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A Star Catalog for the Open Cluster NGC 188
Stetson, Peter B.; VandenBerg, Don A.; McClure, Robert D.
We present new BVRI broadband photometry for the old open cluster NGC 188, based on an analysis of 299 CCD images either obtained by us, donated by colleagues, or retrieved from public archives. We compare our results on a star-by-star basis with data from 11 previous photometric data sets for the cluster. We homogenize and merge the data from all…
The Ultraviolet and Optical Spectra of Luminous B-Type Stars in the Small Magellanic Cloud
Lennon, D. J.; Evans, C. J.; Walborn, N. R. +2 more
We present ultraviolet spectra from the Space Telescope Imaging Spectrograph (STIS) of 12 early B-type stars in the Small Magellanic Cloud (SMC), composed of nine supergiants and three giants. A morphological comparison with Galactic analogs is made using archival data from the International Ultraviolet Explorer (IUE). In general, the intensity of…
New Light Curves and Orbital Solution for AM Leonis
Terrell, Dirk; Hiller, Mary E.; Osborn, Wayne
New UBVRI photometry has been obtained for the W UMa eclipsing system AM Leonis. The data have been used to derive nine times of minimum and to construct light curves. The minimum timings show that the system recently had a significant period increase. Modeling of the light curves shows AM Leo to be an overcontact system with a mass ratio of 2.51.…
Short-Period Variable Be Stars Discovered or Confirmed through Self-Correlation Analysis of Hipparcos Epoch Photometry
Percy, John R.; Harlow, Christopher D. W.; Wu, Alice P. S.
We have surveyed 277 bright Be stars for short-period (0.2-2 day) photometric variability using self-correlation analysis of Hipparcos epoch photometry. This extends the work of Percy et al.; the methods are as described there. We report the discovery, timescale, and amplitude of short-period variability in: HD 7636 (V764 Cas), HD 11606 (V777 Cas)…
Stellar Populations in the Outer Reaches of M31 and M32 from WFPC2 Photometry
Mateo, Mario; Alonso-García, Javier; Worthey, Guy +1 more
Hubble Space Telescope Wide Field Planetary Camera 2 photometry in a field 7 effective radii from the nucleus of M32 and a comparison field in the outer disk of M31, already examined for the presence of RR Lyrae variable stars, are further compared. No relative distance difference between the two fields could be measured using the luminosity of re…
Dwarf Novae with Newly Determined Parallaxes: Model Analyses of VY Aquarii, RU Pegasi, and T Leonis
Sion, E. M.; Hamilton, R. T.
Using newly determined parallaxes for dwarf novae, we have derived outburst accretion rates for VY Aqr, RU Peg, and T Leo, and for T Leo during quiescence. The two short-period dwarf novae, VY Aqr and T Leo, show good agreement with optically thick steady-state accretion disks in outburst, whereas RU Peg shows a significant departure from a steady…
A Far-Ultraviolet Spectroscopic Analysis of the Central Star of the Planetary Nebula Longmore 1
Bianchi, L.; Herald, J. E.
We have performed a non-LTE spectroscopic analysis using far-UV and UV data of the central star of the planetary nebula K1-26 (Longmore 1) and found Teff=120+/-10 kK, logg=6.7+0.3-0.7 cm s-2, and Y~=0.10. The temperature is significantly hotter than previous results based on optical line analyses, highli…
Newly Identified Star Clusters in NGC 6822, and the Age Distribution of Its Cluster System
Hodge, Paul; Krienke, Karl
From past ground-based imaging and our current Hubble Space Telescope images, we have identified 51 candidate open clusters in the dwarf irregular galaxy NGC 6822. Of these, 25 candidates are located on our HST images with standard wideband filters, 16 of which are securely identified as true clusters. Integrated photometry in B, V, and I for seve…
The Large Binocular Camera Image Simulator
Fontana, A.; Grazian, A.; Giallongo, E. +3 more
The Large Binocular Camera Image Simulator (LBCImSim) is a package for generating artificial images in the typical FITS format. It operates on real or artificial images, simulating the expected performances of real instruments by including several observing conditions (filters, air mass, flat field, and exposure time) and creating images with the …
Calibration of Hubble Space Telescope Advanced Camera for Surveys Emission-Line Filters
O'Dell, C. R.
The most commonly used narrowband filters of the Advanced Camera for Surveys (ACS) on the Hubble Space Telescope do not allow the clear delineation of individual emission lines as done with the more narrow field-of-view Wide Field and Planetary Camera. However, we have determined the calibration characteristics that allow separation of the Hα and …