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Infrared Study of J-Type Carbon Stars Based on Infrared Astronomical Satellite, Two Micron All Sky Survey, and Infrared Space Observatory Data
We collected 113 J-type carbon stars from the published literature.Observations from 2MASS, IRAS, and ISO show that, except for silicatecarbon stars in the J-type carbon star domain, the infrared propertiesof the other J-type carbon stars are quite similar to those of ordinarycarbon stars. The above results imply that the chemical peculiarity ofenhanced 13C for J-type carbon stars is not reflected in theinfrared region. In addition, the possible evolutionary scenario andbinarity for J-type carbon stars are also discussed.
| JHKLM Photometry for Carbon Stars
We discuss our JHKLM photometry for nine carbon Mira stars, eighteencarbon semiregular variables, and two oxygen Mira stars. For fourteencarbon stars, we present and analyze their infrared light and colorcurves. For all of the observed objects, we have estimated the opticaldepths of the circumstellar dust envelopes, the angular diameters of thestars, and their temperatures.
| J-type carbon stars in the Large Magellanic Cloud
A sample of 1497 carbon stars in the Large Magellanic Cloud (LMC) hasbeen observed in the red part of the spectrum with the 2dF facility onthe Anglo-Australian Telescope. Of these, 156 have been identified asJ-type (i.e. 13C-rich) carbon stars using a technique whichprovides a clear distinction between J stars and the normal N-typecarbon stars that comprise the bulk of the sample, and yields fewborderline cases. A simple two-dimensional classification of thespectra, based on their spectral slopes in different wavelength regions,has been constructed and found to be related to the more conventional cand j indices, modified to suit the spectral regions observed. Most ofthe J stars form a photometric sequence in the K- (J-K) colour-magnitudediagram, parallel to and 0.6 mag fainter than the N-star sequence. Asubset of the J stars (about 13 per cent) are brighter than this J-starsequence; most of these are spectroscopically different from the other Jstars. The bright J stars have stronger CN bands than the other J starsand are found strongly concentrated in the central regions of the LMC.Most of the rather few stars in common with Hartwick and Cowley's sampleof suspected CH stars are J stars. Overall, the proportion of carbonstars identified as J stars is somewhat lower than has been found in theGalaxy. The Na D lines are weaker in the LMC J stars than in either theGalactic J stars or the LMC N stars, and do not seem to depend ontemperature.
| 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
| 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
| New periodic variables from the Hipparcos epoch photometry
Two selection statistics are used to extract new candidate periodicvariables from the epoch photometry of the Hipparcos catalogue. Theprimary selection criterion is a signal-to-noise ratio. The dependenceof this statistic on the number of observations is calibrated usingabout 30000 randomly permuted Hipparcos data sets. A significance levelof 0.1 per cent is used to extract a first batch of candidate variables.The second criterion requires that the optimal frequency be unaffectedif the data are de-trended by low-order polynomials. We find 2675 newcandidate periodic variables, of which the majority (2082) are from theHipparcos`unsolved' variables. Potential problems with theinterpretation of the data (e.g. aliasing) are discussed.
| 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.
| Coordinates and Identifications for Sonneberg Variables on MVS 308-316
Not Available
| Quantitative analysis of carbon isotopic ratios in carbon stars. III. 26 J-type carbon stars including 5 silicate carbon stars
We present the result of a quantitative analysis of (12C/({13)) C}ratios in 26 J-type carbon stars. The (12C/({13)) C} ratios aredetermined from lines of the CN red system around 8000 Angstroms, usingthe iso-intensity method and line-blanketed model atmospheres. Theaverage of (12C/({13)) C}\ ratios in the 26 stars is 4.7 +/- 2.8(standard deviation). All the stars studied, except for two stars, have(12C/({13)) C}\ ratios smaller than 10. (12C/({13)) C}\ ratios as low as1 ~ 2, which are lower than the value at the equilibrium of theCN-cycle, are found for a significant fraction of our sample, suggestingthe operation of non-equilibrium nuclear processes. For several starspreviously analyzed by other authors, our result shows fair agreement.The serious disagreement of (12C/({13)) C}\ ratios, which we reportedfor N-type carbon stars in our preceding paper, is not found for J-typecarbon stars. Five silicate carbon stars in our sample show no peculiar(12C/({13)) C} ratios among the stars studied in the present work. Thisresult implies that the mechanism responsible for low (12C/({13)) C}\ratios in silicate carbon stars might be the same with that operating inother J-type carbon stars. In other words, (12C/({13)) C}\ ratios insilicate carbon stars have turned out to give few clues to identify themechanism responsible for their formation.
| The R Stars: Carbon Stars of a Different Kind
After $\sim$16 years of radial-velocity observations of a sample of 22R-type carbon stars, no evidence for binary motion has been detected inany of them. This is surprising considering that approximately 20\% ofnormal late-type giants are spectroscopic binaries, and the fraction isclose to 100\% in barium, CH, and subgiant/dwarf CH and barium stars. Itis suggested, therefore, that a process that has caused the mixing ofcarbon to the surface of these stars cannot act in a wide binary system.Possibly, the R stars were once all binaries, but with separations thatwould not allow them to evolve completely up the giant and asymptoticgiant branchs without coalescing. This coalescence may be the agentwhich causes carbon produced in the helium-core flash to be mixedoutwards to a region where convection zones can bring it to the surfaceof the star. (SECTION: Stars)
| Irregular variables of type Lb. New JHKL'M-photometry for 160 stars.
This paper presents new near infrared observations of 160 Irregularvariables of type Lb in the JHKL'M filter bands. These measurements aresupplemented by data for additional 56 stars taken from the literature.In total 220 datasets are available because of some multipleobservations. From our sample, 216 stars have near infrared (NIR)photometry now. Our sample of visually bright Lb-variables displays verysimilar infrared properties when compared with SRa- and SRb-variables.Derived from NIR-two colour diagrams the oxygen-rich Lbs seem to haveintermediate atmospheric conditions between Miras and normal giants.There may be a sligthly larger "contamination" with non AGB-giants thanin the case of the semiregulars. Using only our IR-colours the S- andthe Carbon-stars among the Lbs again are undistinguishable fromSR-variables of the same chemistry.
| A Moderate-Resolution Spectral Atlas of Carbon Stars: R, J, N, CH, and Barium Stars
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1996ApJS..105..419B&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.
| Photoelectric photometry of carbon stars in the Vilnius system
A total of 368 observations of magnitudes and color indices of 178carbon stars in the Vilnius seven-color photometric system are given.The observations are presented in a catalog.
| A general catalogue of cool carbon stars
Not Available
| Spectrophotometric investigation of carbon stars
Not Available
| The absolute spectrophotometry of carbon stars. VI. Abundance of carbon in the atmospheres.
Not Available
| Photoelectric photometry of carbon and barium stars in the Vilnius seven-color system and their color excesses
Not Available
| The absolute spectrophotometry of 18 carbon stars, III
Not Available
| Incidence of heavy element enhancements among carbon stars
The correlation of spectral line strength with temperature subclass hasbeen examined in a survey of 40 carbon stars at a dispersion of 15 A/mm.The two goals of this search were: (1) to determine if additional coolN-type stars can be added to the list of N stars not having enhanceds-process elements; and (2) to confirm the anticorrelation of s-processenhancements with C-13 enhancement. Among the program stars one normalcarbon star was found to have no, or only minor, enhancement of heavyelements associated with the s-process. The suspicion that increasedsurface C-13 is accompanied by weak line strengths of s-process elementsis strongly confirmed.
| Distances and luminosities of irregular variables of type N
Near-IR photometric data obtained by Baumert (1972) are presented for asubgroup of 107 irregular and semirregular N variables, and it issuggested that variations in the (0.78-1.08)-micron color indices ofthese stars are primarily due to interstellar reddening. On this basis,the distances of 60 stars are estimated from color excesses in (B - V),and luminosities are derived from photometric data relative to Vega andthe observed flux distribution to 14 microns from 19 Psc, which is takenas a prototype N irregular star. The estimated distances are shown to besupported by the Oort double-sine distribution of radial velocities, anapparent association with galactic spiral features, and agreement withprevious bolometric corrections. A dispersion in bolometric magnitude isfound in a Keenan-Morgan C subclass, with that parameter increasing froman average value of -4.4 in C4 stars to an average value of -5.6 in C7stars. Near-IR CN bands are found not to correlate with luminosity,while the Merrill-Sanford bands are found to be negative luminosityindicators.
| A general catalogue of cool carbon stars
Not Available
| Carbon Stars with Strong C^{13} and Lithium Spectral Features
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1971PASP...83..667G&db_key=AST
| A Brightening of the Ultraviolet Spectrum of the Carbon Star HD 59643
Abstract image available at:http://adsabs.harvard.edu/abs/1971ApJ...163..309G
| Catalog of Indidual Radial Velocities, 0h-12h, Measured by Astronomers of the Mount Wilson Observatory
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1970ApJS...19..387A&db_key=AST
| Objective Prism Spectra in the Near Infrared.
Abstract image available at:http://adsabs.harvard.edu/abs/1964ApJ...139..190N
| The magnitudes, colors and motions of stars of spectral class R.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1958AJ.....63..477V&db_key=AST
| Carbon Stars at Intermediate Galactic Latitudes.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1958ApJ...127..191B&db_key=AST
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