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An Astrometric Study of the Binary Star α Ophiuchi
Gatewood, George
The work reported here combines data from the Multichannel Astrometric Photometer (MAP), the European astrometric satellite, Hipparcos, and infrared speckle observations of the nearby subgiant binary star system α Oph. The A5 IV primary is found to have a mass of 2.84+/-0.19 Msolar, while the approximately K2 V companion has a mass of 0…
A Possible High Nova Rate for Two Local Group Dwarf Galaxies: M32 and NGC 205
Shara, Michael M.; Neill, James D.
We report the results of a preliminary nova survey of Local Group dwarf elliptical galaxies. We used the 15' field-of-view CCD camera on the 0.8 m telescope at the Tenagra Observatory to observe M32, NGC 205, NGC 147, and NGC 185 in their entirety every clear night over a 4.5 month interval and discovered one nova in M32 and a candidate nova in NG…
Cluster Populations in Abell 2125 and 2218
Schombert, James; Rakos, Karl
We combine new narrowband photometry with archival Wide Field Planetary Camera 2 (WFPC2) data for A2218 (z=0.18) and A2125 (z=0.25), two clusters with intermediate redshifts but very different cluster properties, in order to examine the evolution of galaxy populations. A2218 is a dense, elliptical-rich cluster (Bautz-Morgan type II) similar to the…
The FIRST-Optical-VLA Survey for Lensed Radio Lobes
Muxlow, T. W. B.; Winn, Joshua N.; Kochanek, Christopher S. +7 more
We present results from a survey for gravitationally lensed radio lobes. Lensed lobes are a potentially richer source of information about galaxy mass distributions than lensed point sources, which have been the exclusive focus of other recent surveys. Our approach is to identify radio lobes in the Faint Images of the Radio Sky at Twenty cm (FIRST…
Spin-resolved Far-Ultraviolet Observations of the Magnetic White Dwarf in YY Draconis
Szkody, Paula; Sion, Edward M.; Hoard, D. W. +1 more
We observed the intermediate polar YY Draconis with the Far Ultraviolet Spectroscopic Explorer (FUSE), yielding an average far-UV spectrum, as well as spectra and spectrophotometric light curves resolved on the spin phase of the white dwarf in this system. We utilized the BINSYN software suite to calculate model spectra based on a simple system mo…
Orbit, Dynamical Mass, and MK Type of Visual Binary WOR 2
Docobo, J. A.; Balega, Y. Y.; Tamazian, V. S. +2 more
On the basis of new speckle measurements with the 6 m telescope of the Special Astrophysical Observatory (Russia) and Hipparcos astrometry, an improved orbital solution with a period of P=24.1 yr for the visual binary WOR 2 is obtained. The dynamical mass of the system is 1.40+/-0.25 Msolar. Differential photometry (Δm=0.55 mag) allowed…
Hubble Space Telescope Imaging of the WR 38/WR 38a Cluster
Gies, Douglas R.; Moffat, Anthony F. J.; Wallace, Debra J. +2 more
We are conducting a high angular resolution imaging survey of Galactic Wolf-Rayet stars using the Wide Field Planetary Camera 2 aboard the Hubble Space Telescope (HST). We have found a small stellar cluster associated with the faint, close pair WR 38 and WR 38a. We present astrometric measurements and photometry in the wide-band F336W (U), F439W (…
Hubble Space Telescope Observations of Star-forming Regions in NGC 3994/3995
Weistrop, D.; Eggers, D.; Stone, A. +2 more
We obtained ultraviolet and optical images of star-forming regions in the interacting galaxy system NGC 3994/3995 using the Space Telescope Imaging Spectrograph on the Hubble Space Telescope. We describe the characteristics of 56 detected knots, a majority of which are younger than 20 Myr old. There is no discernible pattern of knot age with respe…
Variable Star Candidates in an Advanced Camera for Surveys Field of M31
Williams, Benjamin F.
A search for variable stars is performed using two epochs of Hubble Space Telescope Advanced Camera for Surveys imaging data for a 9.28 arcmin2 portion of M31. This data set reveals 254 sources that vary by at least 4 σ between epochs. The positions and two-epoch B-band (equivalent) photometry of these sources are presented. The photome…
The Fine Guidance Sensor Orbit of the G4 Bright Giant HD 173764
Parsons, Sidney B.; Wasserman, Lawrence H.; Franz, Otto G.
TRANS and POS mode observations of the G4 IIa star β Scuti (HD 173764) have been made with a Hubble Space Telescope (HST) Fine Guidance Sensor (FGS3). This spectroscopic binary with a period of 833 days and an eccentricity of 0.36 offered hope of resolving the secondary stellar component and inferring the orbital inclination, distance, and masses,…