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Astrometry and Photometry for Cool Dwarfs and Brown Dwarfs
Kirkpatrick, J. Davy; Burgasser, Adam J.; Gizis, John E. +15 more
Trigonometric parallax determinations are presented for 28 late-type dwarfs and brown dwarfs, including eight M dwarfs with spectral types between M7 and M9.5, 17 L dwarfs with spectral types between L0 and L8, and three T dwarfs. Broadband photometry at CCD wavelengths (VRIz*) and/or near-IR wavelengths (JHK) is presented for these objects and fo…
Exploring the Full Stellar Population of the Upper Scorpius OB Association
Brown, Anthony G. A.; Zinnecker, Hans; Guenther, Eike +2 more
We investigate the stellar population and star formation history of the Upper Scorpius OB association, the most nearby region of recent massive star formation, over the full stellar mass range from 0.1 to 20 Msolar. The first part of this paper describes an extension of our large spectroscopic survey (Preibisch et al., published in 2001…
Post-T Tauri Stars in the Nearest OB Association
Meyer, Michael R.; Mamajek, Eric E.; Liebert, James
We present results of a spectroscopic survey of X-ray- and proper-motion-selected samples of late-type stars in the Lower Centaurus-Crux (LCC) and Upper Centaurus-Lupus (UCL) subgroups of the nearest OB association: Scorpius-Centaurus. The primary goals of the survey are to determine the star formation history of the OB subgroups and to assess the…
The Palomar/MSU Nearby Star Spectroscopic Survey. IV. The Luminosity Function in the Solar Neighborhood and M Dwarf Kinematics
Hawley, Suzanne L.; Gizis, John E.; Reid, I. Neill
We have used new astrometric and spectroscopic observations to refine the volume-complete sample of M dwarfs defined in previous papers in this series. With the addition of Hipparcos astrometry, our revised VC2 sample includes 558 main-sequence stars in 448 systems. Analysis of that data set shows no evidence of any systematic kinematic…
The Star Formation History and Spatial Distribution of Stellar Populations in the Ursa Minor Dwarf Spheroidal Galaxy
Aparicio, Antonio; Martínez-Delgado, David; Alonso-García, Javier +1 more
As a part of a project devoted to the study of the Ursa Minor dwarf spheroidal (dSph) galaxy, the star formation history of the galaxy is presented. The analysis uses wide-field photometry, encompassing about 1°×1° (the total covered area being 0.75 deg2), which samples the galaxy out to its tidal radius. Derivation of the star formatio…
WIYN Open Cluster Study. X. The K-Band Magnitude of the Red Clump as a Distance Indicator
Sarajedini, Ata; Grocholski, Aaron J.
In an effort to improve the utility of the helium-burning red clump luminosity as a distance indicator, we explore the sensitivity of the K-band red clump absolute magnitude [MK(RC)] to metallicity and age. We rely upon JK photometry for 14 open clusters and two globular clusters from the Second Incremental Data Release of the Two Micro…
New High Proper Motion Stars from the Digitized Sky Survey. I. Northern Stars with 0.5" yr-1<µ<2.0" yr-1 at Low Galactic Latitudes
Lépine, Sébastien; Rich, R. Michael; Shara, Michael M.
We have conducted a systematic search for high proper motion stars in the Digitized Sky Survey, in the area of the sky north of -2.8 degrees in declination and within 25 degrees of the Galactic plane. Using the SUPERBLINK software, a powerful automated blink comparator developed by us, we have identified 601 stars in the magnitude range 9<r<…
Metal Abundances and Kinematics of Bright Metal-poor Giants Selected from the LSE Survey: Implications for the Metal-weak Thick Disk
Beers, Timothy C.; von Hippel, Ted; Rossi, Silvia +5 more
We report medium-resolution (1-2 Å) spectroscopy and broadband (UBV) photometry for a sample of 39 bright stars (the majority of which are likely to be giants) selected as metal-deficient candidates from an objective-prism survey concentrating on Galactic latitudes below |b|=30°, the Luminous Stars Extension (LSE) survey of Drilling & Bergeron…
Radial Velocity Studies of Close Binary Stars. VI.
Rucinski, Slavek M.; Capobianco, Christopher C.; Lu, Wenxian +5 more
Radial velocity measurements and sine-curve fits to the orbital velocity variations are presented for the sixth set of 10 close binary systems: SV Cam, EE Cet, KR Com, V410 Cyg, GM Dra, V972 Her, ET Leo, FS Leo, V2388 Oph, and II UMa. All systems except FS Leo are double-lined spectroscopic binaries. The type of FS Leo is unknown, while SV Cam is …
The Distance Scale for Classical Cepheid Variables
Turner, David G.; Burke, James F.
New radii, derived from a modified version of the Baade-Wesselink (BW) method that is tied to published KHG narrowband spectrophotometry, are presented for 13 bright Cepheids. The data yield a best-fitting period-radius relation given by log<R/Rsolar>=1.071(+/-0.025)+0.747(+/- 0.028)logP0. In combination with other high…