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The Central Regions of M31 in the 3-5 μm Wavelength Region
Images obtained with NIRI on the Gemini North telescope are used toinvestigate the photometric properties of the central regions of M31 inthe 3-5 μm wavelength range. The light distribution in the centralarcsecond differs from what is seen in the near-infrared in the sensethat the difference in peak brightness between P1 and P2 is larger inM' than in K' no obvious signature of P3 isdetected in M'. These results can be explained if there is asource of emission that contributes ~20% of the peak M' lightof P1, has an effective temperature of no more than a few hundred K, andis located between P1 and P2. Based on the red K-M' color ofthis source, it is suggested that the emission originates in acircumstellar dust shell surrounding a single bright asymptotic giantbranch (AGB) star. Tests of this hypothesis are described. A brightsource that is ~8" from the center of the galaxy is also detected inM'. This object has red colors and an absolute brightness inM' that is similar to the most highly evolved AGB stars inthe solar neighborhood; hence, it is likely to be a very evolved AGBstar embedded in a circumstellar envelope. The K-band brightness of thisstar is close to the peak expected for AGB evolution, and an age of onlya few hundred million years is estimated, which is comparable to that ofthe P3 star cluster. Finally, using high angular resolutionnear-infrared adaptive optics images as a guide, a sample of unblendedAGB stars outside of the central few arcseconds is defined inL'. The (L', K-L') color-magnitudediagram of these sources shows a dominant AGB population with a peakL' brightness and a range of K-L' colors that aresimilar to those of the most luminous M giants in the Galactic bulge.Based on observations obtained at the Gemini Observatory, which isoperated by the Association of Universities for Research in Astronomy,Inc., under a cooperative agreement with the National Science Foundation(NSF) on behalf of the Gemini partnership: the NSF (United States), theParticle Physics and Astronomy Research Council (United Kingdom), theNational Research Council of Canada (Canada), CONICYT (Chile), theAustralian Research Council (Australia), CNPq (Brazil), and CONICET(Argentina).
| 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.
| 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
| Stars with the Largest Hipparcos Photometric Amplitudes
A list of the 2027 stars that have the largest photometric amplitudes inHipparcos Photometry shows that most variable stars are all Miras. Thepercentage of variable types change as a function of amplitude. Thiscompilation should also be of value to photometrists looking forrelatively unstudied, but large amplitude stars.
| 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.
| The 74th Special Name-list of Variable Stars
We present the Name-list introducing GCVS names for 3153 variable starsdiscovered by the Hipparcos mission.
| The PL relation of galactic carbon LPVs. The distance modulus to LMC
We present a period-luminosity (PL) diagram of 115 galactic carbon-richlong period variables (LPVs) observed by the HIPPARCOS satellite, in theform of the (MK,log P) relation. Our plot is compared to thediagram of carbon variables observed in the Large Magellanic Cloud(LMC). Both diagrams are found very similar and three samples aredelineated: long period variables close to the PL relation of Feast etal. (1989), short period-overluminous variables and a few underluminousLPVs, respectively Samples 1, 2 and 3. The used data were deduced fromexpectations of true parallaxes (Knapik et al. 1997) which arestatistically free of the Lutz-Kelker effect. The remaining bias due tothe non-gaussian distribution of absolute magnitudes is avoided: anon-linear parametric method is applied in Sect. 4 to the analysis ofthe PL relation for Sample 1 (72 LPVs). We obtainMK=(-3.99+/-0.13)log P+(2.07+/-0.15), in good agreement withthe slope found for LMC variables by Reid et al. (1995). The LMCdistance modulus then derived is mu =18.50+/-0.17. A well-defined upperlimit (ul) for long period stars in Sample 1 is found, with similarslopes in both the Galaxy (-4.85) and LMC (-4.72). No correction formetallicity was applied to the results. This research has made use ofthe Simbad database operated at CDS, Strasbourg, France.
| Classification and Identification of IRAS Sources with Low-Resolution Spectra
IRAS low-resolution spectra were extracted for 11,224 IRAS sources.These spectra were classified into astrophysical classes, based on thepresence of emission and absorption features and on the shape of thecontinuum. Counterparts of these IRAS sources in existing optical andinfrared catalogs are identified, and their optical spectral types arelisted if they are known. The correlations between thephotospheric/optical and circumstellar/infrared classification arediscussed.
| Optical and infrared observations of 23 carbon-rich stars. Modelling of the circumstellar dust shells.
A study of circumstellar dust shells (CDS) around carbon stars ispresented. This study is based on the analysis of the 1-100μmbroad-band spectra of 23 objects which have been monitored in the1-20μm region over several years at ESO. The sources in the samplerange from Irr/SR variables and optical miras to Extreme Carbon Starswhich have only been discovered recently in infrared surveys. Amodelling accounting for the photometric variations with phase (with upto 9 spectra per object) has been developed. All the CDSs in the samplecan be modelled successfully in spherical geometry with a dust opacitylaw {prop.to}λ^-1.3^ and a dust formation temperature ~950K. Themodelling favors the case of an acceleration of dust, from the site offormation and on a distance of ~10^15^cm, over the case of a uniformexpansion. Mass loss rates in the range 0.1-50x10^-6^Msun_/yrare derived. The estimates based on this modelling are consistent withthose derived from the CO emission line measurements. In view of theincoming near-infrared surveys (DENIS and 2MASS), an analysis of thelocation of carbon-rich sources in color diagrams is presented. It isshown that the near-infrared colors are well correlated with the massloss rate. This property can be used to get an estimate, within a factor3, of this rate for carbon stars without a priori on the distance.
| 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.
| 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.
| The evolution of galactic carbon stars.
Based on a comparison of observations with new synthetic AGB evolutioncalculations we propose a revised evolutionary scenario for carbon starsin the solar neighbourhood. From observations we derive that the lowestinitial mass from which carbon stars form is about 1.5Msun_.This constraint combined with four other constraints (the observedinitial-final mass relation, the birth rate of carbon stars, theobserved abundance ratios in planetary nebulae (PNe) and the numberratios C/M and S/C of AGB stars) are used to derive the followingparameters for the synthetic AGB evolution model. Third dredge-up occursfor core masses above 0.58Msun_ and the dredge-up efficiencyis λ=0.75. We consider a Reimers mass loss law (with a scalingfactor η_AGB_) and the mass loss rate law recently proposed byBloecker & Schoenberner (1993; with a scaling factor η_BS_). Wefind η_AGB_=4 and η_BS_=0.08. Both models fit the observationsequally well. The model predicts that stars in the range1.5Msun_<~M<~1.6Msun_ become carbon stars attheir last thermal pulse (TP) on the AGB and live only a few 10^4^yr ascarbon stars. More massive stars experience additional TPs as carbonstars (up to about 25 for a 3Msun_ star) and live up to10^6^yr. For M>4Msun_ hot-bottom burning prevents theformation of carbon stars. For M<~2Msun_, M-stars skip theS-star phase when they become carbon stars. The average lifetime of thecarbon star phase is ~3x10^5^yr. The carbon stars for which C/O ratioshave been derived in the literature (with values <~1.5) arepredominantly optical carbon stars with a 60μm excess. Yet, disk PNeare known with C/O ratios up to about 4. We predict that carbon starswith C/O ratios >1.5 are to be found among the infrared carbon stars.The model predicts that the probability that a carbon star hasC/O>1.5 is about 30%, in reasonable agreement with the observed ratioof the surface density in the galactic plane of infrared carbon stars toall carbon stars. The infrared carbon stars are predicted to be (onaverage) more massive than the optical carbon stars. The fact thatcarbon stars with C/O>1.5 apparently never reach the optical carbonstar phase (with a detached shell) is probably due to differences inevolution. If indeed infrared carbon stars are on average more massive(i.e. have larger core masses) than optical carbon stars, the interpulseperiod is shorter, and the increase in luminosity during the TP issmaller (due to the larger envelope mass). Both effects will decreasethe likelihood of a detached shell to occur. We predict that two-thirdsof all detached shells around optical carbon stars are oxygen-rich.
| 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
| Evolution from visual to infrared carbon stars: Interrupted mass-loss model
a set of self-consistent model calulations of the evolution from visualcarbon stars to infrared carbon stars is presented. A two-shell systemmodel, the interrurpted mass-loss model (oxygen-rich detached shell andnewly forming SiC dust shell), has been developed. This model overcomesthe shortcomings of the single detached-shell model (Chan and Kwok 1988)and the SiC shell model (Chan and Kwok 1990). A new mass-loss formula,which describes the gradually increasing mass-loss rate at the earlystage of the infrared carbon stars, is introduced to simulate the effectof the newly forming SiC shell. The model tracks successfully explain a'C' -shaped distribution of carbon stars in the color-color diagram. Theenergy distributions of approximately 110 transition objects are fittedwith devloping SiC dust shells using the interrupted mass-loss model.The existence of these transition objects with infrared propertiesintermediate between visual and infrared carbon stars, lends futhersupport to the idea of an evolutionary link between visual and infraredcabon stars.
| Identification of 106 new infrared carbon stars in the IRAS Point Source Catalog - Near-infrared photometry and their space distribution in the galaxy
A method based solely on IR colors - the combination of near-IR and IRAScolors - is used to identify 106 new IR carbon stars (IRCS). It is shownthat the proportion of IRCS in a region of the IRAS two-color diagrampreviously thought to contain the largest concentration of such stars isnot as large as expected for the faintest objects. A local spatialnumber density of about 12 IRCS/sq kpc is estimated. It is shown to beuniform within 5 to 11 kpc from the galactic center. The local ratio ofIRCS to optical carbon stars is found to be about 35 percent. A totalrestitution rate of about 10 to the -4 solar masses/yr/sq kpc isderived. The efficiency of the combination of near and mid-IR photometryfor the study of AGB stars is confirmed.
| Carbon-star lightcurves in the 1-20 micron range
The results of a photometric monitoring in the wavelength range 1-20microns are presented for 23 carbon-rich sources. The sample has beenselected to contain optically bright and dust enshrouded carbon stars.Using data obtained in the NIR periods are determined by Fourieranalysis for 19 sources; for the four remaining objects, there is noevidence of periodicity in the variations. The periods are found in therange 350-750 days. The longest period was obtained for AFGL 1085 (about725 days). The amplitudes of the variations from 1 to 20 microns areestimated by sine-fitting of the lightcurves. In general, the amplitudesdecrease with wavelength. Periods are only weakly correlated withamplitudes and colors, but amplitudes and colors are well correlatedtogether. In the sample of 19 periodic sources, there is no differencein the variability properties of optical carbon stars anddust-enshrouded carbon stars. In two cases (AFGL 1062 and AFGL 1085),there is a clear evidence in the lightcurves of a plateau on the risingbranches.
| On the nature of the excess 100 micron flux associated with carbon stars
The emission from carbon stars with circumstellar dust shells ofdifferent structure, composition, opacity, and age was modeled with thepurpose of determining the origin of the excess flux in the FIR andtesting the detached shell hypotheses of Willems (1987) and Olofsson etal. (1990). Three possible sources for the excess flux were identified:(1) cool dust in a single extended shell; (2) emission from dust in theintervening interstellar medium; or (3) emission from a two-shell systemin which the additional shell is a remnant from an earlier mass-lossepisode. It was found that only the two-shell model with a remnant shellwhich is at least 1 pc thick could explain the 60- and 100-micron fluxexcesses seen in carbon stars with dust shells of a given opacity.Calculations of time scales for the production of the detached shellsand of the carbon star lifetime were found to be consistent with theevolutionary scenario proposed by Willems.
| The mid-infrared spectrum of the carbon star HD 38218 and its possible relation to polycyclic aromatic hydrocarbons
The mid-infrared spectra of carbon giant stars with hot companions areinvestigated in order to search for infrared emission bands frompolycyclic aromatic hydrocarbons (PAH) in the envelopes of the C giants.A strong 8-micron emission band found in TU Tau = HD 38218 is attributedto the binary A star companion. It is argued that if the 8-micronfeature in HD 38218 arises from PAHs, they seem to be importantconstituents of the C-giant shell, and they might be large compared withsome interstellar PAHs. It is suggested that because no other IR spectraof C giants show clear PAH features, the greater flux of hard radiationin the binary HD 38218 seems likely to be responsible for the 8-micronfeature and for its absence in many other C giants. Thus, PAHs could bepresent in the same amounts relative to SiC grains in the shells ofsimilar single C giants, and the formation of carbonaceous grains couldproceed through the formation of PAHs in C giant shells.
| A general catalogue of cool carbon stars
Not Available
| 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.
| IRAS catalogues and atlases - Atlas of low-resolution spectra
Plots of all 5425 spectra in the IRAS catalogue of low-resolutionspectra are presented. The catalogue contains the average spectra ofmost IRAS poiont sources with 12 micron flux densities above 10 Jy.
| New UBVRI photometry for 900 supergiants
A description is presented of the results obtained in connection with asystematic program of supergiant photometry on the Johnson UBVRI system.During the eight years after the start of the program, almost 1000 starshave been observed, about 400 three or more times each. The originalselection of stars used the spectral type catalog of Jaschek et al.(1964) to choose supergiants. Since observations were possible from bothChile and Canada, no declination limits were imposed, and no particularselection criteria were imposed other than to eliminate carbon stars.These are so red as to require enormous extrapolations of thetransformation equations.
| Classification of 831 two-micron sky survey sources south of +5 degrees.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1975AJ.....80.1011H&db_key=AST
| The absolute magnitudes of carbon stars - Carbon stars in binary systems
Abstract image available at:http://adsabs.harvard.edu/abs/1975ApJ...200...88O
| A general catalogue of cool carbon stars
Not Available
| Carbon Stars with Composite Spectra.
Abstract image available at:http://adsabs.harvard.edu/abs/1972ApJ...172L..63R
| Some Intrinsic Properties of Carbon Stars
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1971ApJ...167..521R&db_key=AST
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| קבוצת-כוכבים: | כלב גדול |
| התרוממות ימנית: | 06h23m39.12s |
| סירוב: | -27°03'56.7" |
| גודל גלוי: | 8.725 |
| מרחק: | 1923.077 פארסק |
| תנועה נכונה: | 0.1 |
| תנועה נכונה: | -0.1 |
| B-T magnitude: | 12.37 |
| V-T magnitude: | 9.026 |
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