^57^Co/^56^Co)=-1.59_-0.07_^+0.06^. We do not have a clean detection of ^55^Fe, but find a limit of ^55^Fe/^57^Co<0.22 with 99% confidence. These abundance ratios provide unique constraints on the progenitor system because the central density of the exploding white dwarf(s) dictates these nucleosynthetic yields. The observed ratios strongly prefer the lower central densities of double-degenerate models (^55^Fe/^57^Co=0.27) over the higher central densities of near-Chandrasekhar-mass single-degenerate models (^55^Fe/^57^Co=0.68). However, additional theoretical studies predicting isotopic yields from a broader range of progenitor systems are motivated by these unique observations. We will continue to observe SN 2011fe for another ~600 days with HST and possibly beyond.
Photoelectric (UBVR) observations in 1998-2001 and medium-resolution spectroscopy obtained in the SAO in the same period for the B[e]/X-ray transient CI Cam display cyclic variations with a period of 1100 days.
We present results from a continuing campaign to secure deep multi-colour CCD sequences for photoelectric calibration in UK Schmidt fields with galactic latitudes |b|>50{deg}. In this paper, we present UBVR photometry in 12 fields and BR photometry in a further 14 fields observed within UK Schmidt survey fields centered at {delta}=-30{deg}. Our observations were carried out with the 0.9m Telecope at the Cerro-Tololo Inter-American Observatory.
We present photometry and a preliminary interpretation of a UBVR survey of the Large and Small Magellanic Clouds, which covers 14.5 deg^2^ and 7.2deg^2^, respectively. This study is aimed at obtaining well-calibrated data on the brighter, massive stars, complementing recent, deeper CCD surveys. Our catalog contains 179,655 LMC and 84,995 SMC stars brighter than V~18.0, and is photometrically complete to U~B~V~15.7 and R~15.2, although stars in crowded regions are selectively missed. We compare our photometry to that of others, and describe the need for gravity-dependent corrections to our CCD U-band photometry. We provide a preliminary cross-reference between our catalog stars and the stars with existing spectroscopy.
