תוכן
תמונות
הוסף תמונה שלך
DSS Images Other Images
מאמרים קשורים
A deep proper-motion survey of the nearby open cluster Blanco
We provide two comprehensive catalogues of positions and proper motionsin the area of open cluster Blanco 1. The main catalogue, CTLGM,contains 6271 objects down to V˜ 18.5 and covers a circular˜11 deg2 area. The accuracy of CTLGM proper motions, atabout 0.3-0.5 mas yr-1 for well-measured stars, permits anexcellent segregation between the cluster and field stars. Thevector-point diagram of proper motions indicates an estimated total of˜165 cluster members among the stars in our sample, while 314stars with ?? < 2.5 mas yr-1 havemembership probabilities P?? 1 per cent. We alsoexplored the astrometric potential of the Catalogue of Objects andMeasured Parameters from All Sky Surveys (COMPASS) data base in order toobtain additional proper motions for fainter stars in the area of Blanco1. This effort produced the second catalogue of proper motions, CTLGD,containing 11 598 objects down to V˜ 21. A total of 4273 objectsare common between the two catalogues. The accuracy of proper motions inCTLGD ranges from 1.0 to 6 mas yr-1. A combination of bothproper-motion catalogues was instrumental in confirming that Blanco 1contains a large population of M dwarfs (˜150 down to M5 V - thelimit of our survey). In many respects, Blanco 1 is a scaled down‘twin’ of the Pleiades. The noted discrepancy between thedistance from a new Hipparcos parallax of Blanco 1 and the cluster'sphotometric distance, at least partially, might be due to the apparentcorrelation between parallax and proper motion in right ascension forthe ensemble of cluster members.
| The PASTEL catalogue of stellar parameters
Aims: The PASTEL catalogue is an update of the [Fe/H] catalogue,published in 1997 and 2001. It is a bibliographical compilation ofstellar atmospheric parameters providing (T_eff, log g, [Fe/H])determinations obtained from the analysis of high resolution, highsignal-to-noise spectra, carried out with model atmospheres. PASTEL alsoprovides determinations of the one parameter T_eff based on variousmethods. It is aimed in the future to provide also homogenizedatmospheric parameters and elemental abundances, radial and rotationalvelocities. A web interface has been created to query the catalogue onelaborated criteria. PASTEL is also distributed through the CDS databaseand VizieR. Methods: To make it as complete as possible, the mainjournals have been surveyed, as well as the CDS database, to findrelevant publications. The catalogue is regularly updated with newdeterminations found in the literature. Results: As of Febuary2010, PASTEL includes 30151 determinations of either T_eff or (T_eff,log g, [Fe/H]) for 16 649 different stars corresponding to 865bibliographical references. Nearly 6000 stars have a determination ofthe three parameters (T_eff, log g, [Fe/H]) with a high qualityspectroscopic metallicity.The catalogue can be queried through a dedicated web interface at http://pastel.obs.u-bordeaux1.fr/.It is also available in electronic form at the Centre de DonnéesStellaires in Strasbourg (http://vizier.u-strasbg.fr/viz-bin/VizieR?-source=B/pastel),at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) orvia http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/515/A111
| Spectroscopic study of the open cluster Blanco 1
Aims: As a part of our program on binaries in open clusters, we presenta spectroscopic study of the bright stars of Blanco 1 aimed at detectingand characterizing spectroscopic binaries. Methods: Forty fivestars previously mentioned as cluster candidates, plus another 24 starsin a wider region around the cluster were observed repeatedly during 6years, with a spectral resolving power 13 300. Radial velocities weremeasured by cross-correlations. Results: We obtained a meancluster velocity of 6.2 ± 0.3 km s-1 and determinedkinematic membership. Eleven spectroscopic binaries were detected, andorbital solutions are presented for eight of them. Six binaries areconfirmed to be members of the cluster. All of them are single-linedspectroscopic systems with periods in the range 1.9-1380 days.Considering all suspected binaries, the cluster binary frequency amountsto about 50%.Based on observations obtained at the Complejo Astronómico ElLeoncito (CASLEO), Argentina.
| Membership, binarity, and rotation of F-G-K stars in the open cluster Blanco 1
Context: The nearby open cluster Blanco 1 is of considerableastrophysical interest for formation and evolution studies of openclusters because it is the third highest Galactic latitude clusterknown. It has been observed often, but so far no definitive andcomprehensive membership determination is readily available. Aims: An observing programme was carried out to study the stellarpopulation of Blanco 1, and especially the membership and binaryfrequency of the F5-K0 dwarfs. Methods: We obtainedradial-velocities with the CORAVEL spectrograph in the field of Blanco 1for a sample of 148 F-G-K candidate stars in the magnitude range 10
| Effective temperature scale and bolometric corrections from 2MASS photometry
We present a method to determine effective temperatures, angularsemi-diameters and bolometric corrections for population I and II FGKtype stars based on V and 2MASS IR photometry. Accurate calibration isaccomplished by using a sample of solar analogues, whose averagetemperature is assumed to be equal to the solar effective temperature of5777 K. By taking into account all possible sources of error we estimateassociated uncertainties to better than 1% in effective temperature andin the range 1.0-2.5% in angular semi-diameter for unreddened stars.Comparison of our new temperatures with other determinations extractedfrom the literature indicates, in general, remarkably good agreement.These results suggest that the effective temperaure scale of FGK starsis currently established with an accuracy better than 0.5%-1%. Theapplication of the method to a sample of 10 999 dwarfs in the Hipparcoscatalogue allows us to define temperature and bolometric correction (Kband) calibrations as a function of (V-K), [m/H] and log g. Bolometriccorrections in the V and K bands as a function of T_eff, [m/H] and log gare also given. We provide effective temperatures, angularsemi-diameters, radii and bolometric corrections in the V and K bandsfor the 10 999 FGK stars in our sample with the correspondinguncertainties.
| 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.
| Catalogue of [Fe/H] determinations for FGK stars: 2001 edition
The catalogue presented here is a compilation of published atmosphericparameters (Teff, log g, [Fe/H]) obtained from highresolution, high signal-to-noise spectroscopic observations. This newedition has changed compared to the five previous versions. It is nowrestricted to intermediate and low mass stars (F, G and K stars). Itcontains 6354 determinations of (Teff, log g, [Fe/H]) for3356 stars, including 909 stars in 79 stellar systems. The literature iscomplete between January 1980 and December 2000 and includes 378references. The catalogue is made up of two tables, one for field starsand one for stars in galactic associations, open and globular clustersand external galaxies. The catalogue is distributed through the CDSdatabase. Access to the catalogue with cross-identification to othersets of data is also possible with VizieR (Ochsenbein et al.\cite{och00}). The catalogue (Tables 1 and 2) is only available inelectronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr(130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/373/159 and VizieRhttp://vizier.u-strasbg.fr/.
| Absolute proper motions of open clusters. I. Observational data
Mean proper motions and parallaxes of 205 open clusters were determinedfrom their member stars found in the Hipparcos Catalogue. 360 clusterswere searched for possible members, excluding nearby clusters withdistances D < 200 pc. Members were selected using ground basedinformation (photometry, radial velocity, proper motion, distance fromthe cluster centre) and information provided by Hipparcos (propermotion, parallax). Altogether 630 certain and 100 possible members werefound. A comparison of the Hipparcos parallaxes with photometricdistances of open clusters shows good agreement. The Hipparcos dataconfirm or reject the membership of several Cepheids in the studiedclusters. Tables 1 and 2 are only available in electronic form at theCDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/Abstract.html
| Open clusters with Hipparcos. I. Mean astrometric parameters
New memberships, mean parallaxes and proper motions of all 9 openclusters closer than 300 pc (except the Hyades) and 9rich clusters between 300 and 500 pc have been computed using Hipparcosdata. Precisions, ranging from 0.2 to 0.5 mas for parallaxes and 0.1 to0.5 mas/yr for proper motions, are of great interest for calibratingphotometric parallaxes as well as for kinematical studies. Carefulinvestigations of possible biases have been performed and no evidence ofsignificant systematic errors on the mean cluster parallaxes has beenfound. The distances and proper motions of 32 more distant clusters,which may be used statistically, are also indicated. Based onobservations made with the ESA Hipparcos astrometry satellite
| A catalogue of [Fe/H] determinations: 1996 edition
A fifth Edition of the Catalogue of [Fe/H] determinations is presentedherewith. It contains 5946 determinations for 3247 stars, including 751stars in 84 associations, clusters or galaxies. The literature iscomplete up to December 1995. The 700 bibliographical referencescorrespond to [Fe/H] determinations obtained from high resolutionspectroscopic observations and detailed analyses, most of them carriedout with the help of model-atmospheres. The Catalogue is made up ofthree formatted files: File 1: field stars, File 2: stars in galacticassociations and clusters, and stars in SMC, LMC, M33, File 3: numberedlist of bibliographical references The three files are only available inelectronic form at the Centre de Donnees Stellaires in Strasbourg, viaanonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5), or viahttp://cdsweb.u-strasbg.fr/Abstract.html
| Abundance analysis and origin of the ζ SCULPTORIS open cluster.
We have determined chemical abundances and radial velocities for starsin the field of the ζ Sculptoris cluster. We find that the clustermetal deficiency previously found from UBV photometry is not supported;the cluster overall metallicity, [Fe/H]=+0.23, is about 70% higher thanthe solar value. The chemical abundance pattern appears unusual: theNi/Fe ratio is lower than typical for field stars with similar Fe and Caabundances, and the cluster may also be deficient in the α elementSi. For its age, the cluster is unusually far from the galactic disk,=~240pc. The adopted heliocentric cluster radial velocity, +3.9km/s,shows that it is close to its maximum distance from the galactic plane.We suggest that the ζSculptoris cluster was formed in the galacticdisk 45Myr ago by the interaction of a high velocity cloud with theinterstellar medium, and that its formation may be connected with thatof Gould's Belt.
| UBV and uvby-beta photometry of stars in the region of the Zeta SCULPTORIS cluster
Photoelectric observations of 130 stars in the region of Zeta Sculptorishave been obtained in UBV and uvby-beta. A total of 32 stars areidentified as cluster members, and several other F and G type stars areidentified as probable members. Results indicate an interstellarreddening of E(B-V) = 0.02 mag and that the cluster is slightly metaldeficient.
|
הכנס מאמר חדש
לינקים קשורים
הכנס לינק חדש
משמש של הקבוצה הבאה
|
תצפית ומידע אסטרומטרי
| קבוצת-כוכבים: | פסל |
| התרוממות ימנית: | 00h02m39.24s |
| סירוב: | -29°04'30.9" |
| גודל גלוי: | 10.26 |
| תנועה נכונה: | 18.5 |
| תנועה נכונה: | 1 |
| B-T magnitude: | 10.658 |
| V-T magnitude: | 10.293 |
קטלוגים וכינוים:
|
