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The Solar Neighborhood. XXV. Discovery of New Proper Motion Stars with 0farcs40 yr-1 > ? >= 0farcs18 yr-1 between Declinations -47° and 00°
We present 2817 new southern proper motion systems with 0farcs40yr-1 > ? >= 0farcs18 yr-1 and declinationbetween -47° and 00°. This is a continuation of theSuperCOSMOS-RECONS (SCR) proper motion searches of the southern sky. Weuse the same photometric relations as previous searches to providedistance estimates based on the assumption that the objects are singlemain-sequence stars. We find 79 new red dwarf systems predicted to bewithin 25 pc, including a few new components of previously knownsystems. Two systems—SCR 1731-2452 at 9.5 pc and SCR 1746-3214 at9.9 pc—are anticipated to be within 10 pc. We also find 23 newwhite dwarf (WD) candidates with distance estimates of 15-66 pc, as wellas 360 new red subdwarf candidates. With this search, we complete theSCR sweep of the southern sky for stars with ? >= 0farcs18yr-1 and R 59F <= 16.5, resulting in a totalof 5042 objects in 4724 previously unreported proper motion systems.Here we provide selected comprehensive lists from our SCR proper motionsearch to date, including 152 red dwarf systems estimated to be within25 pc (9 within 10 pc), 46 WDs (10 within 25 pc), and 598 subdwarfcandidates. The results of this search suggest that there are morenearby systems to be found at fainter magnitudes and lower proper motionlimits than those probed so far.
| Effective temperature scale and bolometric corrections from 2MASS photometry
We present a method to determine effective temperatures, angularsemi-diameters and bolometric corrections for population I and II FGKtype stars based on V and 2MASS IR photometry. Accurate calibration isaccomplished by using a sample of solar analogues, whose averagetemperature is assumed to be equal to the solar effective temperature of5777 K. By taking into account all possible sources of error we estimateassociated uncertainties to better than 1% in effective temperature andin the range 1.0-2.5% in angular semi-diameter for unreddened stars.Comparison of our new temperatures with other determinations extractedfrom the literature indicates, in general, remarkably good agreement.These results suggest that the effective temperaure scale of FGK starsis currently established with an accuracy better than 0.5%-1%. Theapplication of the method to a sample of 10 999 dwarfs in the Hipparcoscatalogue allows us to define temperature and bolometric correction (Kband) calibrations as a function of (V-K), [m/H] and log g. Bolometriccorrections in the V and K bands as a function of T_eff, [m/H] and log gare also given. We provide effective temperatures, angularsemi-diameters, radii and bolometric corrections in the V and K bandsfor the 10 999 FGK stars in our sample with the correspondinguncertainties.
| Improved Astrometry and Photometry for the Luyten Catalog. II. Faint Stars and the Revised Catalog
We complete construction of a catalog containing improved astrometry andnew optical/infrared photometry for the vast majority of NLTT starslying in the overlap of regions covered by POSS I and by the secondincremental Two Micron All Sky Survey (2MASS) release, approximately 44%of the sky. The epoch 2000 positions are typically accurate to 130 mas,the proper motions to 5.5 mas yr-1, and the V-J colors to0.25 mag. Relative proper motions of binary components are measured to 3mas yr-1. The false-identification rate is ~1% for11<~V<~18 and substantially less at brighter magnitudes. Theseimprovements permit the construction of a reduced proper-motion diagramthat, for the first time, allows one to classify NLTT stars intomain-sequence (MS) stars, subdwarfs (SDs), and white dwarfs (WDs). We inturn use this diagram to analyze the properties of both our catalog andthe NLTT catalog on which it is based. In sharp contrast to popularbelief, we find that NLTT incompleteness in the plane is almostcompletely concentrated in MS stars, and that SDs and WDs are detectedalmost uniformly over the sky δ>-33deg. Our catalogwill therefore provide a powerful tool to probe these populationsstatistically, as well as to reliably identify individual SDs and WDs.
| UVBY observations of A, F, G and K field stars
Photoelectric data in the uvby system have been obtained for about 800southern stars of the Hipparcos Input Catalog (Grenon, 1982, 1985). Mostof the stars are F and G main sequence and fall in the magnitude range V= 8-11.
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| Takýmyýldýz: | Tavsan |
| Sað Açýklýk: | 05h21m41.09s |
| Yükselim: | -16°09'31.7" |
| Görünürdeki Parlaklýk: | 10.301 |
| özdevim Sað Açýklýk: | 51.6 |
| özdevim Yükselim: | -192.8 |
| B-T magnitude: | 11.356 |
| V-T magnitude: | 10.389 |
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