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The Fourth US Naval Observatory CCD Astrograph Catalog (UCAC4)
Zacharias, N.; Finch, C. T.; Girard, T. M. +4 more
The fourth United States Naval Observatory (USNO) CCD Astrograph Catalog, UCAC4, was released in 2012 August (double-sided DVD and CDS data center Vizier catalog I/322). It is the final release in this series and contains over 113 million objects; over 105 million of them with proper motions (PMs). UCAC4 is an updated version of UCAC3 with about t…
Space Velocities of Southern Globular Clusters. VII. NGC 6397, NGC 6626 (M28), and NGC 6656 (M22)
Casetti-Dinescu, Dana I.; Girard, Terrence M.; van Altena, William F. +3 more
We have measured the absolute proper motions of globular clusters NGC 6397, NGC 6626 (M22), and NGC 6656 (M28) as part of our ongoing Southern Proper-Motion Program. The reference system is the ICRS via Hipparcos stars for these three low-Galactic-latitude clusters. Formal errors range between ~0.3 and 0.7 mas yr-1. Notable is the resul…
Hipparcos Photocentric Orbits of 72 Single-lined Spectroscopic Binaries
Ren, Shulin; Fu, Yanning
By fitting the Hipparcos Intermediate Astrometric Data (HIAD), photocentric orbits can be obtained for the single-lined spectroscopic binaries (SB1s). In previous work, a simplifying approximation used in the fitting process was that the photocenter coincides with the primary, but simple arguments based on a mass-luminosity relation show that this…
Very Low Mass Stellar and Substellar Companions to Solar-like Stars from MARVELS. IV. A Candidate Brown Dwarf or Low-mass Stellar Companion to HIP 67526
Bizyaev, Dmitry; Brewington, Howard; Ebelke, Garrett +50 more
We report the discovery of a candidate brown dwarf (BD) or a very low mass stellar companion (MARVELS-5b) to the star HIP 67526 from the Multi-object Apache point observatory Radial Velocity Exoplanet Large-area Survey (MARVELS). The radial velocity curve for this object contains 31 epochs spread over 2.5 yr. Our Keplerian fit, using a Markov Chai…
Companions to nearby Stars with Astrometric Acceleration. II
Tokovinin, Andrei; Hayward, Thomas L.; Hartung, Markus
Hipparcos astrometric binaries were observed with the NICI adaptive optics system at Gemini-S, completing the work of Paper I. Among the 65 F, G, and K dwarfs within 67 pc of the Sun studied here, we resolve 18 new subarcsecond companions, remeasure 7 known astrometric pairs, and establish the physical nature of yet another 3 wider companions. The…
Efficient Selection and Classification of Infrared Excess Emission Stars Based on AKARI and 2MASS Data
Zeng Li, Jin; Rector, Travis A.; Huang, Ya Fang +1 more
The selection of young stellar objects (YSOs) based on excess emission in the infrared is easily contaminated by post-main-sequence stars and various types of emission line stars with similar properties. We define in this paper stringent criteria for an efficient selection and classification of stellar sources with infrared excess emission based o…