Magnitudes in V and B-V and U-B colors observed by the 91-cm telescope at Okayama are presented for 109 stars including both classical and marginal barium stars. The two-color diagram shows a fair amount of spread. This can be interpreted by interstellar reddening and variable amounts of line blocking effect. Both classical and marginal barium stars form a fairly homogeneous group.
A summary of results of the systematic UBV photoelectric monitoring of bright northern Be stars carried out at the Hvar Observatory between 1972 and 1990 is presented. Altogether, 76 Be stars of all luminosity classes were observed and 13848 UBV measurements secured. Simultaneously, 9648 UBV measurements of 48 check stars (most of them of early spectral types) were obtained. A careful transformation of all observations into the standard Johnson system allowed detection and monitoring of even very mild long-term light and colour variations of these objects. Almost all early-type Be stars in the sample turned out to be variable. For several stars phase-locked light variations related to their binary nature were established. Sudden brightenings, on a time scale of a few days, were detected for o Cas and QR Vul.
The data presented in this catalogue are the results of multicolor photometric observations of stars listed in the Bright Star Catalog. Observations were made on the 21-in, 28-in and 60-in telescopes of the Lunar and Planetary Laboratory, and at Tonanzintla Observatory on the 40-in telescope of the Observatorio Astronomico Nacional, Universidad Nacional de Mexico. This catalog of UBV photometry on almost 5000 bright stars covers the entire sky by including southern Cape photometry transformed to the UBV system.
We present UBV photometric observations of 55 wide visual double stars with K- and M- type primaries. Our observations have been compared and combined with information available in the literature. At least 58% of them are optical pairs.
UBV measurements of early-type stars, mostly eclipsing binaries, obtained at La Silla in the years 1990 to 1994 with the ESO 50cm telescope are presented. Most of these data were already used in our individual studies of several binaries. Now all photometric measurements were reduced again with an advanced technique and are made available electronically. Our data for MY Ser have not yet been published; new light curve is given and solved. The result is that MY Ser is a contact binary, with very large fill-out parameter. Also a light curve and its solution for V1051 Cen are provided, and the problem of the period of V871 Cen is pointed out. Besides binaries (and the comparison and check stars) data for several stars in southern H II regions are included. Extinction and transformation coefficients are given.
We present all available UBV photometry of the symbiotic binary EG And obtained during the last 10 years. The light curves display a double wave through one orbital cycle. It is shown that this behaviour cannot be explained by eclipses of the two detached sources of the continuum radiation. The present models of EG And are not able to simulate satisfactorily variation in both the far ultraviolet and the optical continuum.
This catalog is the result of a program of photographic photometry. Four plates each were taken of M67 in U, B, and V, and were measured and reduced using the standards of Johnson and Sandage (1955) and Eggen and Sandage (1964). The catalog lists identification, V, B-V, U-B, proper motion, and membership probability for 1,053 stars.
The rapidly rotating active stars FK Com and HD 199178 are investigated using extensive long-term photometry. The data set includes previously unpublished photometry, obtained at the Rozhen National Astronomical Observatory. We look for periodicities in the long-term photometric behaviour of both stars, as well as for spots, using light curve modelling. Special attention is paid to the behaviour of the "flip-flop" phenomenon.
The observations were acquired in two nights, 1993 December 20-22, with the EMMI camera on the NTT telescope at ESO. The photometric limit is close to the cluster main-sequence turnoff; a comparison of the photometry with Walker (1990AJ....100.1532W) shows slight systematic differences . the present magnitudes being fainter by 0.03-0.05mag, and colors being bluer by 0.05mag. The estimated parameters of the populous globular cluster NGC 1841, located approximately 15deg from each of the Magellanic Clouds and probably dynamically associated with the LMC, are: [Fe/H] = -2.0 +/- 0.15 E(B-V) = 0.17 +/- 0.03 mag (m-M)_0_ = 18.26 +/- 0.11 mag (true distance modulus)
After a serendipitious discovery that HD 143418 is a light variable, we analyzed numerous UBV observations and Hipparcos H_p_ magnitudes transformed to Johnson V to find out whether the object is a very unusual spectroscopic binary. Initial reductions of new photometry were carried out with the HEC22 program, while the new spectra were reduced in the IRAF and SPEFO programs. Orbital elements were derived with the FOTEL program, the KOREL disentangling was applied, and period searches were carried out using phase dispersion minimalization technique and the program PERIOD04. Final modeling of radial-velocity and light variations was carried out in PHOEBE.
