Contenuti
Immagini
Carica la tua immagine
DSS Images Other Images
Articoli relazionati
A radial velocity survey of low Galactic latitude structures - I. Kinematics of the Canis Major dwarf galaxy
As part of a radial velocity survey of low Galactic latitude structuresthat we undertook with the 2dF spectrograph on the Anglo-AustralianTelescope, we present the radial velocities of more than 1500 red giantbranch and red clump stars towards the centre of the Canis Major dwarfgalaxy. With a mean velocity of 72 +/- 7kms-1 at aheliocentric distance of 5.5kpc and 114 +/- 2kms-1 at 8.5kpc,these stars present a peculiar distance - radial velocity relation thatis unlike that expected from thin or thick disc stars. Moreover, theybelong to a kinematically cold population with an intrinsic dispersionthat may be as low as 11+3-1kms-1. Acomparison of the velocity distribution obtained in this work withprevious studies shows the importance of using our new reductionpipeline and averaging the velocities obtained from different templates.The radial velocity distribution is used to select Canis Major stars inthe UCAC2.0 proper motion catalogue and derive proper motions inGalactic coordinates of (μl, μb) = (-3.6 +/-0.8masyr-1, 1.5 +/- 0.4masyr-1) for the dwarfgalaxy, which after correcting for the reflex solar motion along thisline of sight gives (μ'l, μ'b) = (-6.8 +/-0.8masyr-1, 0.8 +/- 0.4masyr-1), corresponding toa prograde orbit with a tangential velocity of ~235kms-1 atthe average distance of ~7.2kpc. All these kinematic constraints can bereproduced in simulations of the accretion of a dwarf on to the Galacticdisc. Such a process could also be responsible for the Monoceros Ringthat has recently been shown to encompass the Galactic disc. However,without constraints on the kinematics of the tidal arms emerging fromthe Canis Major dwarf, it is not yet possible to definitively prove alink between the two structures.
| Sixth Catalogue of Fundamental Stars (FK6). Part III. Additional fundamental stars with direct solutions
The FK6 is a suitable combination of the results of the HIPPARCOSastrometry satellite with ground-based data, measured over a longinterval of time and summarized mainly in the FK5. Part III of the FK6(abbreviated FK6(III)) contains additional fundamental stars with directsolutions. Such direct solutions are appropriate for single stars or forobjects which can be treated like single stars. Part III of the FK6contains in total 3272 stars. Their ground-based data stem from thebright extension of the FK5 (735 stars), from the catalogue of remainingSup stars (RSup, 732 stars), and from the faint extension of the FK5(1805 stars). From the 3272 stars in Part III, we have selected 1928objects as "astrometrically excellent stars", since their instantaneousproper motions and their mean (time-averaged) ones do not differsignificantly. Hence most of the astrometrically excellent stars arewell-behaving "single-star candidates" with good astrometric data. Thesestars are most suited for high-precision astrometry. On the other hand,354 of the stars in Part III are Δμ binaries in the sense ofWielen et al. (1999). Many of them are newly discovered probablebinaries with no other hitherto known indication of binarity. The FK6gives, besides the classical "single-star mode" solutions (SI mode),other solutions which take into account the fact that hidden astrometricbinaries among "apparently single-stars" introduce sizable "cosmicerrors" into the quasi-instantaneously measured HIPPARCOS proper motionsand positions. The FK6 gives, in addition to the SI mode, the "long-termprediction (LTP) mode" and the "short-term prediction (STP) mode". TheseLTP and STP modes are on average the most precise solutions forapparently single stars, depending on the epoch difference with respectto the HIPPARCOS epoch of about 1991. The typical mean error of anFK6(III) proper motion in the single-star mode is 0.59 mas/year. This isa factor of 1.34 better than the typical HIPPARCOS errors for thesestars of 0.79 mas/year. In the long-term prediction mode, in whichcosmic errors are taken into account, the FK6(III) proper motions have atypical mean error of 0.93 mas/year, which is by a factor of about 2better than the corresponding error for the HIPPARCOS values of 1.83mas/year (cosmic errors included).
| Classification and Identification of IRAS Sources with Low-Resolution Spectra
IRAS low-resolution spectra were extracted for 11,224 IRAS sources.These spectra were classified into astrophysical classes, based on thepresence of emission and absorption features and on the shape of thecontinuum. Counterparts of these IRAS sources in existing optical andinfrared catalogs are identified, and their optical spectral types arelisted if they are known. The correlations between thephotospheric/optical and circumstellar/infrared classification arediscussed.
| Vitesses radiales. Catalogue WEB: Wilson Evans Batten. Subtittle: Radial velocities: The Wilson-Evans-Batten catalogue.
We give a common version of the two catalogues of Mean Radial Velocitiesby Wilson (1963) and Evans (1978) to which we have added the catalogueof spectroscopic binary systems (Batten et al. 1989). For each star,when possible, we give: 1) an acronym to enter SIMBAD (Set ofIdentifications Measurements and Bibliography for Astronomical Data) ofthe CDS (Centre de Donnees Astronomiques de Strasbourg). 2) the numberHIC of the HIPPARCOS catalogue (Turon 1992). 3) the CCDM number(Catalogue des Composantes des etoiles Doubles et Multiples) byDommanget & Nys (1994). For the cluster stars, a precise study hasbeen done, on the identificator numbers. Numerous remarks point out theproblems we have had to deal with.
| Fifth fundamental catalogue. Part 2: The FK5 extension - new fundamental stars
The mean positions and proper motions for 3117 new fundamental starsessentially in the magnitude range about 4.5 to 9.5 are given in thisFK5 extension. Mean apparent visual magnitude is 7.2 and is on average2.5 magnitudes fainter then the basic FK5 which has a mean magnitude of4.7. (The basic FK5 gives the mean positions and proper motions for theclassical 1535 fundamental stars). The following are discussed: theobservational material, reduction of observations, star selection, andthe system for the FK5 extension. An explanation and description of thecatalog are given. The catalog of 3117 fundamental stars for the equinoxand epoch J2000.0 and B1950.0 is presented. The parallaxes and radialvelocities for 22 extension stars with large forecasting effects aregiven. Catalogs used in the compilation of the FK5 fundamental catalogare listed.
| First Stellar Catalog in Rio-Grande
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1985RMxAA..10..377M&db_key=AST
| Résultats des observations faites à Tananarive avec l'Astrolabe A. Danjon
Not Available
|
Sottometti un nuovo articolo
Link relazionati
Sottometti un nuovo link
Membro dei seguenti gruppi:
|
Osservazione e dati astrometrici
| Costellazione: | Vele |
| Ascensione retta: | 10h20m16.70s |
| Declinazione: | -47°41'57.0" |
| Magnitudine apparente: | 5.65 |
| Distanza: | 826.446 parsec |
| Moto proprio RA: | -9.1 |
| Moto proprio Dec: | 3.8 |
| B-T magnitude: | 7.85 |
| V-T magnitude: | 5.824 |
Cataloghi e designazioni:
|
NEWS@SKY (Science&Space News)
