The transfer of matter between a circumbinary disk and a young binary system remains poorly understood, obscuring the interpretation of accretion indicators. To explore the behavior of these indicators in multiple systems, we have performed the first systematic time-domain study of young binaries in the ultraviolet. We obtained far- and near-ultraviolet HST/COS spectra of the young spectroscopic binaries DQ Tau and UZ Tau E. Here we focus on the continuum from 2800 to 3200{AA} and on the CIV doublet ({lambda}{lambda}1548.19,1550.77{AA}) as accretion diagnostics. Each system was observed over three or four consecutive binary orbits, at phases ~0, 0.2, 0.5, and 0.7. Those observations are complemented by ground-based U-band measurements. Contrary to model predictions, we do not detect any clear correlation between accretion luminosity and phase. Further, we do not detect any correlation between CIV flux and phase. For both stars the appearance of the CIV line is similar to that of single Classical T Tauri Stars (CTTSs), despite the lack of stable long-lived circumstellar disks. However, unlike the case in single CTTSs, the narrow and broad components of the CIV lines are uncorrelated, and we argue that the narrow component is powered by processes other than accretion, such as flares in the stellar magnetospheres and/or enhanced activity in the upper atmosphere. We find that both stars contribute equally to the narrow component CIV flux in DQ Tau, but the primary dominates the narrow component CIV emission in UZ Tau E. The CIV broad component flux is correlated with other accretion indicators, suggesting an accretion origin. However, the line is blueshifted, which is inconsistent with its origin in an infall flow close to the star. It is possible that the complicated geometry of the region, as well as turbulence in the shock region, are responsible for the blueshifted line profiles.
The data files includes photometric observations of the eclipsing binary system IU Aurigae. New photometric observations were made on 13 nights at the Ankara University Observatory (AUO) in 1997/1998 by using a 30cm Cassegrain-Maksutov telescope. The detector was a single-channel, uncooled SSP-5 photometer equipped with Hamamatsu R1414 photomultiplier tube. Observational standard errors determined from check star (HD 35633 = SAO 58053) measurements are 0.014mag, 0.012mag, and 0.018mag in U, B, and V filters, respectively. A total of 966, 959, 947 original data and of 118, 117, 117 reduced (averaged) data points is included for each UBV filters, respectively.
Long-term photometric and spectroscopic observations of the yellow symbiotic star LT Del are analyzed. UBV light curves are presented. Based on the observations of 20 cycles, we have refined the orbital period of the star, P=476.0d+/-1.0d. The brightness has been found to be unstable at some orbital phases with an amplitude up to 0.3m.
New and complete UBV light curves and times of minimum are presented for the Algol type eclipsing binary V477 Cygni (Sp. A3V+F5V, m_v_=8.5, P=2.347days). The binary orbit of the system is highly eccentric and the system shows an apsidal motion. Using the Wilson-Devinney method, two photometric models, without (MODEL A) and with (MODEL B) third-body light contribution to the total light of the system, are obtained. Period analysis also gives some slender evidence for the unseen third-body in the system with the orbital period of about 157 years. In the MODEL A approximation the apsidal motion period is obtained to be 371 years while it is about 434 years in the MODEL B approximation. The photometric mass ratio (q=0.75) is in good agreement with the spectroscopic value given by Popper (1968ApJ...154..191P). The masses we obtained are 1.80+/-0.10 solar masses and 1.35+/-0.08 solar masses and the radii are 1.60+/-0.03 solar radii and 1.42+/-0.03 solar radii for the primary and secondary components, respectively. Absolute dimensions have been compared with the models using a moderate amount of convective overshooting and mass loss given by Claret & Gimenez (1991A&AS...87..507C). In the logM-logR diagram both components are located above but close to the ZAMS. It is possible to say from the logTe-logL diagram that the secondary component is just coming to the main sequence while the primary is slightly evolved from the ZAMS. The theoretical evolutionary models give an age of 6.4x10^8^yrs for the system.
New photometry obtained in 2000-2008 is presented for the post-AGB star IRAS 22272+5435 = V354 Lac. The star showed semi-regular light variations with varying amplitudes.
We present the results of the photometric CCD search for B-type pulsators in the central region of Chi Persei (NGC 884) open cluster. In addition to the two newly-discovered Beta Cephei stars we found 11 other variables in the observed field. The photometric data for them are given in the file 'bmag' and 'vmag' for B and V-filter data, respectively. In addition, we present the new UBV magnitudes for stars in the observed field. This is Table 4 of the paper, available only in electronic form.
The near-contact system RU UMi with an F0 primary and a K5 secondary was observed in U, B and V wavelengths in May and July 1998, as well as in March, May and July 1999. Six new observed times of minima are given and a new ephemeris is proposed. The basic parameters of the system extracted by our observations were used for spot modelling of the light curves. A simple spot distribution was determined, based on a model with one relatively small cool spot on the surface of the secondary. Absolute elements were calculated and the evolutionary status was determined. Our data favor a semi-detached configuration, with the secondary filling its inner Roche lobe; the primary must also be near the limits of its lobe.
The BV photometric investigation of the Southern globular cluster NGC 1904 was carried out using the 1m telescope of Cerro Las Campanas (CARSO, 2 nights in February 1973 and 2 nights in April 1973), and the 1m telescope at la Silla (ESO, 4 nights in February 1975). The identification of the stars was made by B. Skiff (Lowell Obs.) in October 2010.
The photoelectric and photographic observations of the supergiant HD 179821 with a large infrared excess, a candidate for protoplanetary objects during 1899-1999 are presented.
