Contingut
Imatges
Carregar la teva Imatge
DSS Images Other Images
Articles Relacionats
New stellar members of the Coma Berenices open star cluster
We present the results of a survey of the Coma Berenices open starcluster (Melotte 111), undertaken using proper motions from theUSNO-B1.0 (United States Naval Observatory) and photometry from theTwo-Micron All-Sky Survey (2MASS) Point Source catalogues. We haveidentified 60 new candidate members with masses in the range 1.007
| Abundances of A/F and Am/Fm stars in open clusters as constraints to self-consistent models including transport processes
We describe the current status of a programme we started a few years agoto observe a large number of A/F and Am/Fm stars in open clusters ofvarious ages. Spectra were obtained with the AURELIE and ELODIEspectrographs at a resolving power of about 40000 and S/N ratios from100 up to 500. Abundances of 11 chemical elements have been derived byusing Takeda's (1995) procedure. A short review on previous abundancedeterminations of A and F dwarfs in open clusters and a progress reporton the current status of this project are presented. New abundancedeterminations for 24 A and F dwarfs in the Coma Berenices cluster arepresented. These abundance determinations serve to set constraints toself-consistent evolutionary models of A and F stars including transportprocesses.
| Improved Hipparcos Parallaxes of Coma Berenices and NGC 6231
A method to reprocess the Hipparcos Intermediate Astrometry Data thatreduces the propagation of the along-scan spacecraft attitude errors wasdeveloped and successfully used to obtain a more consistent parallax ofthe Pleiades (Makarov, published in 2002). The same technique is usednow to correct the Hipparcos parallaxes of the Coma Berenices and NGC6231 open clusters, which are also in error. The new mean parallax ofComa is 12.40+/-0.17 mas (against previously 11.43 mas) and of NGC 62311.7+/-0.4 mas (against previously -0.8 mas). The new data for Coma arein excellent agreement with the pre-Hipparcos main-sequence fittingestimates. All six members of NGC 6231 that have negative parallaxes inHipparcos obtain positive parallaxes. These results suggest that themain source of astrometric error has been correctly identified, and thata more accurate Hipparcos catalog can be computed.
| The Century Survey Galactic Halo Project. I. Stellar Spectral Analysis
The Century Survey Galactic Halo Project is a photometric andspectroscopic survey from which we select relatively blue stars(V-R<0.30 mag) as probes of the Milky Way halo. The survey stripspans the range of Galactic latitude 35°
| Rotational velocities of A-type stars in the northern hemisphere. II. Measurement of v sin i
This work is the second part of the set of measurements of v sin i forA-type stars, begun by Royer et al. (\cite{Ror_02a}). Spectra of 249 B8to F2-type stars brighter than V=7 have been collected at Observatoirede Haute-Provence (OHP). Fourier transforms of several line profiles inthe range 4200-4600 Å are used to derive v sin i from thefrequency of the first zero. Statistical analysis of the sampleindicates that measurement error mainly depends on v sin i and thisrelative error of the rotational velocity is found to be about 5% onaverage. The systematic shift with respect to standard values fromSlettebak et al. (\cite{Slk_75}), previously found in the first paper,is here confirmed. Comparisons with data from the literature agree withour findings: v sin i values from Slettebak et al. are underestimatedand the relation between both scales follows a linear law ensuremath vsin inew = 1.03 v sin iold+7.7. Finally, thesedata are combined with those from the previous paper (Royer et al.\cite{Ror_02a}), together with the catalogue of Abt & Morrell(\cite{AbtMol95}). The resulting sample includes some 2150 stars withhomogenized rotational velocities. Based on observations made atObservatoire de Haute Provence (CNRS), France. Tables \ref{results} and\ref{merging} are only available in electronic form at the CDS viaanonymous ftp to cdsarc.u-strasbg.fr (130.79.125.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/393/897
| Astrometric radial velocities. III. Hipparcos measurements of nearby star clusters and associations
Radial motions of stars in nearby moving clusters are determined fromaccurate proper motions and trigonometric parallaxes, without any use ofspectroscopy. Assuming that cluster members share the same velocityvector (apart from a random dispersion), we apply a maximum-likelihoodmethod on astrometric data from Hipparcos to compute radial and spacevelocities (and their dispersions) in the Ursa Major, Hyades, ComaBerenices, Pleiades, and Praesepe clusters, and for theScorpius-Centaurus, alpha Persei, and ``HIP 98321'' associations. Theradial motion of the Hyades cluster is determined to within 0.4 kms-1 (standard error), and that of its individual stars towithin 0.6 km s-1. For other clusters, Hipparcos data yieldastrometric radial velocities with typical accuracies of a few kms-1. A comparison of these astrometric values withspectroscopic radial velocities in the literature shows a good generalagreement and, in the case of the best-determined Hyades cluster, alsopermits searches for subtle astrophysical differences, such as evidencefor enhanced convective blueshifts of F-dwarf spectra, and decreasedgravitational redshifts in giants. Similar comparisons for the ScorpiusOB2 complex indicate some expansion of its associations, albeit slowerthan expected from their ages. As a by-product from the radial-velocitysolutions, kinematically improved parallaxes for individual stars areobtained, enabling Hertzsprung-Russell diagrams with unprecedentedaccuracy in luminosity. For the Hyades (parallax accuracy 0.3 mas), itsmain sequence resembles a thin line, possibly with wiggles in it.Although this main sequence has underpopulated regions at certaincolours (previously suggested to be ``Böhm-Vitense gaps''), suchare not visible for other clusters, and are probably spurious. Futurespace astrometry missions carry a great potential for absoluteradial-velocity determinations, insensitive to the complexities ofstellar spectra. Based on observations by the ESA Hipparcos satellite.Extended versions of Tables \ref{tab1} and \ref{tab2} are available inelectronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr(130.79.125.8) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/381/446
| 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
| On the Variability of A3-F0 Luminosity Class III-V Stars
I investigate the Hipparcos Satellite photometry of A3-F0 stars ofluminosity classes III-V to learn about their variability and identify afew stars for which further study is desirable.
| The Pleiades, Coma, Hyades, and Praesepe open clusters: Li, Al, Si, S, Fe, Ni, and Eu abundances compared in A stars
In the third of a series of papers on the A stars in open clusters, theComa and Hyades clusters are revisited; in the first and second papers,the Pleiades and Praesepe were respectively investigated. All thespectra were secured with the Canada-France-Hawaii telescope at highspectral resolution and high signal-to-noise ratios. Photosphericabundances have been determined for Li, Al, Si, S, Fe, Ni, and Eu frommodel atmosphere abundance analysis. All the A stars with enough-sharplines to be studied for Li were observed in the four clusters. Abundanceresults are summarized for 31 cluster members, including 21 Am, 7 normalA, and 3 early-A stars. The Am stars have very uniform Li, Al, Si, S,and Fe abundances in a large temperature range of nearly 1000 K.Compared to normal A stars, Li is significantly deficient in Am stars(by a factor of 3), Al marginally overabundant, Si, S, and Fe are thesame, Ni and Eu (with only a few results) overabundant. Those uniformabundances of Li, Al, Si, S, or Fe in Am stars involve that abundancesare little affected by the magnitude of the rotational velocity. Forboth Am and normal A samples, no abundance trend as a function of ageand/or evolution is detected in the case of Li, Al, Si, S, or Fe. Theages considered are in the range 0.8 - 7 108 years; theevolution is limited from the ZAMS to the cluster turn-off. The build-upof the chemical abundances studied, in particular the Li differentiationbetween Am and normal A stars, could have taken place very early whenthe stars arrive on the Main Sequence. The spread in lithium found forthe A stars is reminiscent of that reported in the field and one opencluster for stars of nearly the same mass and slightly evolved out ofthe Main Sequence. The Li abundance does not change as soon as the starevolves through the subgiant phase and the convection zone becomesdeeper. There are two exceptional Am stars: one, in the Hyades, isLi-deficient and the other, in Praesepe, Li-overabundant. They are noobvious circumstances that can distinguish both stars from others in thevery same region of their respective cluster sequence. In each of thefour clusters, the maximum Li abundance is found in A stars, generallyin normal A stars. The Fe abundance of both Am and normal A groups isfound to be twice the original Fe value (on the ZAMS) in each of thefour clusters, independently of their age or metallicity. It is wellestablished for the Am group and in only a narrow range of Teff for thenormal A group. This behavior is unexpected for normal A stars which arethought to have their original abundances and Fe abundance differentfrom that of Am stars. A larger normal A sample is needed to concludeanything. Our abundance results for cluster Am stars quantitativelyagree with predictions of new models coupling atomic diffusion withturbulent transport (Richer et al. \cite{richer99}). Based onobservations collected at the Canada-France-Hawaii telescope (Hawaii)
| Binaries in the Praesepe and Coma Star Clusters and Their Implications for Binary Evolution
This completes a study of the evolution of binary systems in five openclusters of various ages. Among 21 stars observed in Praesepe, eight arefound or confirmed to be spectroscopic binaries and orbital elements arederived, while one more shows long-term binary motion. Among 18 starsobserved in the Coma Berenices cluster, five are found or confirmed tobe spectroscopic binaries and orbital elements are derived, while asixth has tentative elements. Among five clusters studied we searchedfor three expected evolutionary effects, namely an increase with age inthe mass ratios, a decrease with age of the binary periods, and anincrease in binary frequencies. We find that there is a progression (atthe 3 sigma level) from no binaries out of 10 with mass ratios greaterthan 0.5 in the youngest cluster (combined with the published resultsfor NGC 6193) to 25% such stars in the intermediate-age clusters to 43%such stars in these two oldest clusters. There is no evidence for anincrease in short-period binaries with age. And there is slight evidence(at the 1 sigma level) for an increase with age from 15% to 28% in thefraction of large-amplitude binaries. These results are mostlyconsistent with the idea that most binaries are formed or modified inthree-body interactions, and successive generations of formation anddisruptions tend to form binaries with larger mass ratios. However, partof the initial generation of binaries is probably primordial.
| An astrometric catalogue for the area of Coma Berenices
A catalogue of stellar positions and proper motions down to the 14thphotographic magnitude in the area of the open cluster in Coma Berenicesis compiled from data of 12 different sources. The accuracy of theproper motion data is comparable to that of the Hipparcos Catalogue. Thecatalogue Table 5 is only available in electronic form at the CDS viaanonymous 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
| The Coma Berenices star cluster and its moving group
We report on the analysis of astrometric and photometric data fromHipparcos, Tycho and the ACT catalogue in a 1200 sq. degree field aroundthe nearby open star cluster in Coma Berenices and infer thecharacteristic features of this cluster. From a sample of 51 kinematicmembers we derive the cluster's distance, size and spatial structure aswell as its stellar content, mass and age. We find that the clusterconsists of an elliptical core-halo system with major axis parallel tothe direction of galactic motion, and of a moving group of extratidalstars. The latter have tangential distances >= 10 pc from the clustercenter, but have the same distance from the Sun, the same motion and thesame age as the stars in the core and halo. The luminosity function ofthe core-halo system steeply declines beyond absolute magnitude M_V=4.5,but that of the moving group rises towards fainter magnitudes andsuggests the existence of further low-mass members below the currentmagnitude limit. The cloud of extratidal stars witnesses the process ofdissolution of the cluster.
| On the HIPPARCOS photometry of chemically peculiar B, A, and F stars
The Hipparcos photometry of the Chemically Peculiar main sequence B, A,and F stars is examined for variability. Some non-magnetic CP stars,Mercury-Manganese and metallic-line stars, which according to canonicalwisdom should not be variable, may be variable and are identified forfurther study. Some potentially important magnetic CP stars are noted.Tables 1, 2, and 3 are available only in electronic form at the CDS viaanonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/Abstract.html
| Metal abundances of A-type stars in galactic clusters. II. Pleiades, Coma Berenices, Hyades, and Praesepe
A study of chemical composition for 23 A-type stars in four nearby openclusters (Pleiades, Coma, Hyades and Praesepe) has derived detailedabundances for Mg, Ca, Sc, Cr, Fe, and Ni from high resolutionspectroscopy. These results are discussed using the microscopicdiffusion model, which yields time-dependent element stratifications asin the case of Am stars. For the Pleiades, the youngest cluster, we findseveral atypical abundance patterns, which may be transient phases ofthe Am phenomenon. The members of the older clusters show globally moreclassical patterns. Based on observations collected at the Observatoirede Haute-Provence (France)
| Spectrophotometry of 237 Stars in 7 Open Clusters
Spectrophotometry is presented for 237 stars in 7 nearby open clusters:Hyades, Pleiades, Alpha Persei, Praesepe, Coma Berenices, IC 4665, andM39. The observations were taken by Lee McDonald and David Bursteinusing the Wampler single-channel scanner on the Crossley 0.9m telescopeat Lick Observatory from July 1973 through December 1974. Sixteenbandpasses spanning the spectral range 3500 Angstroms to 7780 Angstromswere observed for each star, with bandwidths 32Angstroms, 48 Angstromsor 64 Angstroms. Data are standardized to the Hayes-Latham system tomutual accuracy of 0.016 mag per passband. The accuracy of thespectrophotometry is assessed in three ways on a star-by-star basis.First, comparisons are made with previously published spectrophotometryfor 19 stars observed in common. Second, (B-V) colors and uvby colorsare compared for 236 stars and 221 stars, respectively. Finally,comparsions are made for 200 main sequence stars to the spectralsynthesis models of Kurucz, fixing log g = 4.0 and [Fe/H] = 0.0, andonly varying effective temperature. The accuracy of tests using uvbycolors and the Kurucz models are shown to track each other closely,yielding an accuracy estimate (1 sigma ) of 0.01 mag for the 13 colorsformed from bandpasses longward of the Balmer jump, and 0.02 mag for the3 colors formed from the three bandpasses below the Balmer jump. Incontrast, larger scatter is found relative to the previously publishedspectrophotometry of Bohm-Vitense & Johnson (16 stars in common) andGunn & Stryker (3 stars). We also show that the scatter in the fitsof the spectrophotometric colors and the uvby filter colors is areasonable way to identify the observations of which specific stars areaccurate to 1 sigma , 2 sigma , .... As such, the residuals from boththe filter color fits and the Kurucz model fits are tabulated for eachstar where it was possible to make a comparison, so users of these datacan choose stars according to the accuracy of the data that isappropriate to their needs. The very good agreement between the modelsand these data verifies the accuracy of these data, and also verifiesthe usefulness of the Kurucz models to define spectrophotometry forstars in this temperature range (>5000 K). These data define accuratespectrophotometry of bright, open cluster stars that can be used as asecondary flux calibration for CCD-based spectrophotometric surveys.
| 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
| Atmospheric chemical composition of Am stars in the Coma cluster
Not Available
| Coronal activity in the Coma Berenices open cluster.
We present ROSAT PSPC observations of the ~500Myr old Coma Berenicescluster. The X-ray survey in Coma consists of a) a raster scan of shortduration PSPC pointings, b) ROSAT All-Sky Survey data, and c) a 16ksecdeep PSPC pointing. The raster scan and the survey data were mergedtogether covering an area of about 36 square degrees, while the deeppointing was analyzed separately. No major differences were foundbetween the two datasets. Our ROSAT observations indicate that Coma ismuch more similar in its X-ray properties to the coeval Hyades than tothe also coeval Praesepe cluster. As in the Hyades, almost all late-Fand G stars were detected, also showing a comparable range in X-rayluminosity. X-ray luminosity distribution functions (XLDFs) forsolar-type members are in close agreement with those of the Hyades,confirming that the majority of Praesepe's members are less luminousthan what one would expect for stars of their age. The Coma Berenicescluster is known for its apparent deficit of low mass stars of spectraltype K and later. We present 12 new possible low-mass Coma candidates,identified through this X-ray survey.
| The Relation between Rotational Velocities and Spectral Peculiarities among A-Type Stars
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1995ApJS...99..135A&db_key=AST
| A catalog of far-ultraviolet point sources detected with the fast FAUST Telescope on ATLAS-1
We list the photometric measurements of point sources made by the FarUltraviolet Space Telescope (FAUST) when it flew on the ATLAS-1 spaceshuttle mission. The list contains 4698 Galactic and extragalacticobjects detected in 22 wide-field images of the sky. At the locationssurveyed, this catalog reaches a limiting magnitude approximately afactor of 10 fainter than the previous UV all-sky survey, TDl. Thecatalog limit is approximately 1 x 10-14 ergs A sq cm/s,although it is not complete to this level. We list for each object theposition, FUV flux, the error in flux, and where possible anidentification from catalogs of nearby stars and galaxies. Thesecatalogs include the Michigan HD (MHD) and HD, SAO, the HIPPARCOS InputCatalog, the Position and Proper Motion Catalog, the TD1 Catalog, theMcCook and Sion Catalog of white dwarfs, and the RC3 Catalog ofGalaxies. We identify 2239 FAUST sources with objects in the stellarcatalogs and 172 with galaxies in the RC3 catalog. We estimate thenumber of sources with incorrect identifications to be less than 2%.
| A Study of Ultraviolet Objects near the North Galactic Pole with FAUST
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1995ApJ...450..137B&db_key=AST
| 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.
| The structure of the galactic halo outside the solar circle as traced by the blue horizontal branch stars
A complete sample of blue horizontal branch (BHB) stars in the magnituderange 13.0 less than or equal to V less than or equal to 16.5 isisolated in two Galactic fields that have previously been searched forRR Lyrae variables: SA 57 in the Northern Polar Cap and the LickAstrograph field RR 7 in the Anticenter (l = 183 deg, b = +37 deg).These BHB stars are a subset of the AF stars found in the CaseLow-Dispersion Northern Survey; lists of these AF stars were madeavailable by the late Nick Sanduleak. In the color range 0.00 less thanor equal to (B - V)0 less than or equal to +0.20, we candistinguish the BHB stars among these AF stars by comparing them bothwith well known local field horizontal branch (FHB) stars and also theBHB members of the halo globular clusters M3 and M92. The criteria forthis comparison include (1) a (u - B)K color index (derivedfrom photoelectric observations using the Stroemgren u filter and theJohnson B and V filters) that measures the size of the Balmer jump, (2)a spectrophotometric index lambda that measures the steepness of theBalmer jump, and (3) a parameter D0.2 that is the mean widthof the H-delta and H-gamma Balmer lines measured at 20 percent of thecontinuum level. These criteria give consistent results in separatingBHB stars from higher gravity main sequence AF stars in the color range0.00 less than or equal to (B - V)0 less than or equal to+0.20. All three photometric and spectrophotometric criteria weremeasured for 35 stars in the SA 57 field and 37 stars in the RR 7 fieldthat are in the color range (B - V)0 less than or equal to+0.23 and in the magnitude range 13.0 less than or equal to V less thanor equal to 16.5. For a small number of additional stars only (u -B)K was obtained. Among the AF stars that are fainter than B= 13 and bluer than (B - V)0 = +0.23, about half of those inthe SA 57 field and about one third of those in the lower latitude RR 7field are BHB stars. Isoabundance contours were located empirically inplots of the pseudoequivalent width versus (B - V)0 for thelines of Mg II lambda-4481 A, Ca II lambda-3933 A, and Fe I lambda-4272A. Solar abundances were defined by the data from main sequence stars inthe Pleiades and Coma open clusters. Data from the BHB stars in M3 andM92 defined the (Fe/H) = -1.5 and -2.2 isoabundance contours,respectively. Metallicities of all stars were estimated by interpolatingthe measured pseudoequivalent widths in these diagrams at the observed(B - V)0. The distribution of (Fe/H) found for the BHB starsin this way is very similar to that which we found for the RR Lyraestars in the same fields using the Preston Delta-S method. The spacedensities of these BHB stars were analyzed both separately and togetherwith earlier observations of field BHB stars. This analysis supports atwo-component model for the halo of our Galaxy that is similar in manyrespects to that proposed by Hartwick although our discussion refersonly to the region outside the solar circle.
| Possible presence of magnetic fields and iron content of atmospheres of "metallic" Am-stars.
Not Available
| Measurement and Analysis of Rotation in Close Binary Stars - Part One - Observations and Results
Not Available
| Member stars of the open cluster Mel 111 in Coma Berenices
Proper motions of AGK3 stars in a 6 x 6 deg field centered on the opencluster Mel 111 in Coma Berenices have been used for selecting starswhich are probable members of the cluster. Available photometric dataand radial velocities have been used to refine the selection. Seventeennew candidates are proposed.
| Effective temperature of AP and AM stars from Geneva photometry
The determination of the effective temperature of different kinds ofchemically peculiar stars from Geneva photometry is rediscussed. Wepropose an improved method of determining T(eff) of Ap stars fromGeneva's reddening-free X and Y parameters or from the B2-G index. Theeffect of duplicity on the determination of T(eff) of Am stars isdiscussed.
| The consistency of Stromgren-beta photometry for northern galactic clusters. I - The Hyades and Coma
We have compared the Hyades, Coma, and a set of field standard stars inthe V and Stromgren-beta systems. If Stromgren data by Crawford and hiscollaborators (1966, 1969, 1970) are considered, all the data turn outto be on the same system; no corrections as large as several mmag arerequired to achieve this state. For beta, similar consistency betweenthe Hyades and Coma is already known to exist. We find that for thestandard stars, beta values from the literature are consistent with theHyades-Coma system. For V, we adopt corrections derived previously byJoner and Taylor (1990) for published cluster photometry. Given thesecorrections, we find that within rather generous accidental-errorlimits, the V systems for the field stars and the clusters agree.
| Liste des étoiles Ap et Am dans les amas ouverts (édition révisée)
Not Available
|
Enviar un nou article
Enllaços Relacionats
- - No s'ha trobat enllaços -
Enviar un nou enllaç
Membre dels grups següents:
|
Dades d'Observació i Astrometria
| Constel·lació: | Coma Berenices |
| Ascensió Recta: | 12h33m34.20s |
| Declinació: | +24°16'59.0" |
| Magnitud Aparent: | 6.29 |
| Distancia: | 106.27 parsecs |
| Moviment propi RA: | -11.3 |
| Moviment propi Dec: | -8.2 |
| B-T magnitude: | 6.399 |
| V-T magnitude: | 6.26 |
Catàlegs i designacions:
|
