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A Catalog and Atlas of Cataclysmic Variables-Second Edition
Shara, Michael M.; Downes, Ronald; Webbink, Ronald F.
We present a catalog of all 1020 known cataclysmic variables (CVs). This paper is a major update of the first edition of the catalog (Downes and Shara 1993, PASP, 105, 127), which contained coordinates (measured in the reference frame of the Hubble Space Telescope Guide Star Survey for the non-novae, and obtained from the literature for the novae)…
The First Direct Measurement of the Mass of a Blue Straggler in the Core of a Globular Cluster: BSS 19 in 47 Tucanae
Livio, Mario; Saffer, Rex A.; Shara, Michael M.
Hot, young blue straggler stars are observed by the Hubble Space Telescope to exist in the cores of very old globular clusters. Theory maintains that these stars must be more massive than hydrogen-burning cluster members that are as old as the clusters themselves. We have, for the first time, verified this theoretical claim by directly measuring t…
The Dwarf Irregular Galaxy Sextans A. II. Recent Star Formation History
Skillman, Evan D.; Saha, A.; Gallagher, J. +6 more
We have used the Hubble Space Telescope to obtain photometric data of the resolved stars in the nearby (D = 1.4 Mpc) dwarf irregular galaxy Sextans A (DDO 75, A 1008-04). The data consist of WFPC2 images in 3 bands: F439W (1 hour), F555W (30 minutes), and F814W (30 minutes). We constructed very accurate color-magnitude diagrams (CMDs) in V and I d…
Hubble Space Telescope Observations of the Blue Compact Dwarf SBS 0335-052: A Probable Young Galaxy
Thuan, Trinh X.; Izotov, Yuri I.; Lipovetsky, Valentin A.
We present HST WFPC2 V and I images and GHRS UV spectrophotometry of the spectral regions around Lyα and O I λ1302 of the extremely metal-deficient (Z ~ Z⊙/41) blue compact dwarf galaxy (BCD) SBS 0335-052. All the star formation in the BCD occurs in six super-star clusters (SSCs) with ages <=25 Myr, within a region of ~2" or 520 pc i…
Carbon in the Diffuse Interstellar Medium
Sofia, Ulysses J.; Meyer, David M.; Cardelli, Jason A. +1 more
We have obtained spectra of the interstellar intersystem C II] λ2325 line toward the star τ Canis Majoris. The absorption spectra were obtained with the echelle mode (3.5 km s-1 resolution) of the Goddard High Resolution Spectrograph aboard the Hubble Space Telescope and have a co-added signal-to-noise ratio of approximately 850. The C …
Warm molecular envelope of M giants and Miras: a new molecule forming region unmasked by the ISO SWS.
Ohnaka, K.; Yamamura, I.; Tsuji, T. +1 more
Our observations with the ISO SWS revealed that H_2_O band at 2.7µm appears as absorption already in an M2 giant β Peg and strengthens towards later M giants. Further, CO_2_ 4.2µm band appears as absorption in an M7 giant SW Vir and especially strong in a Mira variable S Vir. The excitation temperatures of these molecular bands estimat…
The TYCHO Catalogue
Makarov, V. V.; Bastian, U.; Fabricius, C. +9 more
The principal observational characteristics of the Tycho Catalogue, and a summary of its main astrometric and photometric properties, are presented. Median astrometric standard errors (in position, parallax, and annual proper motion) are typically around 7mas for stars brighter than V_T_~9mag, and approximately 25mas for V_T_~10.5mag, at the catal…
Composition of Interstellar Clouds in the Disk and Halo. IV. HD 215733
Fitzpatrick, Edward L.; Spitzer, Lyman, Jr.
In this paper we continue our investigation of diffuse clouds in the interstellar medium with an analysis of the line of sight toward the star HD 215733, located in the Galactic halo some 1700 pc below the plane. As in our previous papers, we utilize the component-fitting technique to determine velocities, velocity widths, and column densities for…
Discovery of Interstellar Hydrogen Fluoride 1
Neufeld, David A.; Phillips, Thomas G.; Schilke, Peter +1 more
We report the first detection of interstellar hydrogen fluoride. Using the Long Wavelength Spectrometer of the Infrared Space Observatory (ISO), we have detected the 121.6973 µm J=2-1 line of HF in absorption toward the far-infrared continuum source Sagittarius B2. The detection is statistically significant at the 13 σ level. On the basis of…
β Pictoris revisited by Hipparcos. Star properties.
Crifo, F.; Ferlet, R.; Vidal-Madjar, A. +2 more
Observations with the Hipparcos satellite allowed a new determination of the β Pictoris distance. This star is located at 19.28+/-0.19pc, a value close to the upper limit of previous evaluations. The overall consequences are briefly discussed; in particular it is concluded that in the frame of standard stellar evolution models, there is no need fo…