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Pulkovo compilation of radial velocities for 35495 stars in a common system.
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| Tertiary companions to close spectroscopic binaries
We have surveyed a sample of 165 solar-type spectroscopic binaries (SB)with periods from 1 to 30 days for higher-order multiplicity. Asubsample of 62 targets were observed with the NACO adaptive opticssystem and 13 new physical tertiary companions were detected. Anadditional 12 new wide companions (5 still tentative) were found usingthe 2MASS all-sky survey. The binaries belong to 161 stellar systems; ofthese 64 are triple, 11 quadruple and 7 quintuple. After correction forincompleteness, the fraction of SBs with additional companions is foundto be 63% ± 5%. We find that this fraction is a strong functionof the SB period P, reaching 96% for P<3d and dropping to34% for P>12^d. Period distributions of SBs with and withouttertiaries are significantly different, but their mass ratiodistributions are identical. The statistical data on the multiplicity ofclose SBs presented in this paper indicates that the periods and massratios of SBs were established very early, but the periods of SB systemswith triples were further shortened by angular momentum exchange withcompanions.
| Astrometric orbits of SB^9 stars
Hipparcos Intermediate Astrometric Data (IAD) have been used to deriveastrometric orbital elements for spectroscopic binaries from the newlyreleased Ninth Catalogue of Spectroscopic Binary Orbits(SB^9). This endeavour is justified by the fact that (i) theastrometric orbital motion is often difficult to detect without theprior knowledge of the spectroscopic orbital elements, and (ii) suchknowledge was not available at the time of the construction of theHipparcos Catalogue for the spectroscopic binaries which were recentlyadded to the SB^9 catalogue. Among the 1374 binaries fromSB^9 which have an HIP entry (excluding binaries with visualcompanions, or DMSA/C in the Double and Multiple Stars Annex), 282 havedetectable orbital astrometric motion (at the 5% significance level).Among those, only 70 have astrometric orbital elements that are reliablydetermined (according to specific statistical tests), and for the firsttime for 20 systems. This represents a 8.5% increase of the number ofastrometric systems with known orbital elements (The Double and MultipleSystems Annex contains 235 of those DMSA/O systems). The detection ofthe astrometric orbital motion when the Hipparcos IAD are supplementedby the spectroscopic orbital elements is close to 100% for binaries withonly one visible component, provided that the period is in the 50-1000 drange and the parallax is >5 mas. This result is an interestingtestbed to guide the choice of algorithms and statistical tests to beused in the search for astrometric binaries during the forthcoming ESAGaia mission. Finally, orbital inclinations provided by the presentanalysis have been used to derive several astrophysical quantities. Forinstance, 29 among the 70 systems with reliable astrometric orbitalelements involve main sequence stars for which the companion mass couldbe derived. Some interesting conclusions may be drawn from this new setof stellar masses, like the enigmatic nature of the companion to theHyades F dwarf HIP 20935. This system has a mass ratio of 0.98 but thecompanion remains elusive.
| 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.
| SB9: The ninth catalogue of spectroscopic binary orbits
The Ninth Catalogue of Spectroscopic Binary Orbits(http://sb9.astro.ulb.ac.be) continues the series of compilations ofspectroscopic orbits carried out over the past 35 years by Batten andcollaborators. As of 2004 May 1st, the new Catalogue holds orbits for2386 systems. Some essential differences between this catalogue and itspredecessors are outlined and three straightforward applications arepresented: (1) completeness assessment: period distribution of SB1s andSB2s; (2) shortest periods across the H-R diagram; (3)period-eccentricity relation.
| The Mass Ratio Distribution in Main-Sequence Spectroscopic Binaries Measured by Infrared Spectroscopy
We report infrared spectroscopic observations of a large well-definedsample of main-sequence, single-lined spectroscopic binaries to detectthe secondaries and derive the mass ratio distribution of short-periodbinaries. The sample consists of 51 Galactic disk spectroscopic binariesfound in the Carney and Latham high proper motion survey, with primarymasses in the range 0.6-0.85 Msolar. Our infraredobservations detect the secondaries in 32 systems, two of which havemass ratios, q=M2/M1, as low as ~0.20. Togetherwith 11 systems previously identified as double-lined binaries byvisible light spectroscopy, we have a complete sample of 62 binaries, ofwhich 43 are double lined. The mass ratio distribution is approximatelyconstant over the range q=1.0-0.3. The distribution appears to rise atlower q values, but the uncertainties are sufficiently large that wecannot rule out a distribution that remains constant. The massdistribution derived for the secondaries in our sample and that of theextrasolar planets apparently represent two distinct populations.
| On the Mass-Ratio Distribution of Spectroscopic Binaries
In this paper we derive the mass-ratio and secondary-mass distributionsof a large, well-defined, complete sample of 129 spectroscopic binarieswith periods between 1 and 2500 days. The binaries, whose orbits werepublished recently, were detected by a systematic radial-velocity surveyof a sample of more than 1400 large proper motion stars. Three featuresstand out in the mass-ratio distribution: a rise as the mass ratio goesdown to q~0.2, a sharp drop below q~0.2, and a smaller peak at q~0.8.Another way to characterize the results is to state that thedistribution includes two ``populations,'' one with a high asymmetricpeak at q~0.2 and another with a smaller peak at q~0.8, while theminimum between the two populations is centered at q~0.55. The size ofthe binary sample allows us to divide it into two subsamples and lookfor differences in the mass-ratio distributions of the two subsamples.We performed two different divisions: one into Galactic halo versus diskpopulations, and the other into high- and low-mass primary stars (aboveand below 0.67 Msolar). The former division yieldsdifferences with moderate statistical significance of 88%, while thelatter is more significant at a level of 97%. Our analysis suggests thatthe rise toward low mass ratios does not appear in the mass-ratiodistribution of the halo binaries. The other separation shows a broadpeak at mass ratio of q~0.8-1 for the subsample of binaries withlow-mass primaries but no corresponding peak in the subsample withhigh-mass primaries. We discuss our findings and their application totheories of binary formation.
| 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.
| A Survey of Proper-Motion Stars. XVI. Orbital Solutions for 171 Single-lined Spectroscopic Binaries
We report 25,563 radial velocity measurements for 1359 single-linedstars in the Carney-Latham sample of 1464 stars selected for high propermotion. For 171 of these, we present spectroscopic orbital solutions. Wefind no obvious difference between the binary characteristics in thehalo and the disk populations. The observed frequency is the same, andthe period distributions are consistent with the hypothesis that the twosets of binaries were drawn from the same parent population. Thissuggests that metallicity in general, and radiative opacities inparticular, have little influence over the fragmentation process thatleads to short-period binaries. All the binaries with periods shorterthan 10 days have nearly circular orbits, while the binaries withperiods longer than 20 days exhibit a wide range of eccentricities and amedian value of 0.37. For the metal-poor high-velocity halo binaries inour sample, the transition from circular to eccentric orbits appears tooccur at about 20 days, supporting the conclusion that tidalcircularization on the main sequence is important for the oldestbinaries in the Galaxy. Some of the results presented here usedobservations made with the Multiple Mirror Telescope, a joint facilityof the Smithsonian Institution and the University of Arizona.
| ROSAT all-sky survey observations of PopII field binaries: X-ray activity of old, metal-poor stellar coronae.
This study represents the first X-ray observations of an extended sampleof Pop II field binaries, aimed at investigating the properties of old,metal-poor stellar coronae. Analysing X-ray observations from the ROSATall-sky survey, we detected only 13 (out of 86) Pop II systems (15%detection rate). The X-ray luminosity function, taking into account bothdetections and upper limits, has its median at logL_x_<=28.1erg/s,indicating a low average X-ray luminosity, with a high-luminosity tailat logL_x_~29-31erg/s. The only extreme metal-poor system detected is HD89499. Thus, the detection rate of extreme Pop II systems is lower thanof intermediate Pop II, possibly indicating extreme Pop II to betypically less luminous. The X-ray luminosity is not very wellcorrelated with orbital period; long-period Pop II binaries may havehigh X-ray luminosities and, surprisingly, short-period systems are notper se strong X-ray emitters. For a subsample of emission-line Pop IIbinaries, i.e. the halo component analogs to the RS CVn binaries, themedian X-ray luminosity is at least one order of magnitude lower thanfor the RS CVns. The lower activity levels of the Pop II systems may becaused in part by the presence of fewer evolved stars in the sample andlower metallicity. The extremely old age of Pop II binaries may alsogive rise to the unexpectedly low X-ray luminosities of some systems(e.g., CD-481741, BD+53080).
| Eccentricity versus Mass for Low-Mass Secondaries and Planets
Spectroscopic orbits have been reported for six unseen companionsorbiting solar-type stars with minimum possible masses in the range0.5--10 Jupiter masses. The four least massive companions, around 51Peg, 47 UMa, 55 Cnc, and tau Boo, have nearly circular orbits, while thetwo most massive companions, around HD 114762 and 70 Vir, haveeccentricities of 0.35 and 0.40. We compare the orbital eccentricitiesof these six planet candidates with the eccentricities of the planets inthe solar system, of the three planets found around the pulsar PSRB1957+12, and of the low-mass secondaries in a subsample of thespectroscopic binaries from the Carney-Latham proper-motion survey. Thedistribution of eccentricities for the combined samples displays astriking pattern: the companions with masses smaller than about 5Jupiter masses have circular orbits, while the more massive companionshave eccentric orbits. We outline four possible scenarios that mighthave produced this pattern of eccentricity versus mass.
| A survey of proper motion stars. 12: an expanded sample
We report new photometry and radial velocities for almost 500 stars fromthe Lowell Proper Motion Catalog. We combine these results with ourprior sample and rederive stellar temperatures based on the photometry,reddening, metallicities (using chi squared matching of our 22,500 lowSignal to Noise (S/N) high resolution echelle spectra with a grid ofsynthetic spectra), distances, space motions, and Galactic orbitalparameters for 1269 (kinematics) and 1261 (metallicity) of the 1464stars in the complete survey. The frequency of spectroscopic binariesfor the metal-poor ((m/H) less than or equal to -1.2) stars with periodsshorter than 3000 days is at least 15%. The spectroscopic binaryfrequency for metal-rich stars ((m/H) greater than -0.5) appears to belower, about 9%, but this may be a selection effect. We also discussspecial classes of stars, including treatment of the double-linedspectroscopic binaries, and identification of subgiants. Four possiblenew members of the class of field blue stragglers are noted. We pointout the detection of three possible new white dwarfs, six broad-lined(binary) systems, and discuss briefly the three already knownnitrogen-rich halo dwarfs. The primary result of this paper will beavailable on CD-ROM, in the form of a much larger table.
| A survey of proper motion stars. XI - Orbits for the second 40 spectroscopic binaries
Orbital solutions and spectroscopic metallicities for a second set of 40spectroscopic binaries found in an extended version of the Carney andLatham survey of proper-motion stars are reported. To investigate thedistribution of orbital eccentricity versus period for a pure sample ofhalo binaries, only those systems more metal poor than m/H = -1.6 areselected. The transition between circular and eccentric orbits is foundto occur at a period of about 19 d. This supports the interpretationthat tidal circularization has been more important on the main sequencethan during the premain-sequence stage for the sample of old binaries inthe halo.
| UBV photometry of stars whose positions are accurately known. II
The present report on the UBV observations of stars with favorableastrometric history gives attention to stars of the BD zones lyingbetween 50 and 54 deg. These observations and their reductions wereperformed from August 1983 to August 1984, as described by Oja (1984).Results are presented as tables for both the standard stars and theprogram stars. Comparisons are conducted between the present Vmagnitudes and those of the NPZT (1982) and AGK3R (1978) catalogs.
| Spectral classification of high-proper-motion stars
Spectral types have been found for about 900 stars of high proper motioncontained in the Lowell Observatory Northern Hemisphere proper-motionstar survey using all blue-region objective prism plates. The spectralclassification criteria are given. About eighty stars of largetangential velocity have been classified using slit spectrograms takenwith a 36-in. reflector. A new calibration of Luyten's absolutemagnitude vs reduced proper motion relation is made, and its dependenceon spectral type is investigated.
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