Methods for improving open cluster fundamental parameters applied to M 52 and NGC 3960
Aims.We derive accurate parameters related to the CMD, structure anddynamical state of M 52 and NGC 3960, whose fields are affected bydifferential reddening. Previous works estimated their ages in theranges 35-135 Myr and 0.5-1.0 Gyr, respectively. Methods: .J, Hand Ks 2MASS photometry with errors <0.2 mag is used tobuild CMDs, radial density profiles, luminosity and mass functions, andcorrect for differential reddening. Field-star decontamination isapplied to uncover the cluster's intrinsic CMD morphology, andcolour-magnitude filters are used to isolate stars with high probabilityof being cluster members. Results: .The differential-reddeningcorrected radial density profile of M 52 follows King's law with coreand limiting radii of R_core =0.91 ± 0.14 pc and R_lim =8.0± 1.0 pc. NGC 3960 presents an excess of the stellar density overKing's profile (R_core = 0.62 ± 0.11 pc and R_lim =6.0 ±0.8 pc) at the center. The tidal radii of M 52 and NGC 3960 areR_tidal=13.1 ± 2.2 pc and R_tidal=10.7 ± 3.7 pc. Clusterages of M 52 and NGC 3960 derived with Padova isochrones are constrainedto 60 ± 10 Myr and 1.1 ± 0.1 Gyr. In M 52 the core MF(χ_core=0.89 ± 0.12) is flatter than the halo's(χ_halo=1.65 ± 0.12). In NGC 3960 they are χ_core=-0.74± 0.35 and χ_halo=1.26 ± 0.26. The mass locked up inMS/evolved stars in M 52 is ~1200 M_ȯ, and the total mass(extrapolated to 0.08M_ȯ) is ~3800 M_ȯ. The total mass in NGC3960 is ~1300 M_ȯ. Conclusions: .Compared to open clusters indifferent dynamical states studied with similar methods, the core andoverall parameters of M 52 are consistent with an open cluster moremassive than 1000 M_ȯ and ~60 Myr old, with some mass segregationin the inner region. The core of NGC 3960 is in an advanced dynamicalstate with strong mass segregation in the core/halo region, while thesomewhat flat overall MF (χ≈ 1.07) suggests low-mass starevaporation. The excess stellar density in the core may suggestpost-core collapse. The dynamical evolution of NGC 3960 may have beenaccelerated by the tidal Galactic field, since it lies ≈0.5 kpcinside the Solar circle.
|
Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS) - Third edition - Comments and statistics
The Catalogue, available at the Centre de Données Stellaires deStrasbourg, consists of 13 573 records concerning the results obtainedfrom different methods for 7778 stars, reported in the literature. Thefollowing data are listed for each star: identifications, apparentmagnitude, spectral type, apparent diameter in arcsec, absolute radiusin solar units, method of determination, reference, remarks. Commentsand statistics obtained from CADARS are given. The Catalogue isavailable in electronic form at the CDS via anonymous ftp tocdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcar?J/A+A/367/521
|
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
|
DDO Metal Abundances of High-Luminosity Late-Type Stars in Galactic Open Clusters
Results from UBV and DDO photometry are presented for 54 high-luminositylate-type stars in the fields of 23 open clusters. The probability ofcluster membership for each observed star is evaluated using twoindependent photometric criteria. It is found that 32 stars are verylikely cluster members, the remaining ones being almost certainly fieldobjects. The recently improved calibrations of the DDO system have beenused to derive MK spectral types, effective temperatures, andmetallicities, while E(B-V) color excesses have been determined throughknown photometric and spectroscopic procedures. The DDO metallicitiesrange between values typical of moderately metal-poor ([Fe/H]=~ -0.3) tomoderately metal-rich ([Fe/H] =~ 0.2) clusters. The masses of thecluster giants range between 1 and 4 solar masses, with the scatterwithin a cluster being less than 1 solar mass. (SECTION: StellarClusters and Associations)
|
Absolute Magnitudes and Colors of A-F Supergiants from Near-Infrared Features. II. The Galactic Sample
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1995AJ....109.2193S&db_key=AST
|
Estimating absolute magnitudes and colors of A-F supergiants from near-infrared features. I - The Northern Hemisphere
In this paper we consider the calibration of the luminosity sensitive OI 7774 A feature in the A and F supergiants. We have obtained 2-3 Aresolution CCD spectra of this feature for nine A and F supergiants innorthern Galactic clusters. The new data, additional cluster members,and improvements in the various distance estimates have substantiallyimproved the calibration. We show that the intrinsic rms dispersionabout the resulting M(V)-W(lambda) relation for A and F supergiants iscomparable to that of the Cepheid period luminosity relation in thevisual. We have also found that an index measuring the strength of theinfrared calcium triplet provides an excellent indicator of intrinsiccolor among these stars. Together, these two relations suggest that Aand F supergiants could usefully be employed as standard candles out toat least 5 Mpc.
|
Colour excesses and absolute magnitudes for non-Cepheid F-G supergiants from uvbybeta photometry
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1990A&A...239..205A&db_key=AST
|
Behaviour of O I triplet Lambda-7773
Reticon spectra of the O I triplet at 7772-7775-Lambda are analyzed in67 non-peculiar B to F stars. The dependence of the equivalent width ofthe triplet on luminosity, but also on other atmospheric parameters isexamined; predicted intensities are compared with the observed ones andthe effects of microturbulence and NLTE are discussed.
|
Geneva intrinsic colours of the supergiants of spectral types A and F
The aim of this research note is to expose a photometric method todetermine the intrinsic values of the Geneva color index (B2-V1) for thesupergiants of spectral types A and F. The different stages which led tothis objective are presented, and the method is tested with a few starsbelonging to clusters for which color excesses were found in theliterature. A list of stars classified as supergiants which behavephotometrically as dwarfs is indicated.
|
Equivalent width of O I lambda 7774 and absolute magnitude relation for F and G supergiants
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1978MNRAS.183..211R&db_key=AST
|
Evolved stars in open clusters.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1976ApJS...30..451H&db_key=AST
|
Photometry of the near-infrared O I feature in A- and F-type stars
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1974AJ.....79.1416S&db_key=AST
|
Photoelectric Equivalent Widths of the OIλ7774 Line and M_{υ}'s of Selected F Supergiants
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1974PASP...86...33B&db_key=AST
|
On the relationship between the apparent magnitudes given in several catalogues and the UBV system.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1974A&AS...15..215O&db_key=AST
|
Be Stars in the Galactic Cluster M 52
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1973PASP...85..405B&db_key=AST
|
The Temperature Scale of F and G Stars. I. Hydrogen Line Profiles
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1972ApJ...174..595S&db_key=AST
|
The Atmospheres of the F-Type Supergiants II. The Line and Continuous Spectra
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1972ApJS...24..255O&db_key=AST
|
The Atmospheres of the F-Type Supergiants I. Calibration of the Luminosity-Sensitive O i Lambda 7774 Line
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1972ApJS...24..247O&db_key=AST
|
Nonvariable Supergiants in the Cepheid Instability Strip.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1972ApJ...172..679S&db_key=AST
|
Photometric data for 139 supergiants.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1972AJ.....77..150F&db_key=AST
|
The space distribution and kinematics of supergiants
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1970AJ.....75..602H&db_key=AST
|
Etude cinematique et photometrique d'une region de Cas.
Not Available
|
Color Excesses for Supergiants and Classical Cepheids.VI. on the Intrinsic Colors and the Hess Diagram of Late-Type Supergiants.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1961ApJ...134..850K&db_key=AST
|
Überriesen FO-K7 Ia-II in galaktischen Sterhaufen. I. Mittelung von: Leuchtkraft, Alter und Eigenfarben galaktischer Überriesen. Mit 3 Textabbildungen
Not Available
|
The Galactic Cluster NGC 7654 (M 52).
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1960ApJ...132..689P&db_key=AST
|
La mesure des vitesses radiales au prisme objectif. IX - 3e liste de vitesses radiales déterminées au prisme objectif à vision directe
Not Available
|
Color Excesses from Six-Color Photometry of Supergiant Stars
Not Available
|
Spectral Classification of Nine Stars
Not Available
|
Helligkeits messungen im Sternhaufen Messier 52 (NGC 7654)
Not Available
|
