The photometric and spectroscopic observations of IRAS 18062+2410 = V886 Her, a candidate for protoplanetary objects, in 1996-1997 are presented. The star exhibits rapid light variations with an amplitude up to 0.3mag in V. A high-resolution spectrum of IRAS shows absorption lines of H, HeI, OI, FeII, SiII, NaI and other species, including [OII], [NII], and [FeII] that belong to the stellar envelope.
Blue-violet spectrograms of individual components in four compact OB groups of the Large Magellanic Cloud, obtained with the Hubble Space Telescope (HST) Faint Object Spectrograph (FOS), are presented and discussed. Two of the massive multiple systems are in the 30 Doradus periphery, while the other two represent the core and the peripheral, triggered associations in the giant shell H II region Henize N11. Uncontaminated spectrograms of three Wolf-Rayet and two very early Of components have been obtained for the first time; they can be observed only as composites with their close companions from the ground. Many of the companions have also been observed separately with the HST FOS, and several are of special interest in their own right. These observations provide information on the initial masses and ages of the peculiar objects, and on the evolutionary relationships among different spectral categories within the presumably coeval systems.
UBV photometry of 955 galactic foreground stars in the direction to the Large Magellanic Cloud is presented. The stars have been chosen from foreground star catalogues and have been measured to complete a new data base containing entries of more than 5000 stars in the direction of the LMC. First and second order extinction coefficients at La Silla/Chile are given, which differ from the standard values because of the 1991 eruption of the volcano Mt. Pinatubo.
New UBV photometry for 878 luminous member stars of the Large Magellanic Cloud (LMC) and 13 stars of uncertain membership is presented. Including former observations now UBV data are available for altogether 2470 luminous LMC stars and 2106 foreground stars plus 65 stars of uncertain membership. The observations have been used already for several investigations dealing e.g. with interstellar reddening lines and intrinsic colours, the dust distribution and the calibration of charge-coupled device exposures.
Using ultraviolet photometry from the Ultraviolet Imaging Telescope (UIT) combined with photometry and spectroscopy from three ground-based optical data sets we have analyzed the stellar content of OB associations and field areas in and around the regions N79, N81, N83, and N94 in the Large Magellanic Cloud. In particular, we compare data for the OB association Lucke-Hodge 2 (LH 2) to determine how strongly the initial mass function (IMF) may depend on different photometric reductions and calibrations.
Photometric observations of LQ Hya (HD 82558) obtained in 1995-2001 with the Phoenix 10 robotic telescope (Arizona) in the UBV bands with HD 82447 as the comparison star.
We present photoelectric UBV photometry for some 2600 metal-poor dwarf and giant candidates selected from the HK objective-prism/interference-filter survey of Beers and colleagues. These data provide the basis for our ultraviolet-excess selection of objects having [Fe/H]{<~}-2.0 for a spectroscopic investigation in which we have obtained ~1-2{AA} resolution spectra of some 1000 objects. The present material may also prove useful for investigations of the metal-poor dwarfs and giants more metal-rich than [Fe/H]=-2.0, as well as the misclassified subdwarf O and B stars, white dwarfs, blue metal-poor stars, and field horizontal-branch stars which appear in the catalog.
We present results of an extensive photometric monitoring campaign of the peculiar emission star MWC 560 that covers the range 1990-1995. The time interval corresponds to the length of the proposed orbital period of this highly peculiar binary, which attracted considerable interest in January-April 1990, when absorption components, shifted by -6000km/s from corresponding emission lines, were observed. Here we present photometric data secured during: 113 nights of conventional UBV photoelectric photometry, 45 nights of high speed UBV photoelectric photometry to study the flickering activity, and 682 visual photometric estimates. MWC 560 has experienced a decrease in magnitude since the bright (V=9.2mag) phase in 1990. After the minimum reached in May 1994 (V=10.7mag), the star is currently increasing slowly in brightness. The decrease has been accompanied in all bands by large fluctuations superimposed on the mean trend. The B-V colour has shown a steady increase by 0.0.33mag/yr. U-B has remained stable at -0.07mag since late 1990. In all the observing nights devoted to high speed photometry we observed flickering activity in MWC 560. The data show that the flickering amplitude {DELTA}U increases with the decrease of the U magnitude. Quasi-periodic variations have always been detected. A period of ~70min has been observed in ~13 nights which is close to the ~60min quasi-period reported by Michalitsianos et al. (1993). However, no coherent variability is traceable throughout the whole set of flickering data.
UBV and DDO photoelectric photometry in the field of the open cluster NGC 2323 is presented. The analysis yields 109 probable members; one of them being a red giant, and 3 possible members. The basic cluster parameters are derived. NGC 2323 appears not to be physically connected to the CMa OB1 association.
Photoelectric UBV values, derived from observations made at the Boyden and ESO observatories, are presented for 358 early-type stars in the Vela section of the southern Milky Way. Remarks, accurate positions and notes have been added in July 2016 at CDS (Francois Ochsenbein)
