Search Publications
The Effect of the Outer Lindblad Resonance of the Galactic Bar on the Local Stellar Velocity Distribution
Dehnen, Walter
Hydrodynamic modeling of the inner Galaxy suggests that the radius of the outer Lindblad resonance (OLR) of the Galactic bar lies in the vicinity of the Sun. How does this resonance affect the distribution function in the outer parts of a barred disk, and can we identify any effect of the resonance in the velocity distribution actually observed in…
Abundances and Kinematics of Field Halo and Disk Stars. I. Observational Data and Abundance Analysis
Fulbright, Jon P.
We describe observations and abundance analysis of a high-resolution, high signal-to-noise ratio survey of 168 stars, most of which are metal-poor dwarfs. We follow a self-consistent LTE analysis technique to determine the stellar parameters and abundances, and we estimate the effects of random and systematic uncertainties on the resulting abundan…
Kinematics of Metal-poor Stars in the Galaxy. II. Proper Motions for a Large Nonkinematically Selected Sample
Beers, Timothy C.; Rossi, Silvia; Platais, Imants +4 more
We present a revised catalog of 2106 Galactic stars, selected without kinematic bias and with available radial velocities, distance estimates, and metal abundances in the range -4.0<=[Fe/H]<=0.0. This update of the 1995 Beers & Sommer-Larsen catalog includes newly derived homogeneous photometric distance estimates, revised radial velocit…
The First US Naval Observatory CCD Astrograph Catalog
Zacharias, N.; Urban, S. E.; Wycoff, G. L. +9 more
The USNO CCD Astrograph (UCA) started an astrometric survey in 1998 February at Cerro Tololo, Chile. This first, preliminary catalog (UCAC1) includes data taken up to 1999 November with about 80% of the Southern Hemisphere covered. Observing continues, and full sky coverage is expected by mid-2003 after moving the instrument to a Northern Hemisphe…
Radial Velocity Studies of Close Binary Stars. III
Rucinski, Slavek M.; Lu, Wenxian; Mochnacki, Stefan W.
Radial velocity measurements and simple sine-curve fits to the orbital velocity variations are presented for the third set of 10 close binary systems: CN And, HV Aqr, AO Cam, YY CrB, FU Dra, RZ Dra, UX Eri, RT LMi, V753 Mon, and OU Ser. All systems except two (CN And and RZ Dra) are contact, double-line spectroscopic binaries, with four of them (Y…
Binary Star Differential Photometry Using the Adaptive Optics System at Mount Wilson Observatory
Bagnuolo, William G., Jr.; Mason, Brian D.; ten Brummelaar, Theo +4 more
We present photometric and astrometric results for 36 binary systems observed with the natural guide star adaptive optics system of the Mount Wilson Institute on the 100 inch (2.5 m) Hooker Telescope. The measurements consist of differential photometry in U, B, V, R, and I filters along with astrometry of the relative positions of system component…
A Distance-Independent Age for the Globular Cluster M92
Grundahl, F.; Stetson, P. B.; Andersen, M. I. +2 more
We use deep Strömgren CCD photometry to determine the age of the globular cluster M92 (NGC 6341) from the [(v-y)0,c0]-diagram. Besides being completely independent of distance, this color-color plot has the further advantage that it is not very sensitive to the amount of foreground interstellar absorption. The main disadvanta…
The Tip of the Red Giant Branch Distance to the Large Magellanic Cloud
Zaritsky, Dennis; Sakai, Shoko; Kennicutt, Robert C., Jr.
We present the I-band luminosity function of the red giant branch stars in the Large Magellanic Cloud (LMC) using the data from the Magellanic Clouds Photometric Survey (MCPS). By selecting stars in uncrowded, low-extinction regions, we observe a discontinuity in the luminosity function at I0=14.54 mag. Identifying this feature with the…
The Near-Ultraviolet Continuum of Late-Type Stars
Lambert, David L.; Allende Prieto, Carlos
Analyses of the near-ultraviolet continuum of late-type stars have led to controversial results regarding the performance of state-of-the-art model atmospheres. The release of the homogeneous International Ultraviolet Explorer (IUE) final archive and the availability of the high-accuracy Hipparcos parallaxes provide an opportunity to revisit this …
CCD Speckle Observations of Binary Stars from the Southern Hemisphere. II. Measures from the Lowell-Tololo Telescope during 1999
Franz, Otto G.; Horch, Elliott; Ninkov, Zoran
Speckle observations of 145 double stars and suspected double stars are presented and discussed. On the basis of multiple observations, a total of 280 position angle and separation measures are determined, as well as 23 high-quality nondetections. All observations were taken with the (unintensified) Rochester Institute of Technology fast-readout C…