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
| Distance determination for RAVE stars using stellar models
Aims: We develop a method for deriving distances fromspectroscopic data and obtaining full 6D phase-space coordinates for theRAVE survey's second data release. Methods: We used stellarmodels combined with atmospheric properties from RAVE (effectivetemperature, surface gravity and metallicity) and (J-Ks)photometry from archival sources to derive absolute magnitudes. Incombination with apparent magnitudes, sky coordinates, proper motionsfrom a variety of sources and radial velocities from RAVE, we are ableto derive the full 6D phase-space coordinates for a large sample of RAVEstars. This method is tested with artificial data, Hipparcostrigonometric parallaxes and observations of the open cluster M 67. Results: When we applied our method to a set of 16 146 stars, wefound that 25% (4037) of the stars have relative (statistical) distanceerrors of <35%, while 50% (8073) and 75% (12 110) have relative(statistical) errors smaller than 45% and 50%, respectively. Our varioustests show that we can reliably estimate distances for main-sequencestars, but there is an indication of potential systematic problems withgiant stars owing to uncertainties in the underlying stellar models. Forthe main-sequence star sample (defined as those with log(g) > 4), 25%(1744) have relative distance errors <31%, while 50% (3488) and 75%(5231) have relative errors smaller than 36% and 42%, respectively. Ourfull dataset shows the expected decrease in the metallicity of stars asa function of distance from the Galactic plane. The known kinematicsubstructures in the U and V velocity components of nearby dwarf starsare apparent in our dataset, confirming the accuracy of our data and thereliability of our technique. We provide independent measurements of theorientation of the UV velocity ellipsoid and of the solar motion, andthey are in very good agreement with previous work. Conclusions:The distance catalogue for the RAVE second data release is available athttp://www.astro.rug.nl/~rave,and will be updated in the future to include new data releases.
| The Properties of Long-Period Variables in the Large Magellanic Cloud from MACHO
We present a new analysis of the long-period variables in the LargeMagellanic Cloud (LMC) from the MACHO Variable Star Catalog.Three-quarters of our sample of evolved, variable stars have periodiclight curves. We characterize the stars in our sample using the multipleperiods found in their frequency spectra. Additionally, we usesingle-epoch Two Micron All Sky Survey measurements to construct theaverage infrared light curves for different groups of these stars.Comparison with evolutionary models shows that stars on the red giantbranch (RGB) or the early asymptotic giant branch (AGB) often shownon-periodic variability, but begin to pulsate with periods on the twoshortest period-luminosity (P-L) sequences (3 & 4) when theybrighten to K s ? 13. The stars on the thermally pulsingAGB are more likely to pulsate with longer periods that lie on the nexttwo P-L sequences (1 & 2), including the sequence associated withthe Miras in the LMC. The Petersen diagram and its variants show thatmulti-periodic stars on each pair of these sequences (3 & 4, and 1& 2) typically pulsate with periods associated only with that pair.The periods in these multi-periodic stars become longer and stronger asthe star evolves. We further constrain the mechanism behind the longsecondary periods (LSPs) seen in half of our sample, and find that thereis a close match between the luminosity functions of the LSP stars andall of the stars in our sample, and that these star's pulsationamplitudes are relatively wavelength independent. Although this ischaracteristic of stellar multiplicity, the large number of thesevariables is problematic for that explanation.
| Pulkovo compilation of radial velocities for 35495 stars in a common system.
Not Available
| 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.
| Ca II H and K Filter Photometry on the UVBY System. II. The Catalog of Observations
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1995AJ....109.2828T&db_key=AST
| Ubvy-beta photometry of high-velocity and metal-poor stars. III - Metallicities and ages of the halo stars
The interstellar color excesses, E(b-y) and the metallicities, Fe/Habundance ratio, are determined for the 711 high-velocity and metal-poorstars in the catalog of ubvy-beta photometry compiled by Schuster andNissen (1988). It is found that 220 of these are halo stars and that 15percent of these halo stars have colors that are significantly affectedby interstellar reddening. A minimum age of 18-20 Gyr is determined forthe halo stars. The results suggest that a pressure-supported slowuniform collapse controlled the formation and evolution of the Galaxy.
| Four-color UVBY and H-beta photometry of high-velocity and metal-poor stars. I - The catalogue of observations
A catalog of four-color uvby and H-beta photometry for 711 high-velocityand metal-poor stars is given. The selection of the stars and theobserving and reduction techniques used to obtain these data arediscussed. The photometry has been transformed closely onto the standarduvby-beta system. The errors of the data have been estimated using bothinternal and external comparisons. The data are uniform over the sky;that is, there are no significant north-south differences. For the largemajority of stars the mean errors of V, m1, c1, and beta are less than +or - 0.008 mag, and the error of b-y is less than + or - 0.005 mag.Values of V, b-y and beta and rough photometric classifications aregiven for 63 red and/or evolved stars that fall outside the range of thephotometric transformations.
| Starlight polarization in the Magellanic cloud regions.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1976A&AS...24..357S&db_key=AST
| Interstellar reddening in the Large Magellanic Cloud
Interstellar reddening is determined for each of 702 supergiants in theLarge Magellanic Cloud from a two-color diagram for early-type stars andthe intrinsic colors of intermediate and late-type stars. A considerableamount of interstellar reddening is indicated by the scatter in thediagram, and the space distribution of the brightest stars is shown tobe similar to that of the most reddened stars. The distribution ofinterstellar dust is found to be dominated by the 30 Doradusassociation, and it is suggested that the entire association may beembedded in a huge dust-cloud complex. Stars with a high degree ofreddening are shown to be strongly concentrated in regions of enhancedneutral-hydrogen density. Stars having color excesses of at least 0.30 mare discussed individually.
| Non-supergiant high-velocity stars near the Magellanic Clouds.
Abstract image available at:http://adsabs.harvard.edu/abs/1974A&AS...16..277C
| Additional observations of supergiants and foreground stars in the direction of the Large Magellanic Cloud
Abstract image available at:http://adsabs.harvard.edu/abs/1973A&AS....9..447B
| Remarks on the Comparison between the Sanduleak and the Febrenbach- Duflot Catalogs of LMC Member Stars
Abstract image available at:http://adsabs.harvard.edu/abs/1972A&A....21..321F
| Spectrographic and photometric observations of supergiants and foreground stars in the direction of the Large Magellanic Cloud
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1972A&AS....6..249A&db_key=AST
| Comparison of the Large Magellanic Cloud Catalogs of Sanduleak and Fehrenbach-Duflot
Abstract image available at:http://adsabs.harvard.edu/abs/1972A&A....17..326S
| 6-color photometry of 13 F-G supergiants in the Large Magellanic Cloud.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1971A&A....15..320B&db_key=AST
| Grand Nuage de Magellan. Liste des etoiles membres DU Grand Nuage de Magellan et liste d'etoiles galactiques
Not Available
|
Submit a new article
Related links
Submit a new link
Member of following groups:
|
Observation and Astrometry data
| Constellation: | Τράπεζα |
| Right ascension: | 05h12m29.88s |
| Declination: | -70°56'42.2" |
| Apparent magnitude: | 11.301 |
| Proper motion RA: | 148.4 |
| Proper motion Dec: | 40.3 |
| B-T magnitude: | 11.769 |
| V-T magnitude: | 11.34 |
Catalogs and designations:
|
