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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.
| Statistics of spectroscopic sub-systems in visual multiple stars
A large sample of visual multiples of spectral types F5-M has beensurveyed for the presence of spectroscopic sub-systems. Some 4200 radialvelocities of 574 components were measured in 1994-2000 with thecorrelation radial velocity meter. A total of 46 new spectroscopicorbits were computed for this sample. Physical relations are establishedfor most of the visual systems and several optical components areidentified as well. The period distribution of sub-systems has a maximumat periods from 2 to 7 days, likely explained by a combination of tidaldissipation with triple-star dynamics. The fraction of spectroscopicsub-systems among the dwarf components of close visual binaries withknown orbits is similar to that of field dwarfs, from 11% to 18% percomponent. Sub-systems are more frequent among the components of widevisual binaries and among wide tertiary components to the known visualor spectroscopic binaries - 20% and 30%, respectively. In triple systemswith both outer (visual) and inner (spectroscopic) orbits known, we findan anti-correlation between the periods of inner sub-systems and theeccentricities of outer orbits which must be related to dynamicalstability constraints. Tables 1, 2, and 6 are only available inelectronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr(130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/382/118
| Mass determination of astrometric binaries with Hipparcos. II. Selection of candidates and results
In a previous paper (\cite{Mar97}) we have shown that for double starswith orbital periods smaller than about 25 years, it was possible todetermine from the Hipparcos data, the mass ratio B of the components orthe difference between the mass and intensity ratios, beta -B, providedthe orbital elements of the relative orbit are available. From anextensive literature search we have selected 145 potential systems, ofwhich 46 yielded eventually a satisfactory solution. For eight systemswith the largest separations, the peculiarities of the natural directionassociated to the Hipparcos observations, the 'hippacentre', have beenfully exploited to derive the mass ratio of the components without anyadditional assumption. For the remaining 38, the derivation of the massratio was possible only by taking the magnitude difference between thetwo components from other sources. The parallax determinedsimultaneously, is then used to produce the individual masses of thecomponents. The astrophysical relevance of the results is discussed andwhen possible (17 systems) the masses are compared to ground-basedvalues.
| Orbital elements for twenty-eight visual binaries
In addition to presenting the orbital elements of 22 revised and six newpairs, attention is given to the ephemeris, dynamical parallax, and O-Cresiduals of each star. The stars are 148-BU 1026, 864-A 2308, 1315-HU531, 1530-A 2407, 2578-A 983, 3552-HU 1090, 6291-STF 1130, 6721-STF1211, 6814-HU 714, 7124-HU 718, 7896-A 2768, 8680-HU 640, 8884-A 2489,9185-A 1101, 10158-A 349, 10230-STT 315, 10531-HU 1179, 10912-STF 2244,1236-BU 1129, 12469-Schj 22, BD + 39 3878-Kpr 94, I12577-HU 951, 13169-A606, 14783-H 1 48, 15378-A 889, 15650-A 308, 15902-BU 172, and 17030-A424.
| Orbits of 15 visual binaries
Observations over the May 1981-May 1983 period are the bases of theorbital and physical data presented on 15 visual pairs which include theHyades triple ADS 3483, the probable quadruple Zeta Sge, the red dwarfpair Kpr 99, and the stars 46 Tau, 73 Oph, and 81 Cnc. New mass ratioand parallax results are also given for six of the objects studied.Objects and elements, an ephemerides, and comparisons with observationsthat have for the most part been condensed into normal places, arepresented in tabular form.
| Micrometer Observations of Double Stars and New Pairs - Part Ten
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1980ApJS...44..111H&db_key=AST
| MK Classification of 142 Visual Binaries
Not Available
| Eléments orbitaux de neuf étoiles doubles visuelles
Not Available
| Double stars (Report on progress of astronomy)
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