Contingut
Imatges
Carregar la teva Imatge
DSS Images Other Images
Articles Relacionats
A Catalog of Northern Stars with Annual Proper Motions Larger than 0.15" (LSPM-NORTH Catalog)
The LSPM catalog is a comprehensive list of 61,977 stars north of theJ2000 celestial equator that have proper motions larger than 0.15"yr-1 (local-background-stars frame). The catalog has beengenerated primarily as a result of our systematic search for high propermotion stars in the Digitized Sky Surveys using our SUPERBLINK software.At brighter magnitudes, the catalog incorporates stars and data from theTycho-2 Catalogue and also, to a lesser extent, from the All-SkyCompiled Catalogue of 2.5 million stars. The LSPM catalog considerablyexpands over the old Luyten (Luyten Half-Second [LHS] and New LuytenTwo-Tenths [NLTT]) catalogs, superseding them for northern declinations.Positions are given with an accuracy of <~100 mas at the 2000.0epoch, and absolute proper motions are given with an accuracy of ~8 masyr-1. Corrections to the local-background-stars propermotions have been calculated, and absolute proper motions in theextragalactic frame are given. Whenever available, we also give opticalBT and VT magnitudes (from Tycho-2, ASCC-2.5),photographic BJ, RF, and IN magnitudes(from USNO-B1 catalog), and infrared J, H, and Ks magnitudes(from 2MASS). We also provide an estimated V magnitude and V-J color fornearly all catalog entries, useful for initial classification of thestars. The catalog is estimated to be over 99% complete at high Galacticlatitudes (|b|>15deg) and over 90% complete at lowGalactic latitudes (|b|>15deg), down to a magnitudeV=19.0, and has a limiting magnitude V=21.0. All the northern starslisted in the LHS and NLTT catalogs have been reidentified, and theirpositions, proper motions, and magnitudes reevaluated. The catalog alsolists a large number of completely new objects, which promise to expandvery significantly the census of red dwarfs, subdwarfs, and white dwarfsin the vicinity of the Sun.Based on data mining of the Digitized Sky Surveys (DSSs), developed andoperated by the Catalogs and Surveys Branch of the Space TelescopeScience Institute (STScI), Baltimore.Developed with support from the National Science Foundation (NSF), aspart of the NASA/NSF NStars program.
| A Search for Cool Subdwarfs: Stellar Parameters for 134 Candidates
The results of a search for cool subdwarfs are presented. Kinematic (U,V, and W) and stellar parameters (Teff, logg, [Fe/H], andξt) are derived for 134 candidate subdwarfs based onhigh-resolution spectra. The observed stars span 4200K
| 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.
| Subdwarf studies. I - UBVRI photometry of NLTT stars
UBVRI photometry is presented for a sample of 1656 southern stars,including 1211 that were previously unmeasured, drown from the NLTTproper-motion catalog. The catalog is shown to be a rich source ofsubdwarfs. The normalized ultraviolet excess delta (U - B)0.6,photometric parallax, and interstellar reddening are calculated for eachstar when possible. Photometric parallaxes are compared withtrigonometric parallaxes from the literature. It is found that theformer do not have systematic errors greater than about 25 percent. Inagreement with other studies, the bluest subdwarfs are found at B - V =0.35. The selection of the program stars on the basis of large reducedproper motions restricted subgiant contamination of the sample to about5 percent and increased the discovery fraction of halo stars relative todisk stars. The claim is made here that the sample can be used toinvestigate the abundance distribution of the halo. The sample includesstars with ultraviolet excesses characteristic of disk abundances butwith velocities up to 150 km/s. These are believed to be stars that,quite expectedly, reside in the high-velocity tail of the disk velocitydistribution.
| Photometry of dwarf K and M stars
Broadband photometry in BVRI colors for 120 nearby dwarf K and M starsis presented. The apparent magnitude distributions of Vyssotsky and VanVleck stars with photometry and without photometry are studied. Therelationship between apparent and photoelectric magnitudes is analyzed.The proper motion and transverse velocity of the two star types areexamined and compared.
| Dwarf K and M stars of high proper motion found in a hemispheric survey
A recently completed visual/red spectral region objective-prism surveyof more than half the sky found some 2200 dwarf K and M stars ofnegligible proper motion (Stephenson, 1986). The present paper adds the1800-odd spectroscopically identified dwarfs that did prove to havesignificant proper motions. About half of these had previous spectralclassifications of some sort, especially by Vyssotsky (1952, 1956). Forthe great majority, the present coordinates are more accurate thanprevious data. The paper includes about 50 stars with unpublishedparallaxes, likely to have parallaxes of 0.05 arcsec or more. Combiningthe present data with the first paper suggests that the number oflow-proper-motion stars in that paper was not unreasonable.
| Photovisual magnitudes of 418 dwarf M stars and 34 parallax stars.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1956AJ.....61..219S&db_key=AST
| Dwarf M stars found spectrophotometrically .
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1956AJ.....61..201V&db_key=AST
|
Enviar un nou article
Enllaços Relacionats
- - No s'ha trobat enllaços -
Enviar un nou enllaç
Membre dels grups següents:
|
Dades d'Observació i Astrometria
| Constel·lació: | Cetus |
| Ascensió Recta: | 02h14m10.69s |
| Declinació: | +01°33'12.2" |
| Magnitud Aparent: | 10.902 |
| Moviment propi RA: | 200.8 |
| Moviment propi Dec: | 11.5 |
| B-T magnitude: | 12.244 |
| V-T magnitude: | 11.013 |
Catàlegs i designacions:
|
INHABITED SKY
