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Pulkovo compilation of radial velocities for 35495 stars in a common system.
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| Hipparcos red stars in the HpV_T2 and V I_C systems
For Hipparcos M, S, and C spectral type stars, we provide calibratedinstantaneous (epoch) Cousins V - I color indices using newly derivedHpV_T2 photometry. Three new sets of ground-based Cousins V I data havebeen obtained for more than 170 carbon and red M giants. These datasetsin combination with the published sources of V I photometry served toobtain the calibration curves linking Hipparcos/Tycho Hp-V_T2 with theCousins V - I index. In total, 321 carbon stars and 4464 M- and S-typestars have new V - I indices. The standard error of the mean V - I isabout 0.1 mag or better down to Hp~9 although it deteriorates rapidly atfainter magnitudes. These V - I indices can be used to verify thepublished Hipparcos V - I color indices. Thus, we have identified ahandful of new cases where, instead of the real target, a random fieldstar has been observed. A considerable fraction of the DMSA/C and DMSA/Vsolutions for red stars appear not to be warranted. Most likely suchspurious solutions may originate from usage of a heavily biased color inthe astrometric processing.Based on observations from the Hipparcos astrometric satellite operatedby the European Space Agency (ESA 1997).}\fnmsep\thanks{Table 7 is onlyavailable 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/qcat?J/A+A/397/997
| s-Process Nucleosynthesis in Carbon Stars
We present the first detailed and homogeneous analysis of the s-elementcontent in Galactic carbon stars of N type. Abundances of Sr, Y, Zr(low-mass s-elements, or ls), Ba, La, Nd, Sm, and Ce (high-masss-elements, or hs) are derived using the spectral synthesis techniquefrom high-resolution spectra. The N stars analyzed are of nearly solarmetallicity and show moderate s-element enhancements, similar to thosefound in S stars, but smaller than those found in the only previoussimilar study (Utsumi 1985), and also smaller than those found insupergiant post-asymptotic giant branch (post-AGB) stars. This is inagreement with the present understanding of the envelope s-elementenrichment in giant stars, which is increasing along the spectralsequence M-->MS-->S-->SC-->C during the AGB phase. Wecompare the observational data with recent s-process nucleosynthesismodels for different metallicities and stellar masses. Good agreement isobtained between low-mass AGB star models (M<~3 Msolar)and s-element observations. In low-mass AGB stars, the13C(α, n)16O reaction is the main source ofneutrons for the s-process a moderate spread, however, must exist in theabundance of 13C that is burnt in different stars. Bycombining information deriving from the detection of Tc, the infraredcolors, and the theoretical relations between stellar mass, metallicity,and the final C/O ratio, we conclude that most (or maybe all) of the Nstars studied in this work are intrinsic, thermally pulsing AGB stars;their abundances are the consequence of the operation of third dredge-upand are not to be ascribed to mass transfer in binary systems.
| Carbon-rich giants in the HR diagram and their luminosity function
The luminosity function (LF) of nearly 300 Galactic carbon giants isderived. Adding BaII giants and various related objects, about 370objects are located in the RGB and AGB portions of the theoretical HRdiagram. As intermediate steps, (1) bolometric corrections arecalibrated against selected intrinsic color indices; (2) the diagram ofphotometric coefficients 1/2 vs. astrometric trueparallaxes varpi are interpreted in terms of ranges of photosphericradii for every photometric group; (3) coefficients CR andCL for bias-free evaluation of mean photospheric radii andmean luminosities are computed. The LF of Galactic carbon giantsexhibits two maxima corresponding to the HC-stars of the thick disk andto the CV-stars of the old thin disk respectively. It is discussed andcompared to those of carbon stars in the Magellanic Clouds and Galacticbulge. The HC-part is similar to the LF of the Galactic bulge,reinforcing the idea that the Bulge and the thick disk are part of thesame dynamical component. The CV-part looks similar to the LF of theLarge Magellanic Cloud (LMC), but the former is wider due to thesubstantial errors on HIPPARCOS parallaxes. The obtained meanluminosities increase with increasing radii and decreasing effectivetemperatures, along the HC-CV sequence of photometric groups, except forHC0, the earliest one. This trend illustrates the RGB- and AGB-tracks oflow- and intermediate-mass stars for a range in metallicities. From acomparison with theoretical tracks in the HR diagram, the initial massesMi range from about 0.8 to 4.0 Msun for carbongiants, with possibly larger masses for a few extreme objects. A largerange of metallicities is likely, from metal-poor HC-stars classified asCH stars on the grounds of their spectra (a spheroidal component), tonear-solar compositions of many CV-stars. Technetium-rich carbon giantsare brighter than the lower limit Mbol =~ -3.6+/- 0.4 andcentered at =~-4.7+0.6-0.9 at about =~(2935+/-200) K or CV3-CV4 in our classification. Much like the resultsof Van Eck et al. (\cite{vaneck98}) for S stars, this confirms theTDU-model of those TP-AGB stars. This is not the case of the HC-stars inthe thick disk, with >~ 3400 K and>~ -3.4. The faint HC1 and HC2-stars( =~ -1.1+0.7-1.0) arefound slightly brighter than the BaII giants ( =~-0.3+/-1.3) on average. Most RCB variables and HdC stars range fromMbol =~ -1 to -4 against -0.2 to -2.4 for those of the threepopulation II Cepheids in the sample. The former stars show the largestluminosities ( <~ -4 at the highest effectivetemperatures (6500-7500 K), close to the Mbol =~ -5 value forthe hot LMC RCB-stars (W Men and HV 5637). A full discussion of theresults is postponed to a companion paper on pulsation modes andpulsation masses of carbon-rich long period variables (LPVs; Paper IV,present issue). This research has made use of the Simbad databaseoperated at CDS, Strasbourg, France. Partially based on data from theESA HIPPARCOS astrometry satellite. Table 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/390/967
| The 85Kr s-Process Branching and the Mass of Carbon Stars
We present new spectroscopic observations for a sample of C(N)-type redgiants. These objects belong to the class of asymptotic giant branchstars, experiencing thermal instabilities in the He-burning shell(thermal pulses). Mixing episodes called third dredge-up enrich thephotosphere with newly synthesized 12C in the He-rich zone,and this is the source of the high observed ratio between carbon andoxygen (C/O>=1 by number). Our spectroscopic abundance estimatesconfirm that, in agreement with the general understanding of the lateevolutionary stages of low- and intermediate-mass stars, carbonenrichment is accompanied by the appearance of s-process elements in thephotosphere. We discuss the details of the observations and of thederived abundances, focusing in particular on rubidium, a neutrondensity sensitive element, and on the s-elements Sr, Y, and Zr belongingto the first s-peak. The critical reaction branching at 85Kr,which determines the relative enrichment of the studied species, isdiscussed. Subsequently, we compare our data with recent models fors-processing in thermally pulsing asymptotic giant branch stars, atmetallicities relevant for our sample. A remarkable agreement betweenmodel predictions and observations is found. Thanks to the differentneutron density prevailing in low- and intermediate-mass stars,comparison with the models allows us to conclude that most C(N) starsare of low mass (M<~3 Msolar). We also analyze the12C/13C ratios measured, showing that most of themcannot be explained by canonical stellar models. We discuss how thisfact would require the operation of an ad hoc additional mixing,currently called cool bottom process, operating only in low-mass starsduring the first ascent of the red giant branch and, perhaps, alsoduring the asymptotic giant branch.
| Long period variable stars: galactic populations and infrared luminosity calibrations
In this paper HIPPARCOS astrometric and kinematic data are used tocalibrate both infrared luminosities and kinematical parameters of LongPeriod Variable stars (LPVs). Individual absolute K and IRAS 12 and 25luminosities of 800 LPVs are determined and made available in electronicform. The estimated mean kinematics is analyzed in terms of galacticpopulations. LPVs are found to belong to galactic populations rangingfrom the thin disk to the extended disk. An age range and a lower limitof the initial mass is given for stars of each population. A differenceof 1.3 mag in K for the upper limit of the Asymptotic Giant Branch isfound between the disk and old disk galactic populations, confirming itsdependence on the mass in the main sequence. LPVs with a thin envelopeare distinguished using the estimated mean IRAS luminosities. The levelof attraction (in the classification sense) of each group for the usualclassifying parameters of LPVs (variability and spectral types) isexamined. Table 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/374/968 or via ASTRIDdatabase (http://astrid.graal.univ-montp2.fr).
| The effective temperatures of carbon-rich stars
We evaluate effective temperatures of 390 carbon-rich stars. Theinterstellar extinction on their lines of sights was determined andcircumstellar contributions derived. The intrinsic (dereddened) spectralenergy distributions (SEDs) are classified into 14 photometric groups(HCi, CVj and SCV with i=0,5 and j=1,7). The newscale of effective temperatures proposed here is calibrated on the 54angular diameters (measured on 52 stars) available at present from lunaroccultations and interferometry. The brightness distribution on stellardiscs and its influence on diameter evaluations are discussed. Theeffective temperatures directly deduced from those diameters correlatewith the classification into photometric groups, despite the large errorbars on diameters. The main parameter of our photometric classificationis thus effective temperature. Our photometric < k right >1/2 coefficients are shown to be angular diameters on arelative scale for a given photometric group, (more precisely for agiven effective temperature). The angular diameters are consistent withthe photometric data previously shown to be consistent with the trueparallaxes from HIPPARCOS observations (Knapik, et al. \cite{knapik98},Sect. 6). Provisional effective temperatures, as constrained by asuccessful comparison of dereddened SEDs from observations to modelatmosphere predictions, are in good agreement with the values directlycalculated from the observed angular diameters and with those deducedfrom five selected intrinsic color indices. These three approaches wereused to calibrate a reference angular diameter Phi 0 and theassociated coefficient CT_eff. The effective temperatureproposed for each star is the arithmetic mean of two estimates, one(``bolometric'') from a reference integrated flux F0, theother (``spectral'') from calibrated color indices which arerepresentative of SED shapes. Effective temperatures for about 390carbon stars are provided on this new homogeneous scale, together withvalues for some stars classified with oxygen-type SEDs with a total of438 SEDs (410 stars) studied. Apparent bolometric magnitudes are given.Objects with strong infrared excesses and optically thick circumstellardust shells are discussed separately. The new effective temperaturescale is shown to be compatible and (statistically) consistent with thesample of direct values from the observed angular diameters. Theeffective temperatures are confirmed to be higher than the mean colortemperatures (from 140 to 440 K). They are in good agreement with thepublished estimates from the infrared flux method forTeff>= 3170 K, while an increasing discrepancy is observedtoward lower temperatures. As an illustration of the efficiency of thephotometric classification and effective temperature scale, the C/Oratios and the Merrill-Sanford (M-S) band intensities are investigated.It is shown that the maximum value, mean value and dispersion of C/Oincrease along the photometric CV-sequence, i.e. with decreasingeffective temperature. The M-S bands of SiC2 are shown tohave a transition from ``none'' to ``strong'' at Teff =~(2800+/- 150right ) K. Simultaneously, with decreasing effectivetemperature, the mean C/O ratio increases from 1.04 to 1.36, thetransition in SiC2 strength occurring while 1.07<= C/O<= 1.18. This research has made use of the Simbad database operatedat CDS, Strasbourg, France. Table 10 is only available in electronicform at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5)}or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/369/178
| General Catalog of Galactic Carbon Stars by C. B. Stephenson. Third Edition
The catalog is an updated and revised version of Stephenson's Catalogueof Galactic Cool Carbon Stars (2nd edition). It includes 6891 entries.For each star the following information is given: equatorial (2000.0)and galactic coordinates, blue, visual and infrared magnitudes, spectralclassification, references, designations in the most significantcatalogs and coordinate precision classes. The main catalog issupplemented by remarks containing information for which there was noplace in entries of the main part, as well as some occasional notesabout the peculiarities of specific stars.
| Interstellar extinction and the intrinsic spectral distribution of variable carbon stars.
We present a new method of evaluation of the extinction by interstellardust on cool carbon variables. These late-type stars show no markedrelationship between spectral classification (the R, N- and C-types) andphotometric colour indices. The pair method is thus ruled out, at leastin the form currently in use for early-type or intermediate stars. Ourmethod makes use of the whole spectral energy distributions from UV toIR. A sample of 60 unreddened carbon variables is delineated and newcolour-colour diagrams are proposed where the reddening vector is nearlyperpendicular to their narrow intrinsic locus. Six photometric groups(or boxes : CV1 to 6) are derived among unreddened stars. They show acontinuous range of spectral energy distributions from "bluer" to"redder", and mean colour indices are obtained. A pair method isdescribed where each presumably reddened star is compared to these meanunreddened stars, a given extinction law being assumed. As anillustration, the results are shown for a sample of 133 well-documentedstars. The mean extinction law usually adopted for the diffuseinterstellar medium (R_V_=~3.1) is shown to provide good fits. Thethreshold for reddening detection turns to be E(B-V)=~0.02-0.03A goodcorrelation is observed when the derived colour excesses are compared tovalues from maps in the literature. The mean rate of visual extinctionamounts to =~1.25+/-1.1 , ranging from 0.37 nearl=~240° (intercloud) to 2.1 (cloud + intercloud) in two structurescorrelated with Gould's belt.
| Quantitative analysis of carbon isotopic ratios in carbon stars. I. 62 N-type and 15 SC-type carbon stars.
We present a result of quantitative analysis of ^12^C/^13^C ratios in 62N-type and 15 SC-type carbon stars. By the use of CCD as a detector wecan obtain spectra of resolution ~20,000 with enough signal-to-noiseratios for a large number of carbon stars, for which ^12^C/^13^C ratioshave not yet been derived. Carbon isotopic ratios are determined fromlines of the CN red system around 8000A, based on the iso-intensitymethod and line-blanketed model atmospheres. The average of ^12^C/^13^Cratios in 62 N-type carbon stars is found to be 27+/-11 (standarddeviation). The majority of the N-type carbon stars studied (about 85%)are found to have ^12^C/^13^C ratios less than 40, and the number ofstars which have ^12^C/^13^C ratios larger than 40 is found to berelatively small. This result shows a marked contrast to some of theprevious results that have shown the opposite distribution, namely,^12^C/^13^C ratios mostly larger than 40 in N-type carbon stars. Theaverage of ^12^C/^13^C ratios in 15 SC-type carbon stars is found to be22+/-14 (standard deviation). Most of the SC-type carbon stars studiedare found to have ^12^C/^13^C ratios larger than 10, while only three ofthem turn out to be ^13^C-rich. This is in contrast with the earlierclassification based on low resolution spectra which classified them asJ-type, that is, ^13^C-rich. The earlier temperature scale whichclassified SC-type carbon stars as the latest (C8-9) based on theirstrong NaI D lines can not be necessarily justified. The strong NaI Dlines of SC stars should be attributed to the peculiar atmosphericstructure due to C/O ratios very near to unity. The resulting^12^C/^13^C ratios are partly consistent with the scenario in which Mgiants evolve through SC-type to N-type carbon stars, as ^12^C producedduring the helium shell flash is added to the envelope.
| 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 B jRI Photometric System
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1995ApJS...99..281G&db_key=AST
| A Catalog of li Abundances and Equivalent Widths in a Sample of Galactic C-Stars
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1993A&AS..102..361B&db_key=AST
| A Study of Circumstellar Envelopes around Bright Carbon Stars. II. Molecular Abundances
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1993ApJS...87..305O&db_key=AST
| The radio properties of high-redshift quasars. I - Dual-frequency observations of 79 steep-spectrum quasars at Z over 1.5
We have made sensitive VLA observations of virtually all knownhigh-redshift radio-loud QSOs with extended radio morphologies. Theresulting images have angular resolutions of typically 0.4 and 0.15arcsec and are compiled here. This compilation of maps will permit theextraction of numerous radio source parameters, constituting a data basefor comprehensive statistical analyses to be explored in subsequentpapers. The data base is particularly useful for statistical studies.The key characteristics of the sample are the narrow redshift range, thenarrow distribution in linear resolutions of the maps, the narrowdistribution of map sensitivity to emitting regions of standard physicalcharacteristics, and the relatively narrow range of source luminosities.As a result of these properties, the sample enjoys relative freedom fromthe effects of parameter correlations with redshift and luminosity. Abrief discussion of the sample characteristics and some elaboration ofthe particular advantages of this sample are presented. Some cleartrends in the data are discussed briefly.
| The determination of C/O and 12C/13C ratios from molecular indices in the atmospheres of the carbon stars.
Not Available
| A search for cool carbon stars. IV - Serpens-Aquila-Scutum (l of about 30 deg) region
A search for cool carbon stars has been consecutively made using the4-deg prism spectra of the Kiso 105-cm Schmidt telescope. The surveyedarea in this paper is the 240 square-degree area in theSerpens-Aquila-Scutum region. The celestial position, V magnitude, andthe finding chart of 60 cool carbon stars derived from V-band plates arepresented. Among the detected objects, 28 stars are not listed inStephenson's (1973, 1985) general catalog of carbon stars. Thevariability and the distribution of cool carbon stars are brieflydiscussed.
| The 77-81 intermediate-band photometric system
The 77-81 intermediate-band photometric color system for the study oflate-type stars is defined. The passbands are centered on a region ofTiO absorption at 7750 A (77) and on a region of CN absorption at 8100 A(81). Good agreement is found between measurements made on the 77-81system with different detectors. The 77-81 color is well correlated withM type and reasonably correlated with carbon-richness class. The 77-81,V-I color-color diagram clearly distinguishes M and C types from otherstars. It is also shown that the 77-81 color may be used to measure TiOband strength.
| A general catalogue of cool carbon stars
Not Available
| SEST CO (J = 1 - 0) observations of carbon-rich circumstellar envelopes
The authors have used the Swedish ESO Submillimetre Telescope (SEST) tosearch for circumstellar CO (J = 1-0) emission towards bright carbonstars in the southern hemisphere. A correlation between the estimatedmass loss rate and a far-IR excess measure is discussed. The CO (1-0)line profiles indicate a diversity in the characteristics of thecircumstellar envelopes. In particular, two stars with distinctlydouble-peaked line shapes have been detected. One of them, S Sct, isinterpreted in terms of an extended, cold, detached shell, with no hotgas/dust close to the star.
| A flux-limited sample of Galactic carbon stars
Published observational data (including IRAS observations) for aflux-limited sample of 215 Galactic carbon stars (CSs) selected from the2-micron sky survey of Neugebauer and Leighton (1969) are compiled inextensive tables and graphs and analyzed statistically. The sample isfound to penetrate a volume of radius 1.5 kpc, and the local CS spacedensity and surface density are calculated as log rho0 (per cu kpc) =2.0 + or - 0.4 and log N (per sq kpc) = 1.6 + or - 0.2, respectively.The total Galactic mass-return rate from these CSs is estimated as 0.013solar mass/yr, implying a time scale of 0.1-1 Myr for the CSevolutionary phase and a mass of 1.2-1.6 solar mass for the (probablyF-type) main-seqence progenitors of CSs.
| Low Temperature Carbon Stars in the Vilnius Photometric System - Part Two
Not Available
| The stellar component of the galaxy as seen by the AFGL infrared sky survey
The noise-limited magnitudes for the Air Force Geophysical Laboratory(AFGL) Infrared Sky Survey have been estimated by direct comparison withground-based observations. Using these limiting magnitudes, 'pruned'versions of the AFGL catalog have been generated. Infrared observationsof all the stellar objects seen at 11, 20, or 27 microns and astatistical sample of the stars seen only at 4 microns are reported.Analysis of the observations leads to estimates of the absolute 4 and 10microns magnitudes and space densities for the two clases of objects.The expected results from the Infrared Astronomical Satellite arereexamined.
| Suggested Identifications for Infrared Sources
Not Available
| A Search for Carbon Stars in the AFGL Catalogue
A comparison between the General Catalogue of Cool Carbon Stars (CCS)and the AFGL Catalogue has been performed. Eighty-five stars have beenfound in common between the two lists. Eighty-four stars which werepresent in Baumert's comparison between CCS and the 2 ~ Sky Survey haveno counterpart in the AFGL. Four new tentative identifications aregiven. The analysis of the two colours diagrams K-[4.2 p~ vs. I-K andI-[4.2 ~ vs. [4.2 ~]-[11 ~t] led to the conclusion that all the infraredemission from the sources seems to come from a single circumstellarshell
| Infrared photometry of galactic carbon stars
Infrared photometry in the JHKL bands is presented for 25 SRb and Lbgalactic carbon stars. Bolometric corrections and intrinsic colors aredetermined; two stars are found to have infrared excesses at 2.2 and 3.4microns. Comparisons are made with previous estimates of Mbol and therange of possible values is discussed.
| Photometry and Radial Velocities of Southern Carbon Stars
Not Available
| The distances of nearby cool carbon stars
Distance ratios are provided for 38 cool carbon stars on the basis of aprevious study (Bergeat et al., 1976). The validation of this distancescale is obtained through an analysis of stellar velocities. Arelationship is established between proper motions and the distancescale. Luminosities and radii are derived for cool carbon stars whichpermit a discussion of their evolutionary status. Finally, evaluationsare given for the rate of mass ejection corresponding to large graphitegrains.
| Spectrophotometry of cool carbon stars
Observations of 75 carbon stars have been made with the Indiana rapidspectrum scanner covering a wavelength range of 5000 A-7000 A at 30-Aresolution. The data have been used to form molecular indices for aquantitative measurement of the strength of the C2 Swan system and theshape of the CN red (6, 1) band sequence which is sensitive to theC-12/C-13 isotope ratio. The C2 strength is plotted against the strengthof CN and CO; the observed band strengths are found to behave as wouldbe expected from model-atmosphere calculations. Using C/O ratios fromKilston (1975) it is possible to calculate the observed CN/C2 ratio anddetermine photometric C/O ratios for 61 cool carbon stars. The CN red(6, 1) band photometry shows that only a few (25%) of cool carbon starshave C-12/C-13 isotope ratios significantly lower than the majority ofcool carbon stars.
| Magnetic fields and diffusion processes in peculiar A stars. II - Precession and the oblique rotator model
A global view of magnetic-field structure as it pertains to the natureand general properties of the phenomenon of spectrum variability ofpeculiar A stars is formulated in the context of the magnetic diffusionmechanism. Arguments relating to the stability of starspots are given interms of the magnetic field and rotation. Some observational tests aresuggested. The magnetic field is shown to cause departures of the starfrom sphericity, and this results in long-term free-body precession forAp stars of the shortest rotational periods. The effect of a closecompanion on such a star is examined briefly. Observed consequences andproblems are discussed.
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