Садржај
Слике
Уплоадјуј своје слике
DSS Images Other Images
Везани чланци
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
| 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
| NGC 2287 - an important intermediate-age open cluster
We have obtained photoelectric UBV photometry for 100 stars, uvby-betaphotometry for 39 stars, and MK spectral types for 80 stars in the fieldof NGC 2287. After combination with data from other sources, severalinteresting cluster properties are apparent. Both the UBV and uvby-betaphotometry point to a small but nonzero reddening, while our spectraltypes confirm previous results indicating a high binary frequency forthe cluster. Based on our spectral and photometric data for the clustermembers with M(V) of between -1 and 3, we find a minimum binaryfrequency of 40 percent and discuss the possibility that the results mayimply a binary frequency closer to 80 percent. The cluster age is foundto be about 2 x 10 exp 8 yr based on both the main-sequence turnoff andthe red giant distribution; the width of the turnup region can probablybe explained by a combination of duplicity and a range in stellarrotation.
| Photometry of F-K type bright giants and supergiants. I - Intermediate band and H-Beta observations
Over 1500 observations of 560 bright giants and supergiants of types F-Kare presented and compared to the observations by Gray and Olsen (1991).The present results include intermediate-band which is slightlydifferent from the Stromgren data by Gray and Olsen due to a differentwidth for the v filter. A systematic difference in m(1) - M(1) withdecreasing temperature is noted in the two H-Beta data sets, and thecorrelations are defined.
| A catalogue of Fe/H determinations - 1991 edition
A revised version of the catalog of Fe/H determinations published by G.Cayrel et al. (1985) is presented. The catalog contains 3252 Fe/Hdeterminations for 1676 stars. The literature is complete up to December1990. The catalog includes only Fe/H determinations obtained from highresolution spectroscopic observations based on detailed spectroscopicanalyses, most of them carried out with model atmospheres. The catalogcontains a good number of Fe/H determinations for stars from open andglobular clusters and for some supergiants in the Magellanic Clouds.
| More radial-velocity measurements in young open clusters
Further high resolution radial-velocity measurements are reported in 23young open clusters using the Kitt Peak CCD coude spectrograph on the0.9-m feed telescope. The radial velocities for the cluster stars arederived with the technique of cross correlation. The internal precisionof the velocity measurements is typically 2 km/s for early type stars.From these new data and previously published velocities, the observedstars in two clusters, NGC 663 and NGC 2287, were found to show arelatively small dispersion in the measured mean velocities. Furtherobservations of stars in young clusters will be useful in helping toestablish an early-type-star-velocity standard system.
| First giant branch and asymptotic giant branch stars in nearby aggregates
The properties of the brightest red stars in several aggregates in theGalaxy are compared with theoretical models. 22 asymptotic giant branch(AGB) stars are identified, four of which are in the thermally pulsingAGB (TPAGB) phase and four of which are TPAGB carbon stars. Also, fourcases of RGB stars are identified which have accreted substantial massfrom the carbon-rich TPAGB precursor of a current white dwarf companion.There is general agreement between the observed and theoretical slopesof the RGB and early AGB branches, and quantitative differences betweenthe positioning of observed sequences can be understood in terms ofdifferences in metallicity and mass predicted by the theory.
| The Perkins catalog of revised MK types for the cooler stars
A catalog is presented listing the spectral types of the G, K, M, and Sstars that have been classified at the Perkins Observatory in therevised MK system. Extensive comparisons have been made to ensureconsistency between the MK spectral types of stars in the Northern andSouthern Hemispheres. Different classification spectrograms have beengradually improved in spite of some inherent limitations. In thecatalog, the full subclasses used are the following: G0, G5, G8, K0, K1,K2, K3, K4, K5, M0, M1, M2, M3, M4, M5, M6, M7, and M8. Theirregularities are the price paid for keeping the general scheme of theoriginal Henry Draper classification.
| Carbon isotope ratios and lithium abundances in open cluster giants
New high-resolution, high S/N spectra of CN lines at 8000 A and Li linesat 6707 A have been obtained for giants in about 20 Galactic openclusters and C-12/C-13 ratios and Li abundances determined for thesestars. The ages of the clusters vary from about 50 million years to 5billion years, and their turn-off masses vary from 1 solar mass to about6 solar masses. The ages and turn-off masses were determined by fittingtheoretical isochrones to the cluster color-magnitude diagrams.Correlation of the isotope ratio and the Li abundances with the clusterturn-off masses indicates the following: (1) the C-12/C-13 ratioincreases steeply with the turn-off mass until a mass of approximately2.2 solar masses when the ratio levels off abruptly to a value near 26;(2) older clusters with turn-off masses lower than about 2.2 solarmasses in general exhibit C-12/C-13 ratios that are considerably lowerthan the theoretically predicted values while those with larger turn-offmasses show ratios close to standard predictions; and (3) no strongcorrelation exists between the Li abundances and the cluster turn-offmass, and the Li abundances in giants are, in general, lower thantheoretically predicted values. Various theories to explain the observedabundance trends are discussed.
| Age determination of the open cluster NGC 2287 (M41)
Two different methods which take into account the rotation of the memberstars are used to determine the cluster age of NGC 2287 (M41). Thetheoretical Hertzsprung-Russell diagram is first obtained from theobserved color-magnitude diagram. The method based on the turn-off pointon the cluster Main Sequence yields an age of 3.10 x 10 to the 7th yr.By fitting the evolutionary tracks of rotating stars to the clusterHertzsprung-Russell diagram, an age of about 8.00 x 10 to the 7th yr isobtained.
| Radial velocities in the direction of the cluster NGC 2287
Mean radial velocities for 72 stars in the direction of NGC 2287 havebeen determined based on 10 plates obtained with the 40-cm ObjectivePrism of the La Silla ESO. The radial velocities are given in the IAUsystem with an accuracy of + or - 5 km/s. It is found that the peculiarstar HD 49022 is variable and has an amplitude of 70 km/s. The generalvelocity diagram has a maximum at about 22 km/s which may represent amixture of cluster and field stars and an asymmetry at 30 km/s which maybe attributed to binary member stars.
| On the Constancy of Some Stars in NGC 2287 = Messier 41
Not Available
| Yellow evolved stars in open clusters
This paper describes a program in which Galactic cluster post-AGBcandidates were first identified and then analyzed for clustermembership via radial velocities, monitored for possible photometricvariations, examined for evidence of mass loss, and classified ascompletely as possible in terms of their basic stellar parameters. Theintrinsically brightest supergiants are found in the youngest clusters.With increasing cluster age, the absolute luminosities attained by thesupergiants decline. It appears that the evolutionary tracks ofluminosity class II stars are more similar to those of class I than ofclass III. Only two superluminous giant star candidates are found inopen clusters.
| Membership in the open cluster NGC 2287
The open cluster NGC 2287 is a cluster apparently rich in multiple starsand several other spectroscopically interesting objects. The firstextended proper-motion membership survey of the cluster is reported. UBVphotometry of 146 proper-motion stars is also included and compared toearlier data. Color-magnitude and two-color diagrams are presented. Theproper-motion-based membership probabilities indicate that most of thespectroscopic binaries are members of the cluster, as are the threeHg-Mn stars, and at least four of the K giants. The bright He-weak starHD 49333 does not appear to be a cluster member. A ZAMS fit to acolor-magnitude diagram of the most likely members gives a distancemodulus of (m - M) = 9.15.
| Galactic cluster star radial velocities obtained with a focal reducer field spectrograph. I - The clusters IC 1805, NGC 2287, NGC 2548, IC 4665, NGC 6633, NGC 6940 and NGC 7092
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1985A&AS...62..301G&db_key=AST
| A catalogue of Fe/H determinations, 1984 edition
The present version of the Cayrel de Strobel et al. (1981) catalog ofFe/H abundance ratio determinations contains 1921 values for 1035 stars,which represents an augmentation over the previous publication of 48 and47 percent, respectively. In addition, the literature search conductedis complete up to December, 1983. Stellar metal abundance, effectivetemperature, spectroscopic gravity, spectral type, and photometricindices are covered.
| DDO photometry on red giants in the open clusters NGC 2232, NGC 2287, and NGC 2451
From DDO photometry combined with U, B, V photometry of red stars in theopen clusters NGC 2232, NGC 2287, and NGC 2451, the mean color excess E(B-V), the distance modulus, and the mean metal abundance (Fe/H) werederived for the clusters. The physical parameters, surface gravity,effective temperature, and spectral type were also obtained for the redstars. Estimation of age yielded 1.1 x 10 to the 8th yr for NGC 2287,and for NGC 2451, 4.8 x 10 to the 8th. The cluster NGC 2232 should beolder than 10 to the 9th yr.
| Positions of stars in regions of 14 southern galactic clusters
Positions have been obtained for a total of 3487 stars scattered over 14regions that are centered on each of the southern galactic clusters NGC1981, 2287, 2437, 2451, 2516, 2546, 2547, 2548, 3114, 3532, IC 2391,2395, 2602, and Truempler 10. A frame of reference has been establishedfor each region using ESO Schmidt plates centered on the clusters, witheach plate containing 20-35 measurable Perth 70 stars that are used fordetermining the positions of 200-400 fainter stars within a centralfield of 25 min of arc radius (covering the corresponding 1.5-m plates).
| Spectral morphology in the open cluster NGC 2287
Spectral classifications in NGC 2287 have revealed the presence of anHe-weak star, three Hg-Mn stars, one star with a weak K line, one coolAp star and one star with a composite spectrum. Spectroscopic evidencedetermined eight double-line binaries as well as five suspecteddouble-line binaries.
| Mulitcolor Photometry of the Open Cluster NGC 2287
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1978A&AS...34..241F&db_key=AST
| (R-I) colors of cepheids and yellow supergiants in open clusters.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1976ApJ...203..466S&db_key=AST
| Measurements of polarization and colour of stars in the galactic clusters NGC 2244 and NGC 2287
Not Available
| A Study of the Galactic Cluster NGC 2287.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1954ApJ...119..188C&db_key=AST
|
Додај нови чланак
Линкови у сродству са темом
Додај нови линк
Чланови следећих група \:
|
Посматрања и Астрометриски подаци
| Сазвежђа: | Велики пас |
| Ректацензија: | 06h45m57.46s |
| Deклинација: | -20°46'30.2" |
| Apparent магнитуда: | 6.884 |
| Даљина: | 408.163 parsecs |
| Proper motion RA: | -3.1 |
| Proper motion Dec: | -0.3 |
| B-T magnitude: | 8.855 |
| V-T magnitude: | 7.047 |
Каталог и designations:
|
