Contents
Images
Upload your image
DSS Images Other Images
Related articles
The RAdial Velocity Experiment (RAVE): Third Data Release
We present the third data release of the RAdial Velocity Experiment(RAVE) which is the first milestone of the RAVE project, releasing thefull pilot survey. The catalog contains 83,072 radial velocitymeasurements for 77,461 stars in the southern celestial hemisphere, aswell as stellar parameters for 39,833 stars. This paper describes thecontent of the new release, the new processing pipeline, as well as anupdated calibration for the metallicity based upon the observation ofadditional standard stars. Spectra will be made available in a futurerelease. The data release can be accessed via the RAVE Web site.
| Distance determination for RAVE stars using stellar models . II. Most likely values assuming a standard stellar evolution scenario
The RAdial Velocity Experiment (RAVE) is a spectroscopic survey of theMilky Way which already collected over 400 000 spectra of ~ 330 000different stars. We use the subsample of spectra with spectroscopicallydetermined values of stellar parameters to determine the distances tothese stars. The list currently contains 235 064 high quality spectrawhich show no peculiarities and belong to 210 872 different stars. Thenumbers will grow as the RAVE survey progresses. The public version ofthe catalog will be made available through the CDS services along withthe ongoing RAVE public data releases. The distances are determined witha method based on the work by Breddels et al. (2010, A&A, 511, A16).Here we assume that the star undergoes a standard stellar evolution andthat its spectrum shows no peculiarities. The refinements include: theuse of either of the three isochrone sets, a better account of thestellar ages and masses, use of more realistic errors of stellarparameter values, and application to a larger dataset. The deriveddistances of both dwarfs and giants match within ~ 21% to theastrometric distances of Hipparcos stars and to the distances ofobserved members of open and globular clusters. Multiple observations ofa fraction of RAVE stars show that repeatability of the deriveddistances is even better, with half of the objects showing a distancescatter of ? 11%. RAVE dwarfs are ~ 300 pc from the Sun, and giantsare at distances of 1 to 2 kpc, and up to 10 kpc. This places the RAVEdataset between the more local Geneva-Copenhagen survey and the moredistant and fainter SDSS sample. As such it is ideal to address some ofthe fundamental questions of Galactic structure and evolution in thepre-Gaia era. Individual applications are left to separate papers, herewe show that the full 6-dimensional information on position and velocityis accurate enough to discuss the vertical structure and kinematicproperties of the thin and thick disks.The catalog is only available in electronic form at the CDS viaanonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/522/A54
| Proper-motion binaries in the Hipparcos catalogue. Comparison with radial velocity data
Context: .This paper is the last in a series devoted to the analysis ofthe binary content of the Hipparcos Catalogue. Aims: .Thecomparison of the proper motions constructed from positions spanning ashort (Hipparcos) or long time (Tycho-2) makes it possible to uncoverbinaries with periods of the order of or somewhat larger than the shorttime span (in this case, the 3 yr duration of the Hipparcos mission),since the unrecognised orbital motion will then add to the propermotion. Methods: .A list of candidate proper motion binaries isconstructed from a carefully designed χ2 test evaluatingthe statistical significance of the difference between the Tycho-2 andHipparcos proper motions for 103 134 stars in common between the twocatalogues (excluding components of visual systems). Since similar listsof proper-motion binaries have already been constructed, the presentpaper focuses on the evaluation of the detection efficiency ofproper-motion binaries, using different kinds of control data (mostlyradial velocities). The detection rate for entries from the NinthCatalogue of Spectroscopic Binary Orbits (S_B^9) is evaluated, as wellas for stars like barium stars, which are known to be all binaries, andfinally for spectroscopic binaries identified from radial velocity datain the Geneva-Copenhagen survey of F and G dwarfs in the solarneighbourhood. Results: .Proper motion binaries are efficientlydetected for systems with parallaxes in excess of ~20 mas, and periodsin the range 1000-30 000 d. The shortest periods in this range(1000-2000 d, i.e., once to twice the duration of the Hipparcos mission)may appear only as DMSA/G binaries (accelerated proper motion in theHipparcos Double and Multiple System Annex). Proper motion binariesdetected among S_B9 systems having periods shorter than about400 d hint at triple systems, the proper-motion binary involving acomponent with a longer orbital period. A list of 19 candidate triplesystems is provided. Binaries suspected of having low-mass(brown-dwarf-like) companions are listed as well. Among the 37 bariumstars with parallaxes larger than 5 mas, only 7 exhibit no evidence forduplicity whatsoever (be it spectroscopic or astrometric). Finally, thefraction of proper-motion binaries shows no significant variation amongthe various (regular) spectral classes, when due account is taken forthe detection biases.Full Table [see full textsee full text] is only available in electronicform at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5)or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/464/377
| Statistical Constraints for Astrometric Binaries with Nonlinear Motion
Useful constraints on the orbits and mass ratios of astrometric binariesin the Hipparcos catalog are derived from the measured proper motiondifferences of Hipparcos and Tycho-2 (Δμ), accelerations ofproper motions (μ˙), and second derivatives of proper motions(μ̈). It is shown how, in some cases, statistical bounds can beestimated for the masses of the secondary components. Two catalogs ofastrometric binaries are generated, one of binaries with significantproper motion differences and the other of binaries with significantaccelerations of their proper motions. Mathematical relations betweenthe astrometric observables Δμ, μ˙, and μ̈ andthe orbital elements are derived in the appendices. We find a remarkabledifference between the distribution of spectral types of stars withlarge accelerations but small proper motion differences and that ofstars with large proper motion differences but insignificantaccelerations. The spectral type distribution for the former sample ofbinaries is the same as the general distribution of all stars in theHipparcos catalog, whereas the latter sample is clearly dominated bysolar-type stars, with an obvious dearth of blue stars. We point outthat the latter set includes mostly binaries with long periods (longerthan about 6 yr).
|
Submit a new article
Related links
Submit a new link
Member of following groups:
|
Observation and Astrometry data
| Constellation: | Hydre mâle |
| Right ascension: | 02h59m26.88s |
| Declination: | -72°30'17.0" |
| Apparent magnitude: | 10.918 |
| Proper motion RA: | -2.2 |
| Proper motion Dec: | 22.9 |
| B-T magnitude: | 11.651 |
| V-T magnitude: | 10.979 |
Catalogs and designations:
|
