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Despite the continuing importance of ground-based parallax measurements, few active programs remain. Because new members of the solar neighborhood tend towards later spectral types, infrared parallax programs are particularly desirable.…

Instrumentation and Methods for Astrophysics · Physics 2014-11-20 Jennifer Lynn Bartlett , Chan Park , Srikrishna Kanneganti , Philip A. Ianna

An extensive sample of M, L and T dwarfs identified in the Sloan Digital Sky Survey (SDSS) has been compiled. The sample of 718 dwarfs includes 677 new objects (629 M dwarfs, 48 L dwarfs) together with 41 that have been previously…

Astrophysics · Physics 2019-08-15 S. L. Hawley , K. R. Covey , G. R. Knapp , D. A. Golimowski , X. Fan

We present optical spectroscopy and near-infrared photometry of 126 cool white dwarfs in the Sloan Digital Sky Survey (SDSS). Our sample includes high proper motion targets selected using the SDSS and USNO-B astrometry and a dozen…

We describe a population of compact objects in the centre of the Fornax Cluster which were discovered as part of our 2dF Fornax Spectroscopic Survey. These objects have spectra typical of old stellar systems, but are unresolved on…

Astrophysics · Physics 2015-06-24 M. J. Drinkwater , J. B. Jones , M. D. Gregg , S. Phillipps

Our VLT (FLAMES) observations near NGC1399 investigate the connection between ultra-compact dwarf galaxies (UCDs), NGC1399 globular clusters and intra-cluster globulars. We have uncovered 30 faint compact stellar systems in the Fornax…

We report high resolution optical speckle observations of 336 M dwarfs which result in 113 measurements of relative position of 80 systems and 256 other stars with no indications of duplicity. These are the first measurements for two of the…

Solar and Stellar Astrophysics · Physics 2018-05-16 Brian D. Mason , William I. Hartkopf , Korie N. Miles , John P. Subasavage , Deepak Raghavan , Todd J. Henry

We present first results from the Palomar Adaptive Optics Survey of Young Stars conducted at the Hale 5 m telescope. Through direct imaging we have discovered a brown dwarf and two low-mass stellar companions to the young solar-type stars…

Astrophysics · Physics 2009-11-10 Stanimir A. Metchev , Lynne A. Hillenbrand

A photometric and spectroscopic analysis of 152 cool white dwarf stars is presented. The discovery of 7 new DA white dwarfs, 2 new DQ white dwarfs, 1 new magnetic white dwarf, and 3 weak magnetic white dwarf candidates, is reported, as well…

Astrophysics · Physics 2009-10-31 P. Bergeron , S. K. Leggett , Maria Teresa Ruiz

We report the discovery of 39 Faint High Latitude Carbon Stars (FHLCs) from Sloan Digital Sky Survey commissioning data. The objects, each selected photometrically and verified spectroscopically, range over 16.6 < r* < 20.0, and show a…

We have discovered a new type of galaxy in the Fornax Cluster: ``ultra-compact'' dwarfs (UCDs). The UCDs are unresolved in ground-based imaging and have spectra typical of old stellar systems. Although the UCDs resemble overgrown globular…

We present the results of a spectroscopic survey of 675 bright (16.5<Bj<18) galaxies in a 6 degree field centred on the Fornax cluster with the FLAIR-II spectrograph on the UK Schmidt Telescope. We measured redshifts for 516 galaxies of…

Astrophysics · Physics 2009-11-06 M. J. Drinkwater , M. D. Gregg , B. A. Holman , M. J. I. Brown

We present preliminary trigonometric parallaxes of 184 late-T and Y dwarfs using observations from Spitzer (143), USNO (18), NTT (14), and UKIRT (9). To complete the 20-pc census of $\ge$T6 dwarfs, we combine these measurements with…

We present 916 trigonometric parallaxes and proper motions of newly discovered nearby stars from the United States Naval Observatory (USNO) Robotic Astrometric Telescope (URAT). Observations were taken at the Cerro Tololo Interamerican…

Solar and Stellar Astrophysics · Physics 2018-02-26 Charlie Finch , Norbert Zacharias , Wei-Chun Jao

A search of more than 3,000 square degrees of high latitude sky by the Sloan Digital Sky Survey has yielded 251 faint high-latitude carbon stars (FHLCs), the large majority previously uncataloged. We present homogeneous spectroscopy,…

We investigate and parameterise high proper motion red stars in the Torino Observatory Parallax Program. Observations of 27 objects were made over the period 1994 - 2001 on the 1.05m Torino telescope. The trigonometric parallaxes and proper…

Solar and Stellar Astrophysics · Physics 2015-05-18 R. L. Smart , G. Ioannidis , H. R. A. Jones , B. Bucciarelli , M. G. Lattanzi

We report final results from our 2.5 year infrared parallax program carried out with the European Southern Observatory 3.5m New Technology Telescope and the SOFI infrared camera. Our program targeted precision astrometric observations of…

Astrophysics · Physics 2008-11-26 C. G. Tinney , Adam J. Burgasser , J. Davy. Kirkpatrick

We analyze 5108 AFGKM stars with at least five high precision radial velocity points as well as Gaia and Hipparcos astrometric data utilizing a novel pipeline developed in previous work. We find 914 radial velocity signals with periods…

The Vera C. Rubin Observatory's Legacy Survey of Space and Time (LSST) has the potential to measure parallaxes for thousands of nearby ultracool dwarfs, enabling improved measurements of the brown dwarf luminosity function. We develop a…

Solar and Stellar Astrophysics · Physics 2022-11-30 John E. Gizis , Peter Yoachim , R. Lynne Jones , Dylan Hilligoss , Jinbiao Ji

Hipparcos astrometric binaries were observed with the NICI adaptive optics system at Gemini-S, completing the work of Paper I (Tokovinin et al. 2012). Among the 65 F, G, K dwarfs within 67pc of the Sun studied here, we resolve 18 new…

Solar and Stellar Astrophysics · Physics 2015-06-15 Andrei Tokovinin , Markus Hartung , Thomas L. Hayward

We have identified 109 White Dwarf (WD) - M dwarf pairs in the Sloan Digital Sky Survey (SDSS) with g < 20th magnitude. For each system we determined the temperature of the WD primary and the spectral type of the M dwarf secondary. Using…