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.
We present new results of our UBV photometry for HD 179821=V1427 Aql, an F supergiant with an infrared excess, from 2000 to 2008. The semiregular low-amplitude ({Delta}=0.05-0.20mag) photometric variability of the star with a cycle period from 130 to 200 days is caused by pulsations, along with the instability of a variable stellar wind. V1427 Aql also exhibits a long-term trend in the brightness and colors that is probably attributable to a change in the stellar temperature as a result of mass loss episodes, which cause variations in the continuum formation level. We present the results of our JHKLM photometry for V1427 Aql in 1992-2008.
We present UBV photoelectric observations of the W UMa star BF Pav obtained between 1987 and 1993. A time-of-minimum study allows detection of a likely period increase of about 0.015s/yr. The Wilson-Devinney code is employed to simultaneously model the B and V light curves for several fixed values of the mass ratio q. From the quality-of-fit of the different solutions an approximate value of q=1.4+/-0.2 is derived. Absolute values of masses, dimensions, and luminosities are estimated by means of standard mass-luminosity relations for main-sequence stars. The detected period variation determines a lower limit of 5x10^-7M_{sun}_/yr for the rate of mass transfer from the less-massive to the more-massive component. We speculate that BF Pav has recently become in contact and is now in a rapid phase of mass transfer.
We present our long-term photometric and spectroscopic observations of a high-latitude B supergiant with an infrared excess - the protoplanetary nebula IRAS 18062+2410. Our UBV observations in 2000-2006 have confirmed the rapid irregular photometric variability of the star with a maximum amplitude as high as 0.4m in V that we found previously. The B-V and U-B color indices vary with amplitudes as high as 0.10m and 0.25m, respectively, and show no clear correlation with the brightness. Our V-band CCD observations on 11 nights in 2006 have revealed brightness trends during the night. The variability of IRAS 18062+2410 is similar in pattern to the light variations in other hot post-AGB objects and some of the nuclei of young planetary nebulae. We assume that pulsations and a variable stellar wind can be responsible for the variability of these stars. In addition to the rapid variability, our 12-year-long observations have revealed a systematic decline in the mean brightness of IRAS 18062+2410.
The catalogue collects all UBV photoelectric photometry data published since 1953 to the end of 1985 in the Johnson and Morgan system. In addition, data obtained in closely related systems using UBV filters have also been collected. All the data have been merged, yielding a final catalogue of 136719(*) entries concerning 87267 stars and components. The data have been taken from 1413 (UBV) and 127 (other) references found in 73 different periodicals. Great care has been taken to detect and correct all kinds of errors. (*) Two entries have been deleted in version 'B' of this catalogue The analysis of the data is published in 1987A&AS...71..119M
The previous compilation of UBV data (Mermilliod 1986a,b,c) contains the UBV photoelectric observations published between 1953 and 1986. The present supplement adds the data published between 1986 and the end of 1992 which represent 25639 new UBV data. The corresponding references were numbered in continuation of the main catalogue and go from number 1603 to 1784. See <http://obswww.unige.ch/gcpd/ph01.html> for a description of the UBV photoemtric system.
The catalog contains approximatively 10,000 photoelectric observations of Cepheid variable stars, observed by the authors or derived from published data. The catalog contains data on more than 300 stars; of these approximately 230 can be classified as "well-observed".
