Single-lined Spectroscopic Binary Star Candidates from a Combination of the RAVE and Gaia DR2 Surveys

The combination of the final version of the Radial Velocity Experiment (RAVE) spectroscopic survey data release 6 with radial velocities (RVs) and astrometry from Gaia DR2 allows us to identify and create a catalog of single-lined binary star candidates (SB1), their inferred orbital parameters, and to inspect possible double-lined binary stars (SB2). A probability function for the detection of RV variations is used for identifying SB1 candidates. The estimation of orbital parameters for main-sequence dwarfs is performed by matching the measured RVs with theoretical velocity curves sampling the orbital parameter space. The method is verified by studying a mock sample from the SB 9 catalog. Studying the boxiness and asymmetry of the spectral lines allows us to identify possible SB2 candidates, while matching their spectra to a synthetic library indicates probable properties of their components. From the RAVE catalog we select 37,664 stars with multiple RV measurements and identify 3838 stars as SB1 candidates. Joining Rave and Gaia DR2 yields 450,646 stars with RVs measured by both surveys and 27,716 of them turn out to be SB1 candidates, which is an increase by an order of magnitude over previous studies. For main-sequence dwarf candidates we calculate their most probable orbital parameters: orbital periods are not longer than a few years and primary components have masses similar to the solar mass. All our results are available in the electronic version.Funding for RAVE has been provided by: the Leibniz-Institut für Astrophysik Potsdam (AIP); the Australian Astronomical Observatory; the Australian National University; the Australian Research Council; the French National Research Agency; the German Research Foundation (SPP 1177 and SFB 881); the European Research Council (ERC-StG 240271 Galactica); the Istituto Nazionale di Astrofisica at Padova; The Johns Hopkins University; the National Science Foundation of the USA (AST-0908326); the W. M. Keck foundation; the Macquarie University; the Netherlands Research School for Astronomy; the Natural Sciences and Engineering Research Council of Canada; the Slovenian Research Agency (core funding No. P1-0188); the Swiss National Science Foundation; the Science & Technology Facilities Council of the UK; Opticon; Strasbourg Observatory; and the Universities of Basel, Groningen, Heidelberg and Sydney. T.Z. thanks the Research School of Astronomy & Astrophysics in Canberra for support through a Distinguished Visitor Fellowship

Single-lined Spectroscopic Binary Star Candidates from a Combination of the RAVE and Gaia DR2 Surveys

The combination of the final version of the Radial Velocity Experiment (RAVE) spectroscopic survey data release 6 with radial velocities (RVs) and astrometry from Gaia DR2 allows us to identify and create a catalog of single-lined binary star candidates (SB1), their inferred orbital parameters, and to inspect possible double-lined binary stars (SB2). A probability function for the detection of RV variations is used for identifying SB1 candidates. The estimation of orbital parameters for main-sequence dwarfs is performed by matching the measured RVs with theoretical velocity curves sampling the orbital parameter space. The method is verified by studying a mock sample from the SB 9 catalog. Studying the boxiness and asymmetry of the spectral lines allows us to identify possible SB2 candidates, while matching their spectra to a synthetic library indicates probable properties of their components. From the RAVE catalog we select 37,664 stars with multiple RV measurements and identify 3838 stars as SB1 candidates. Joining Rave and Gaia DR2 yields 450,646 stars with RVs measured by both surveys and 27,716 of them turn out to be SB1 candidates, which is an increase by an order of magnitude over previous studies. For main-sequence dwarf candidates we calculate their most probable orbital parameters: orbital periods are not longer than a few years and primary components have masses similar to the solar mass. All our results are available in the electronic version

The sixth data release of the Radial Velocity Experiment (RAVE). I. Survey description, spectra and radial velocities

The Radial Velocity Experiment (RAVE) is a magnitude-limited (9<I<12) spectroscopic survey of Galactic stars randomly selected in the southern hemisphere. The RAVE medium-resolution spectra (R~7500) cover the Ca-triplet region (8410-8795A). The 6th and final data release (DR6 or FDR) is based on 518387 observations of 451783 unique stars. RAVE observations were taken between 12 April 2003 and 4 April 2013. Here we present the genesis, setup and data reduction of RAVE as well as wavelength-calibrated and flux-normalized spectra and error spectra for all observations in RAVE DR6. Furthermore, we present derived spectral classification and radial velocities for the RAVE targets, complemented by cross matches with Gaia DR2 and other relevant catalogs. A comparison between internal error estimates, variances derived from stars with more than one observing epoch and a comparison with radial velocities of Gaia DR2 reveals consistently that 68% of the objects have a velocity accuracy better than 1.4 km/s, while 95% of the objects have radial velocities better than 4.0 km/s. Stellar atmospheric parameters, abundances and distances are presented in subsequent publication. The data can be accessed via the RAVE Web (http://rave-survey.org) or the Vizier database.Comment: 32 pages, 11 figures, accepted for publication to A

Študij populacije spektroskopskih dvojnih zvezd z enojnimi črtami v pregledu neba RAVE

In the 10 years of observations, textsc{Rave} survey obtained radial velocities (RV) of 451,788 stars. Most of the stars were observed only once, but in the final textsc{Rave} data release 6, 37,664 of them (8.3 %) are classified as normal single stars that have multiple RV measurements. These objects were selected for this study. A probability function for the detection of RV variations is used for identifying 3838 single lined binary (SB1) candidates. From the 3838 SB1, 406 main sequence dwarf candidates with Solar like masses are selected and the estimation of orbital parameters (period, eccentricity, mass ratio and system velocity) is performed by matching the measured RVs with theoretical velocity curves sampling the orbital parameter space. The reliability of this method is verified by studying a mock sample from the The Ninth Catalogue of Spectroscopic Binary Orbits. Stars from this study were originally classified as normal single stars. Studying the boxiness and asymmetry of their calcium triplet spectral lines points out some possible SB2 candidates. Matching their spectra to a synthetic library indicates probable properties of their components. Joining textsc{Rave} and textit{Gaia} DR2 yields 450,646 stars with RVs measured by both surveys. Although textit{Gaia} published only median values of measured RVs, and stars with variable RVs were excluded from DR2, it turns out that 27,716 of them are SB1 candidates. This is an increase by an order of magnitude over study performed with the textsc{Rave} DR6 data only. It is obvious that larger time span between these two surveys will in the future enable detection of even more binaries, especially those with longer orbital periods. The study of SB1 from joined textsc{Rave} and textit{Gaia} surveys is of a great importance for the interpretation of the textit{Gaia} ongoing measurements, which will be published in the textit{Gaia} DR3, 1 year from now.V desetih letih opazovanj je pregled neba textsc{Rave} pridobil vrednosti radialnih hitrosti 451,788 zvezd. Vev{c}ina zvezd je bila opazovana le enkrat, vendar zadnja, konv{c}na objava podatkov vsebuje 37,664 zvezd (8.3 %), ki so oznav{c}ene kot obiv{c}ajne enojne zvezde, ter imajo vev{c} kot eno meritev radialne hitrosti. V tem delu smo preverili, ali morebitna spremenljivost radialne hitrosti vev{c}krat opazovanih zvezd kav{z}e na to, da ima zvezda nevidno gravitacijsko vezano spremljevalko. Z uporabo verjetnostne funkcije za zaznavanje spreminjajov{c}e radialne hitrosti smo identificirali 3838 takih dvojnih zvezd. Med 3838 zvezdami je 406 pripadnic glavne veje, z masami podobnimi masi Sonca. Te zvezde so bile izbrane za oceno orbitalnih parametrov kot so perioda, ekscentriv{c}nost tirnice, razmerje mas in sistemska hitrost. Izmerjene vrednosti radialne hitrosti posamezne zvezde so primerjane s teoretiv{c}nimi, za razliv{c}ne vrednosti parametrov, ki dolov{c}ajo obliko krivulje spremembe radialne hitrosti. Zanesljivost metode je preverjena na testnem vzorcu zvezd, z znanimi orbitalnimi parametri iz kataloga spektroskopskih dvojnic. v{C}eprav so zvezde iz te v{s}tudije bile prvotno razvrv{sc}ene med obiv{c}ajne enojne zvezde, je podrobna v{s}tudija v{c}okatosti in asimetrij v profilih spektralnih v{c}rt kalcijevega tripleta v nekaj primerih nakazala prispevek svetlobe spremljevalke. Pribliv{z}ek vrednosti fizikalnih parametrov obeh komponent je pridobljen s primerjavo spektra s teoretiv{c}nimi sintetiv{c}nimi spektri. Najdene dvojnice z dvojnimi spektralnimi v{c}rtami (SB2) imajo krajv{s}e orbitalne periode, velikostnega reda nekaj tednov ali mesecev, ter vev{c}je razlike radialnih hitrosti, ob tem pa podobne mase, kar pomeni podoben izsev, zaradi v{c}esa lahko opazimo vpliv sekundarne komponente v spektru. Skupni katalog pregleda neba textsc{Rave} in textit{Gaia} vsebuje 450,646 zvezd z vrednostimi radialnih hitrosti izmerjenih v obeh raziskavah. v{C}eprav je textit{Gaia} do sedaj objavila samo povprev{c}ne vrednosti radialnih hitrosti in so zvezde s spremenljivimi vrednostmi bile izkljuv{c}ene iz objave podatkov, se je izkazalo, da je med njimi 27,716 kandidatov za dvojnice. Ta v{s}tevilka je za velikostni red vev{c}ja od v{s}tevila dvojnic odkritih le v okviru projekta textsc{Rave} ali kateregakoli drugega spektroskopskega pregleda neba doslej