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Публикации по объекту
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.
| Pulkovo compilation of radial velocities for 35495 stars in a common system.
Not Available
| 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
| SiO maser survey of AGB stars in the North Galactic Cap
A SiO maser survey in the J=1-0, v=1 and 2 transitions has been made forIRAS sources in the North Galactic Cap b > 30o) with theNobeyama 45 m radio telescope. The sources were selected on the basis oftheir IRAS 12/25-μm and 25/60-μm flux ratios as likely oxygen-richAGB candidates. SiO masers were detected from 24 out of the 97 selectedsources, where 17 were new detections. The distances and heights abovethe Galactic plane are calculated. The Galactic distribution of detectedand undetected stars indicates that metallicity is likely to govern thedetection rate. The Galactocentric angular velocities of the subsampledstars are derived and their variation with the Galactic height isdiscussed. Based on observations at the Nobeyama Radio Observatory(NRO). NRO is a branch of the National Astronomical Observatory, aninter-university research institute, operated by the Ministry ofEducation, Science and Culture, Japan.
| 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.
| IRAS 12311-3509: a carbon star with SiC2 emission
The optical spectrum of the carbon star IRAS 12311-3509 is dominated bythe Merrill-Sanford emission bands of SiC2, by absorption andemission in the Swan system of C2, and by resonance emissionlines of neutral metals. The infrared energy distribution is flat from 1to 60μm. These observations are interpreted as arising from a starwith a cool dusty disc which is edge-on to the observer and obscuresdirect starlight. The infrared continuum is caused predominantly byabsorption of stellar light by dust in the disc and re-emission atlonger wavelengths. The optical stellar spectrum is seen by reflectionoff dusty material which lies out of the plane of the disc, and themolecular and atomic emission arises in the same geometry throughresonance fluorescence. The object has similarities to the J-silicatestars, but may have a carbon-rich rather than oxygen-rich disc. A fullspectroscopic assignment and discussion of the SiC2 bands andtheir intensities are given. Modelling of the rotational contours of the000 band yields a rotational temperature of 250K,indicating very cool gas.
| Dust extinction and intrinsic SEDs of carbon-rich stars. III. The Miras, CS, and SC stars
The present work is an extension of a recent study by Knapik &Bergeat (\cite{knapik97}), and Bergeat et al. (\cite{berge98b})henceforth called Papers I and II, respectively. The spectral energydistributions (SEDs) of about 440 carbon-rich stars and the interstellarextinction observed on their line of sights were analysed. The methodsoriginally developed for Semi-Regular (SR) and Irregular (L) variables(Paper I: our groups CV1 to CV6) were then extended (Paper II) to thehot carbon (HC) stars (our groups HC0 to HC5) and related objects (RCB,BaII and HdC stars). Shortly, this is a kind of a pair method making usesimultaneously of the whole SED from UV to IR. Our approach is appliedhere to the galactic cool carbon-rich variables which were notconsidered in Paper I, namely the carbon Miras and very cool non-Miras,and the CS and SC variables. The carbon Miras with infrared silicateemission are also studied. The photometric CV1 to CV6 classificationscheme of paper I is implemented, and we add here a later CV7-group anda specific SCV-group which corresponds to spectroscopic SC stars. Acontinuous S-SC-CS-C sequence is clearly supported by our results. Thecarbon stars with IR silicate emission included in our study do havecarbon-rich SEDs of the three consecutive groups HC5, CV1 and CV2. Theystand among the relatively hot carbon variables, in the 3600-3000 Krange in effective temperature. The carbon Miras are satisfactorilydescribed in this enlarged scheme. No specific extension is requiredsince non-Miras are also found in the CV7 and SCV-groups. The derivedgroup is however frequently phase-dependent in these large amplitudevariables. Additional selective extinction of circumstellar (CS) originis observed in variable amounts. The mean extinction law for theinterstellar diffuse medium as tabulated by Mathis (\cite{mathis}) isshown to be relevant. It applies to both interstellar and circumstellarextinction with a possible CS neutral extinction in addition which wouldremain undetected here. The corresponding colour excess E(B-V) is largerat minimum light or intermediate phases than what it is at maximum light(where it can amount to zero). It is associated to large IR excessesattributed to the emission from CS dust. Long-term variations onthousands of days may be interpreted in terms of varying CS dust opacityon the line of sight. The dust influence is discussed. It is shown thatscattering, if substantial on the line of sight in the observing lobe,has to be essentially wavelength-independent, i.e. due to large neutralscatterers, especially in high opacity objects like IRC +10216. Finally,with the HC0 to HC5 classification of HC stars (Paper II), we obtain afourteen groups sequence (HC0 to HC5 and then CV1 to CV7 from theearlier one to the latest one, and SCV for SC stars apart). The numberof studied stars amounts now to about 600 that is about 40 stars pergroup on the average when the oxygen-type SEDs are subtracted. Theeffective temperature calibration of this classification scheme iscurrently in preparation. This research has made use of the Simbaddatabase operated at CDS, Strasbourg, France.}\fnmsep\thanks{Partiallybased on data from the ESA HIPPARCOS astrometrysatellite}\fnmsep\thanks{Table~5 is only available in electronic form atthe CDS via anonymous ftp 130.79.128.5
| Dust extinction and intrinsic SEDs of carbon-rich stars. II. The hot carbon stars
The present work is an extension of a recent study by Knapik &Bergeat (\cite{knapik}, henceforth called Paper I) of the spectralenergy distributions (SEDs) of about 300 cool carbon-rich variables andof the interstellar extinction observed on their line of sights. Themethods were originally developed for Semi-Regular (SR) and Irregular(L)-variables. Shortly, this is a kind of a pair method making usesimultaneously of the whole SED from UV to IR. Our approach is appliedhere to the galactic carbon-rich giants with bluer SEDs, namely the hotcarbon (HC) stars, including many ``constant'' stars and a minority ofvariables: AC Her a RV Tau star, the R Coronae Borealis (RCB) stars andothers. Some HdC (i.e. carbon-rich hydrogen deficient stars) and Ba IIstars are also considered. The total number of studied HC stars amountsto about 140. With few exceptions, the colour excesses for interstellarextinction are found in good agreement with the field values from mapspublished in the literature, taking into account the approximatedistances to our stars from HIPPARCOS data (\cite{esa}, henceforthcalled ESA) or binarity. We propose a classification scheme with sixphotometric groups (or boxes: HC0 to HC5) from the bluest to the reddestSEDs. Oxygen-rich SEDs earlier than HC0, are attributed to the hotteststars (AC Her, most RCB-variables and a few others). Previous findingsare confirmed of a junction between oxygen-rich and carbon-rich SEDs atspectral type G. The latest (HC5) group is immediately close to theearliest one in Paper I, namely CV1. The sequence of groups then goesregularly from HC0 to CV6. Substantial infrared excesses with respect toour solutions are found in HD 100764 a HC1 carbon star, AC Her a G0g RVTau star, and the RCB stars classified in either HC or oxygen-groups.The colour excesses at maximum light can usually be attributed tointerstellar reddening, with neutral circumstellar (CS) reddening (largegrains) or no CS extinction at all on the line of sight (non sphericalgeometry) as possible explanations. The latter model (disc or patchydistribution through successive puffs) is favoured. Two RCB variablesfor which we exploit SEDs on a rising branch (V CrA) or minimum light(RS Tel), show CS laws, respectively a selective extinction compatiblewith small grains and an extinction partly neutral indicative of largegrains on the line of sight. This research has made use of the Simbaddatabase operated at CDS, Strasbourg, France.}\fnmsep\thanks{Partiallybased on data from the ESA HIPPARCOS astrometrysatellite}\fnmsep\thanks{Tables~3 and 4 are only available in electronicform at the CDS via anonymous ftp 130.79.128.5
| The 74th Special Name-list of Variable Stars
We present the Name-list introducing GCVS names for 3153 variable starsdiscovered by the Hipparcos mission.
| A further identification of silicate carbon stars.
The cross reidentifications of 22 silicate carbon stars are made byusing the GCGCS, IRAS PSC, HST GSC and USNO catalogues. More precisepositions of all sources refered are given for further study, and somesources doubted to be silicate carbon stars are also discussed.
| Infrared observation and energy distribution of silicate carbon stars.
The JHK photometric observations of all silicate carbon stars withdeclinations >-10° are presented. Combined with someobservational results in the visible and IRAS regions, the two-colordiagrams and energy distributions of the silicate carbon stars observedare discussed. Furthermore, their evolutionary characteristics are alsodiscussed.
| 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.
| Near Infrared Observation of Carbon and S Stars with Silicate Feature
Not Available
| 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.
| Probable candidates for silicate carbon stars in the northern Hemisphere
Near-infrared photometric data are compiled for possible candidates forsilicate carbon stars in the northern hemisphere which were selected onthe basis of the IRAS photometric data. Based on the characteristics ofglobal infrared photometric spectra, eight carbon stars are proposed asprobable candidates for silicate carbon stars. Silicate emission wasrecently reported for two of these candidates. Spectral observations inthe 10-micrometer wavelength region are needed for these candidates inorder to clarify whether or not they are true silicate carbon stars.
| New Spectra of Carbon Stars from the IRAS Low-Resolution Spectrometer
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1994MNRAS.268..113C&db_key=AST
| More H_2_O maser in J-type carbon stars
The detection of five new H_2_O masers in J-type carbon stars isreported, confirming the suggestion made earlier that they have anoxygen-rich environment. This increases the sample of peculiar carbonstars of this type to 13. The high maser detection rate suggests thatperhaps all J-type carbon stars with IRAS flux ratios S_25_/S_12_ >0.45 have oxygen-rich environment. Two of the new stars show largeradial velocities, stimulating the suggestion that these carbon starsbelong to the metal-weak halo population.
| New Candidates of Carbon Stars with Silicate Dust Features
Not Available
| Carbon stars with circumstellar silicate features
All stars in the General Catalogue of Cool Galactic Carbon Stars withIRAS 12 micrometer fluxes greater than 5 Jy were searched for lowresolution spectra (LRS) in the IRAS LRS database. Four more candidatesfor carbon stars with silicate features are found, bringing the total ofthis group of objects to 15. The spectral energy distributions of these15 stars are fitted with a detached shell model, and the results arefound to be consistent with the hypothesis that these stars representtransition objects between oxygen-rich and carbon-rich stars.
| Spectroscopic study of carbon stars with silicate features. 1: Observations
The results of an optical spectroscopic study of carbon stars withsilicate feature done at the Dominion Astrophysical Observatory (DAO) inVictoria in 1991 is presented. Four stars are confirmed to be C-13-richcarbon stars (J stars). Two stars are provisionally identified as Jstars. A preliminary spectral analysis is carried out. Two groups of Jstars were found in the IRAS color-color diagram. The 'red group'contains carbon stars with silicate emission feature which are good Jstar candidates; and the 'vertical strip group' contains standard Jstars which show weak or no SiC feature. It is suggested that thesources in the 'red group' represent the higher mass members of theasymptotic giant branch population. The enhancement of C-13 may beexplained by the envelope burning mechanism.
| Candidates for carbon stars with silicate features
Characteristics of color distributions in IRAS bands of carbon stars,which are well-known samples with silicate features, are examined. Somecandidates of carbon stars with silicate features are presented.
| 8-14 micron spectroscopy of carbon stars associated with silicate dust
Observations of 8-14-micron spectra of two known and two proposedsilicate carbon stars are reported. These data confirm the positionalassociation of BM Gem and V778 Cyg with the IRAS Low ResolutionSpectrometer silicate spectra. Moderate silicate emission was discoveredin the carbon star HD 189605. HD 100764 was not found to exhibitsignificant silicate emission.
| A general catalogue of cool carbon stars
Not Available
| Spectral classification of carbon stars by means of photoelectric photometry of line strengths.
Abstract image available at:http://adsabs.harvard.edu/abs/1977PASJ...29..731Y
| Kinematic properties of the carbon stars.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1976AJ.....81..364D&db_key=AST
| A general catalogue of cool carbon stars
Not Available
| Spectral Classifications for New of Previously Unlassified Carbon Stars.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1965ApJ...142..712S&db_key=AST
| Radial Velocities of 283 Stars of Spectral Classes R and N.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1944ApJ....99..145S&db_key=AST
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Наблюдательные данные и астрометрия
| Созвездие: | Орёл |
| Прямое восхождение: | 20h01m05.19s |
| Склонение: | -07°21'51.9" |
| Видимая звёздная величина: | 10.277 |
| Собственное движение RA: | 0 |
| Собственное движение Dec: | -9.2 |
| B-T magnitude: | 13.358 |
| V-T magnitude: | 10.532 |
Каталоги и обозначения:
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