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First results from the ESO VLTI calibrators program
The ESO Very Large Telescope Interferometer (VLTI) is one of the leadinginterferometric facilities. It is equipped with several 8.2 and 1.8 mtelescopes, a large number of baselines up to 200 m, and with severalsubsystems designed to enable high quality measurements and to improvesignificantly the limits of sensitivities currently available tolong-baseline interferometry. The full scientific potential of the VLTIcan be exploited only if a consistent set of good quality calibrators isavailable. For this, a large number of observations of potentialcalibrators have been obtained during the commissioning phase of theVLTI. These data are publicly available. We briefly describe theinterferometer, the VINCI instrument used for the observations, the dataflow from acquisition to processed results, and we present and commenton the volume of observations gathered and scrutinized. The result is alist of 191 calibrator candidates, for which a total of 12 066observations can be deemed of satisfactory quality. We present a generalstatistical analysis of this sample, using as a starting point theangular diameters previously available in the literature. We derive thegeneral characteristics of the VLTI transfer function, and its trendwith time in the period 2001 through mid-2004. A second paper will bedevoted to a detailed investigation of a selected sample, aimed atestablishing a VLTI-based homogeneous system of calibrators.
| Nearby early-type galaxies with ionized gas. I. Line-strength indices of the underlying stellar population
With the aim of building a data-set of spectral properties of wellstudied early-type galaxies showing emission lines, we presentintermediate resolution spectra of 50 galaxies in the nearby Universe.The sample, which covers several of the E and S0 morphologicalsub-classes, is biased toward objects that might be expected to haveongoing and recent star formation, at least in small amounts, because ofthe presence of the emission lines. The emission is expected to comefrom the combination of active galactic nuclei and star formationregions within the galaxies. Sample galaxies are located in environmentscorresponding to a broad range of local galaxy densities, althoughpredominantly in low density environments. Our long-slit spectra coverthe 3700-7250 Å wavelength range with a spectral resolution of≈7.6 Å at 5550 Å. The specific aim of this paper, and ourfirst step in the investigation, is to map the underlying galaxy stellarpopulation by measuring, along the slit positioned along the galaxymajor axis, line-strength indices at several, homogeneousgalacto-centric distances. For each object we extracted 7luminosity-weighted apertures (with radii 1.5´´,2.5´´, 10´´, r_e/10, r_e/8, r_e/4 and r_e/2)corrected for the galaxy ellipticity and 4 gradients (0 ≤ r ≤r_e/16, r_e/16 ≤ r ≤ r_e/8, r_e/8 ≤ r ≤ r_e/4 and r_e/4≤ r ≤ r_e/2). For each aperture and gradient we measured 25line-strength indices: 21 of the set defined by the Lick-IDS“standard” system (Trager et al. [CITE], ApJS, 116, 1) and 4introduced by Worthey & Ottaviani ([CITE], ApJS, 111, 377).Line-strength indices have been transformed to the Lick-IDS system.Indices derived then include Hβ, Mg1, Mg2, Mgb, MgFe, Fe5270,Fe5335 commonly used in classic index-index diagrams. The paperintroduces the sample, presents the observations, describes the datareduction procedures, the extraction of apertures and gradients, thedetermination and correction of the line-strength indices, the procedureadopted to transform them into the Lick-IDS System and the proceduresadopted for the emission correction. We finally discuss the comparisonsbetween our dataset and line-strength indices available in theliterature. A significant fraction, about 60%, of galaxies in thepresent sample has one previous measurement in the Lick-IDS system butbasically restricted within the r_e/8 region. Line-strength measuresobtained both from apertures and gradients outside this area and withinthe r_e/8 region, with the present radial mapping, are completely new.Full appendix and Figs. 8 to 13 are only available in electronic form athttp://www.edpsciences.org Full Tables 6, 7, 9 and 10 are only availableat 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/433/497 Based onobservations obtained at the European Southern Observatory, La Silla,Chile (Programs Nr. 60.A-0647 and 61.A-0406).
| CHARM2: An updated Catalog of High Angular Resolution Measurements
We present an update of the Catalog of High Angular ResolutionMeasurements (CHARM, Richichi & Percheron \cite{CHARM}, A&A,386, 492), which includes results available until July 2004. CHARM2 is acompilation of direct measurements by high angular resolution methods,as well as indirect estimates of stellar diameters. Its main goal is toprovide a reference list of sources which can be used for calibrationand verification observations with long-baseline optical and near-IRinterferometers. Single and binary stars are included, as are complexobjects from circumstellar shells to extragalactic sources. The presentupdate provides an increase of almost a factor of two over the previousedition. Additionally, it includes several corrections and improvements,as well as a cross-check with the valuable public release observationsof the ESO Very Large Telescope Interferometer (VLTI). A total of 8231entries for 3238 unique sources are now present in CHARM2. Thisrepresents an increase of a factor of 3.4 and 2.0, respectively, overthe contents of the previous version of CHARM.The catalog is only available in electronic form at the CDS viaanonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/431/773
| Synthetic Lick Indices and Detection of α-enhanced Stars. II. F, G, and K Stars in the -1.0 < [Fe/H] < +0.50 Range
We present an analysis of 402 F, G, and K solar neighborhood stars, withaccurate estimates of [Fe/H] in the range -1.0 to +0.5 dex, aimed at thedetection of α-enhanced stars and at the investigation of theirkinematical properties. The analysis is based on the comparison of 571sets of spectral indices in the Lick/IDS system, coming from fourdifferent observational data sets, with synthetic indices computed withsolar-scaled abundances and with α-element enhancement. We useselected combinations of indices to single out α-enhanced starswithout requiring previous knowledge of their main atmosphericparameters. By applying this approach to the total data set, we obtain alist of 60 bona fide α-enhanced stars and of 146 stars withsolar-scaled abundances. The properties of the detected α-enhancedand solar-scaled abundance stars with respect to their [Fe/H] values andkinematics are presented. A clear kinematic distinction betweensolar-scaled and α-enhanced stars was found, although a one-to-onecorrespondence to ``thin disk'' and ``thick disk'' components cannot besupported with the present data.
| J - K DENIS photometry of a VLTI-selected sample of bright southern stars
We present a photometric survey of bright southern stars carried outusing the DENIS instrument equipped with attenuating filters. Theobservations were carried out not using the survey mode of DENIS, butwith individual target pointings. This project was stimulated by theneed to obtain near-infrared photometry of stars to be used in earlycommissioning observations of the ESO Very Large TelescopeInterferometer, and in particular to establish a network of brightcalibrator sources.We stress that near-infrared photometry is peculiarly lacking for manybright stars. These stars are saturated in 2MASS as well as in regularDENIS observations. The only other observations available for brightinfrared stars are those of the Two Micron Sky Survey dating from overthirty years ago. These were restricted to declinations above≈-30°, and thus cover only about half of the sky accessible fromthe VLTI site.We note that the final 2MASS data release includes photometry of brightstars, obtained by means of point-spread function fitting. However, thismethod only achieves about 30% accuracy, which is not sufficient formost applications.In this work, we present photometry for over 600 stars, each with atleast one and up to eight measurements, in the J and K filters. Typicalaccuracy is at the level of 0\fm05 and 0\fm04 in the J and K_s bands,respectively.Based on observations collected at the European Southern Observatory, LaSilla.Tables 1 and 2 are 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/cgi-bin/qcat?J/A+A/413/1037
| Interrelations between V il and S tr photometric systems: The luminosity indicator (v - X)
Using the largest database of near-IR Ca II Triplet indices currentlyavailable (Cenarro et al. \cite{Cenarro01a},b), we confirm our findingabout the influence of the Ca II stellar lines on the X magnitude ofthe Vilnius photometric system. This effect is significant for spectralsub-classes from early F until mid K. For this spectral range there is alinear relation between the v-X index and the strength of the infraredCa II Triplet, which implies that the Ca II H&K lines shouldinfluence the difference in a similar way. For the spectral intervalstudied, v-X repeats the behavior of the Ca II Triplet with respect togravity, temperature and metallicity. The Ca II Triplet lines are apowerful diagnostic of the stellar populations in galaxies because oftheir sensitivity to the main stellar atmospheric parameters. Being mucheasily achievable observationally and virtually reddening free, the v-Xindex may find similar applications. v-X is log g sensitive butadditional means are required to break the dwarf - giant duplicity. Forthis purpose we have studied the variation of thev(Strömgren)-B(Johnson) index with gravity, temperature and theequivalent width of the Ca II Triplet. Sincev(Strömgren)-B(Johnson) have a none overlapping variation with theCa II Triplet the dwarfs and giants may be separated and Teffand log g may be estimated. The v(Strömgren)-B(Johnson) index hasfurthermore the advantage that E(v-B) ~ 0.25E(B-V).Based on CDS data.
| A Study of the Direct Fitting Method for Measurement of Galaxy Velocity Dispersions
We have measured the central stellar velocity dispersions of 33 nearbyspiral and elliptical galaxies, using a straightforward template-fittingalgorithm operating in the pixel domain. The spectra, obtained with theDouble Spectrograph at Palomar Observatory, cover both the Ca tripletand the Mg I b region, and we present a comparison of the velocitydispersion measurements from these two spectral regions. Model fits tothe Ca triplet region generally yield good results, with littlesensitivity to the choice of template star. In contrast, the Mg I bregion is more sensitive to template mismatch and to details of thefitting procedure, such as the order of a polynomial used to match thecontinuum shape of the template to the object. As a consequence of thecorrelation of the [Mg/Fe] ratio with velocity dispersion, it isdifficult to obtain a satisfactory model fit to the Mg I b lines and thesurrounding Fe blends simultaneously, particularly for giant ellipticalgalaxies with large velocity dispersions. We demonstrate that if themetallicities of the galaxy and template star are not well matched, thendirect template-fitting results are improved if the Mg I b linesthemselves are excluded from the fit and the velocity dispersion isdetermined from the surrounding weaker lines.
| A catalogue of calibrator stars for long baseline stellar interferometry
Long baseline stellar interferometry shares with other techniques theneed for calibrator stars in order to correct for instrumental andatmospheric effects. We present a catalogue of 374 stars carefullyselected to be used for that purpose in the near infrared. Owing toseveral convergent criteria with the work of Cohen et al.(\cite{cohen99}), this catalogue is in essence a subset of theirself-consistent all-sky network of spectro-photometric calibrator stars.For every star, we provide the angular limb-darkened diameter, uniformdisc angular diameters in the J, H and K bands, the Johnson photometryand other useful parameters. Most stars are type III giants withspectral types K or M0, magnitudes V=3-7 and K=0-3. Their angularlimb-darkened diameters range from 1 to 3 mas with a median uncertaintyas low as 1.2%. The median distance from a given point on the sky to theclosest reference is 5.2degr , whereas this distance never exceeds16.4degr for any celestial location. The catalogue 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/393/183
| CHARM: A Catalog of High Angular Resolution Measurements
The Catalog of High Angular Resolution Measurements (CHARM) includesmost of the measurements obtained by the techniques of lunaroccultations and long-baseline interferometry at visual and infraredwavelengths, which have appeared in the literature or have otherwisebeen made public until mid-2001. A total of 2432 measurements of 1625sources are included, along with extensive auxiliary information. Inparticular, visual and infrared photometry is included for almost allthe sources. This has been partly extracted from currently availablecatalogs, and partly obtained specifically for CHARM. The main aim is toprovide a compilation of sources which could be used as calibrators orfor science verification purposes by the new generation of largeground-based facilities such as the ESO Very Large Interferometer andthe Keck Interferometer. The Catalog is available in electronic form atthe 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/386/492, and from theauthors on CD-Rom.
| Lick Spectral Indices for Super-Metal-rich Stars
We present Lick spectral indices for a complete sample of 139 candidatesuper-metal-rich stars of different luminosity classes (MK type from Ito V). For 91 of these stars we were able to identify, in anaccompanying paper, the fundamental atmosphere parameters. This confirmsthat at least 2/3 of the sample consists of stars with [Fe/H] in excessof +0.1 dex. Optical indices for both observations and fiducialsynthetic spectra have been calibrated to the Lick system according toWorthey et al. and include the Fe I indices of Fe5015, Fe5270, andFe5335 and the Mg I and MgH indices of Mg2 and Mg b at 5180Å. The internal accuracy of the observations is found to beσ(Fe5015)=+/-0.32 Å, σ(Fe5270)=+/-0.19 Å,σ(Fe5335)=+/-0.22 Å, σ(Mg2)=+/-0.004 mag,and σ(Mg b)=+/-0.19 Å. This is about a factor of 2 betterthan the corresponding theoretical indices from the synthetic spectra,the latter being a consequence of the intrinsic limitations in the inputphysics, as discussed by Chavez et al. By comparing models andobservations, we find no evidence for nonstandard Mg versus Fe relativeabundance, so [Mg/Fe]=0, on the average, for our sample. Both theWorthey et al. and Buzzoni et al. fitting functions are found tosuitably match the data and can therefore confidently be extended forpopulation synthesis application also to supersolar metallicity regimes.A somewhat different behavior of the two fitting sets appears, however,beyond the temperature constraints of our stellar sample. Its impact onthe theoretical output is discussed, as far as the integratedMg2 index is derived from synthesis models of stellaraggregates. A two-index plot, such as Mg2 versus Fe5270, isfound to provide a simple and powerful tool for probing distinctiveproperties of single stars and stellar aggregates as a whole. The majoradvantage, over a classical CM diagram, is that it is both reddeningfree and distance independent. Based on observations collected at theInstituto Nacional de Astrofísica, Optica y Electrónica(INAOE) ``G. Haro'' Observatory, Cananea (Mexico).
| The Ratio of α-Elements to Iron in Early-Type Galaxies from TIO and MG2
In order to derive the ratio of α-elements to iron in galaxies, wehave observed the strongest TiO band heads of the γ and γ'systems at 7000-7500 Å in a sample of a dozen early-type galaxies.The equivalent widths of the TiO bands are compared with syntheticspectra for single-aged stellar populations and composite galaxy models,all computed with [α/Fe]=0.0 and +0.3. The same method is alsoapplied to the and Mg2 Lick indices for the samplegalaxies. The results obtained are [Ti/Fe]~[Mg/Fe]~+0.3, indicating aclear enhancement of the α-elements-to-iron ratio for our sampleof early-type galaxies. Based on observations in the Observatóriodo Pico dos Dias, operated by the Laboratório Nacional deAstrofísica/CNPq/MCT, Brazil.
| Spectral Irradiance Calibration in the Infrared. X. A Self-Consistent Radiometric All-Sky Network of Absolutely Calibrated Stellar Spectra
We start from our six absolutely calibrated continuous stellar spectrafrom 1.2 to 35 μm for K0, K1.5, K3, K5, and M0 giants. These wereconstructed as far as possible from actual observed spectral fragmentstaken from the ground, the Kuiper Airborne Observatory, and the IRAS LowResolution Spectrometer, and all have a common calibration pedigree.From these we spawn 422 calibrated ``spectral templates'' for stars withspectral types in the ranges G9.5-K3.5 III and K4.5-M0.5 III. Wenormalize each template by photometry for the individual stars usingpublished and/or newly secured near- and mid-infrared photometryobtained through fully characterized, absolutely calibrated,combinations of filter passband, detector radiance response, and meanterrestrial atmospheric transmission. These templates continue ourongoing effort to provide an all-sky network of absolutely calibrated,spectrally continuous, stellar standards for general infrared usage, allwith a common, traceable calibration heritage. The wavelength coverageis ideal for calibration of many existing and proposed ground-based,airborne, and satellite sensors, particularly low- tomoderate-resolution spectrometers. We analyze the statistics of probableuncertainties, in the normalization of these templates to actualphotometry, that quantify the confidence with which we can assert thatthese templates truly represent the individual stars. Each calibratedtemplate provides an angular diameter for that star. These radiometricangular diameters compare very favorably with those directly observedacross the range from 1.6 to 21 mas.
| Empirical calibration of the lambda 4000 Å break
Empirical fitting functions, describing the behaviour of the lambda 4000Ä break, D4000, in terms of effective temperature,metallicity and surface gravity, are presented. For this purpose, thebreak has been measured in 392 stars from the Lick/IDS Library. We havefollowed a very detailed error treatment in the reduction and fittingprocedures, allowing for a reliable estimation of the breakuncertainties. This calibration can be easily incorporated into stellarpopulation models to provide accurate predictions of the break amplitudefor, relatively old, composite systems. Table 1 is only available inelectronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr(130.79.128.5) or via http://cdsweb.u-strasbg.fr/Abstract.html
| Catalogs of temperatures and [Fe/H] averages for evolved G and K stars
A catalog of mean values of [Fe/H] for evolved G and K stars isdescribed. The zero point for the catalog entries has been establishedby using differential analyses. Literature sources for those entries areincluded in the catalog. The mean values are given with rms errors andnumbers of degrees of freedom, and a simple example of the use of thesestatistical data is given. For a number of the stars with entries in thecatalog, temperatures have been determined. A separate catalogcontaining those data is briefly described. Catalog only available atthe CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/Abstract.html
| H gamma and H delta Absorption Features in Stars and Stellar Populations
The H gamma and H delta absorption features are measured in a sample of455 (out of an original 460) Lick/IDS stars with pseudo--equivalentwidth indices. For each Balmer feature, two definitions, involving anarrow (~20 Angstroms) and a wide (~40 Angstroms) central bandpass, aremeasured. These four new Balmer indices augment 21 indices previouslydetermined by Worthey et al., and polynomial fitting functions that giveindex strengths as a function of stellar temperature, gravity, and[Fe/H] are provided. The new indices are folded into models for theintegrated light of stellar populations, and predictions are given forsingle-burst stellar populations of a variety of ages and metallicities.Contrary to our initial hopes, the indices cannot break a degeneracybetween burst age and burst strength in post-starburst objects, but theyare successful mean-age indicators when used with sensitive metallicityindicators. An appendix gives data, advice, and examples of how totransform new spectra to the 25-index Lick/IDS system.
| The photoelectric astrolabe catalogue of Yunnan Observatory (YPAC).
The positions of 53 FK5, 70 FK5 Extension and 486 GC stars are given forthe equator and equinox J2000.0 and for the mean observation epoch ofeach star. They are determined with the photoelectric astrolabe ofYunnan Observatory. The internal mean errors in right ascension anddeclination are +/- 0.046" and +/- 0.059", respectively. The meanobservation epoch is 1989.51.
| Ca II H and K Filter Photometry on the UVBY System. II. The Catalog of Observations
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1995AJ....109.2828T&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.
| Photometry of Stars in the Field of ZZ Draconis
Not Available
| Photometry for Stars in the Field of V Bootis
Not Available
| Old stellar populations. 5: Absorption feature indices for the complete LICK/IDS sample of stars
Twenty-one optical absorption features, 11 of which have been previouslydefined, are automatically measured in a sample of 460 stars. FollowingGorgas et al., the indices are summarized in fitting functions that giveindex strengths as functions of stellar temperature, gravity, and(Fe/H). This project was carried out with the purpose of predictingindex strengths in the integrated light of stellar populations ofdifferent ages and metallicities, but the data should be valuable forstellar studies in the Galaxy as well. Several of the new indices appearto be promising indicators of metallicity for old stellar populations. Acomplete list of index data and atmospheric parameters is available incomputer-readable form.
| The photometric variability of K giants
We have photometrically monitored 49 of the more than 200 K giants inthe Yale Catalog of Bright Stars (YCBS) which are named or suspectedvariable stars. Only two (HR 3275 and HR 5219) are clearly variable; afew more program stars and K- and M-giant comparison stars aremarginally variable. Most of these appear to be RS Canum Venaticorum orSR variables.
| The southern Vilnius photometric system. I - Transformation to the standard system
This paper is the first in a series on the extension of the Vilniusphotometric system to the southern hemisphere. Observations of a commonset of 73 stars measured in both hemispheres are described and ananalysis of the differences is given.
| A critical appraisal of published values of (Fe/H) for K II-IV stars
'Primary' (Fe/H) averages are presented for 373 evolved K stars ofluminosity classes II-IV and (Fe/H) values beween -0.9 and +0.21 dex.The data define a 'consensus' zero point with a precision of + or -0.018 dex and have rms errors per datum which are typically 0.08-0.16dex. The primary data base makes recalibration possible for the large(Fe/H) catalogs of Hansen and Kjaergaard (1971) and Brown et al. (1989).A set of (Fe/H) standard stars and a new DDO calibration are given whichhave rms of 0.07 dex or less for the standard star data. For normal Kgiants, CN-based values of (Fe/H) turn out to be more precise than manyhigh-dispersion results. Some zero-point errors in the latter are alsofound and new examples of continuum-placement problems appear. Thushigh-dispersion results are not invariably superior to photometricmetallicities. A review of high-dispersion and related work onsupermetallicity in K III-IV star is also given.
| A search for lithium-rich giant stars
Lithium abundances or upper limits have been determined for 644 brightG-K giant stars selected from the DDO photometric catalog. Two of thesegiants possess surface lithium abundances approaching the 'cosmic' valueof the interstellar medium and young main-sequence stars, and eight moregiants have Li contents far in excess of standard predictions. At leastsome of these Li-rich giants are shown to be evolved to the stage ofhaving convectively mixed envelopes, either from the direct evidence oflow surface carbon isotope ratios, or from the indirect evidence oftheir H-R diagram positions. Suggestions are given for the uniqueconditions that might have allowed these stars to produce or accrete newlithium for their surface layers, or simply to preserve from destructiontheir initial lithium contents. The lithium abundance of the remainingstars demonstrates that giants only very rarely meet the expectations ofstandard first dredge-up theories; the average extra Li destructionrequired is about 1.5 dex. The evolutionary states of these giants andtheir average masses are discussed briefly, and the Li distribution ofthe giants is compared to predictions of Galactic chemical evolution.
| Old stellar populations. II - an analysis of K-giant spectra
Eleven strong absorption features are studied in a sample of 110 K-giantstars, based on spectra taken at 9-A resolution, including such featuresas CN 4170 A, G-band, H-beta, Mg b, MgH, two Fe lines, NaD, and two TiObands. The surface features sensitive to surface gravity are determined;it is noted that the most accurate gravity indicator appears to be theindex Mg2. Previously identified super metal-rich stars generally showthe strongest lines of iron, CN, Mg, and NaD; essentially allintermediate and strong blends are also markedly enhanced in thesestars. Finally, iron-line residual Delta-Fe is shown to be a goodmeasure of metallicity and at the same time independent of surfacegravity.
| Carbon monoxide band intensities in M giants
The strength of CO (2.3 micron) bands was measured using the photometercomponent of the Kitt Peak 1.3-m telescope in an attempt to identifyextremely carbon-poor M giants. Magnitudes for about 200 bright M starswere obtained through a J filter, and narrow filters were centered on2.17 and 2.40 microns, respectively. No M giants were found with COindices indicative of extremely low carbon abundances. The correlationof CO index to effective temperature did not extend to the extremelylate and variable M giants. The dependence of CO index upon carbonabundance, 12-C/13-C ratio, surface gravity, effective temperature, andmicroturbulent velocity indices were also investigated. It is found thatthe predicted and observed CO indices are in good agreement for starswith spectroscopically determined carbon abundance.
| Narrow-Band and Broad-Band Photometry of Red Stars. III. Southern Giants
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1970ApJ...161..199E&db_key=AST
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Pozíciós és asztrometriai adatok
| Csillagkép: | Kígyó |
| Rektaszcenzió: | 15h18m26.20s |
| Deklináció: | -00°27'41.0" |
| Vizuális fényesség: | 5.89 |
| Távolság: | 300.3 parszek |
| RA sajátmozgás: | -10 |
| Dec sajátmozgás: | 0.8 |
| B-T magnitude: | 7.849 |
| V-T magnitude: | 6.041 |
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