CCD Parallaxes for 309 Late-type Dwarfs and Subdwarfs

Journal Article · Sun Oct 01 00:00:00 EDT 2017 · Astronomical Journal (Online)

DOI:https://doi.org/10.3847/1538-3881/AA880B· OSTI ID:22663145

Dahn, Conard C.; Harris, Hugh C.; Subasavage, John P.; Ables, Harold D.; Guetter, Harry H.; Harris, Fred H.; Luginbuhl, Christian B.; Monet, Alice B.; Monet, David G.; Munn, Jeffrey A.; Pier, Jeffrey R.; Stone, Ronald C.; Vrba, Frederick J.; Walker, Richard L.; Tilleman, Trudy M. ^[1]; Canzian, Blaise J. ^[2]; Henden, Arne H. ^[3]; Leggett, S. K. ^[4]

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1. US Naval Observatory, Flagstaff Station, 10391 W. Naval Observatory Road, Flagstaff, AZ 86005-8521 (United States)
2. L-3 Communications/Brashear, 615 Epsilon Drive, Pittsburgh, PA 15238-2807 (United States)
3. AAVSO, Cambridge, MA 02138 (United States)
4. Gemini Observatory, Northern Operations Center, 670 N. A’ohoku Place, Hilo, HI 96720 (United States)

New, updated, and/or revised CCD parallaxes determined with the Strand Astrometric Reflector at the Naval Observatory Flagstaff Station are presented. Included are results for 309 late-type dwarf and subdwarf stars observed over the 30+ years that the program operated. For 124 of the stars, parallax determinations from other investigators have already appeared in the literature and we compare the different results. Also included here are new or updated VI photometry on the Johnson–Kron-Cousins system for all but a few of the faintest targets. Together with 2MASS JHK{sub s} near-infrared photometry, a sample of absolute magnitude versus color and color versus color diagrams are constructed. Because large proper motion was a prime criterion for targeting the stars, the majority turn out to be either M-type subdwarfs or late M-type dwarfs. The sample also includes 50 dwarf or subdwarf L-type stars, and four T dwarfs. Possible halo subdwarfs are identified in the sample based on tangential velocity, subluminosity, and spectral type. Residuals from the solutions for parallax and proper motion for several stars show evidence of astrometric perturbations.

• OSTI ID: 22663145
• Journal Information: Astronomical Journal (Online), Vol. 154, Issue 4; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 1538-3881
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
CHARGE-COUPLED DEVICES
COLOR
COMPARATIVE EVALUATIONS
DIAGRAMS
DISTANCE
DISTURBANCES
DWARF STARS
NEAR INFRARED RADIATION
PHOTOMETRY
PROPER MOTION
VELOCITY