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The Infrared Telescope Facility (IRTF) Spectral Library: Cool Stars
We present a 0.8-5 μm spectral library of 210 cool stars observed ata resolving power of R ≡ λ/Δλ ~ 2000 with themedium-resolution infrared spectrograph, SpeX, at the 3.0 m NASAInfrared Telescope Facility (IRTF) on Mauna Kea, Hawaii. The stars havewell-established MK spectral classifications and are mostly restrictedto near-solar metallicities. The sample not only contains the F, G, K,and M spectral types with luminosity classes between I and V, but alsoincludes some AGB, carbon, and S stars. In contrast to some otherspectral libraries, the continuum shape of the spectra is measured andpreserved in the data reduction process. The spectra are absolutely fluxcalibrated using the Two Micron All Sky Survey photometry. Potentialuses of the library include studying the physics of cool stars,classifying and studying embedded young clusters and optically obscuredregions of the Galaxy, evolutionary population synthesis to studyunresolved stellar populations in optically obscured regions of galaxiesand synthetic photometry. The library is available in digital form fromthe IRTF Web site.
| Spectroscopic binaries among Hipparcos M giants. III. The eccentricity - period diagram and mass-transfer signatures
Context: This paper is the third one in a series devoted to studying theproperties of binaries involving M giants. Aims: We use a new set oforbits to construct the first (e - log P) diagram of an extensive sampleof M giant binaries, to obtain their mass-function distribution, and toderive evolutionary constraints for this class of binaries and relatedsystems. Methods: The orbital properties of binaries involving M giantswere analysed and compared with those of related families of binaries (Kgiants, post-AGB stars, barium stars, Tc-poor S stars). Results: Theorbital elements of post-AGB stars and M giants are not very different,which may indicate that, for the considered sample of post-AGB binaries,the post-AGB star left the AGB at quite an early stage (M4 or so).Neither are the orbital elements of post-mass-transfer binaries likebarium stars very different from those of M giants, suggesting that themass transfer did not alter the orbital elements much, contrary tocurrent belief. Finally, we show that binary systems with e < 0.4 logP - 1 (with periods expressed in days) are predominantlypost-mass-transfer systems, because (i) the vast majority of barium andS systems match this condition; and (ii) these systems have companionmasses peaking around 0.6 Mȯ, as expected for whitedwarfs. The latter property has been shown to hold as well foropen-cluster binaries involving K giants, for which a lower bound on thecompanion mass may easily be set.Based on observations carried out at the Swiss telescope installed atthe Observatoire de Haute Provence (OHP, France), and at the 1.93-m OHPtelescope.
| Element Enhancements along the Entire Asymptotic Giant Branch Phase
The results of a study of the asymptotic giant branch (AGB) phase ofstellar evolution are presented. Abundances have been determined for Fe,C, O, the light s-process elements, Y and Zr, the heavy s-processelements, La and Nd, and the r-process element, Eu. The expectedrelationship between enhanced C, increasing C/O ratio, and enhanceds-process elements has been quantified. Results are presented to provideobservational data with which to compare theoretical predictions. Theresults in this paper confirm previously suggested relationships betweenC, C/O, and s-process element enhancements. It is seen that AGB starsshow C/O ratios from C/O ~ 0.4 to 1.0, while C enhancements lie between[C/Fe] = 0.1-0.9 dex. Enhancements of s-process elements are as much as[s/Fe] ~ 1.0 dex for the stars in which C is also greatly enhanced.
| A new stellar library in the region of the CO index at 2.3 μm. New index definition and empirical fitting functions
Context: The analysis of unresolved stellar populations demandsevolutionary synthesis models with realistic physical ingredients andextended wavelength coverage. Aims: We quantitatively describe thefirst CO bandhead at 2.3 μm to allow stellar population models toprovide improved predictions in this wavelength range. Methods: Weobserved a new stellar library with a better coverage of the stellaratmospheric parameter space than in earlier works. We performed adetailed analysis of the robustness of previous CO index definitionswith spectral resolution, wavelength calibration, signal-to-noise ratio,and flux calibration. Results: We define a new line-strength index forthe first CO bandhead at 2.3 μm, D_CO, better suited for stellarpopulation studies than previous index definitions. We derive empiricalfitting functions for the CO feature as a function of the stellarparameters (T_eff, log g and [Fe/H]), showing a detailed quantitativemetallicity dependence.
| AGB stars of the intermediate-age LMC cluster NGC 1846. II. Dredge up along the AGB
Aims: We investigate the change in the surface abundance of12C during the evolution along the AGB, aiming to constrainthird dredge-up models. Methods: High-resolution, near-infraredspectra of a sample of AGB stars in the LMC cluster NGC 1846 wereobtained. A cluster sample ensures a high level of homogeneity withrespect to age, metallicity, and distance. The C/O ratio and the ratioof 12C/13C were measured and compared with ourevolutionary models. Results: For the first time, we show theevolution of the C/O and 12C/13C ratios along acluster AGB. Our findings allow us to check the reliability of theevolutionary models and, in particular, the efficiency of the thirddredge up. The increase in both C/O and 12C/13C inthe observed O-rich stars is reproduced by the models well. However, thelow carbon isotopic ratios of the two C-stars in our sample indicate thelate occurrence of moderate extra mixing. The extra mixing affects themost luminous AGB stars and is capable of increasing the abundance of13C, while leaving unchanged the C/O ratio, which has beenfixed by the cumulative action of several third dredge-up episodes. Wefind indications that the F abundance also increases along the AGB,supporting an in situ production of this element.
| Medium-resolution Isaac Newton Telescope library of empirical spectra - II. The stellar atmospheric parameters
We present a homogeneous set of stellar atmospheric parameters(Teff, logg, [Fe/H]) for MILES, a new spectral stellarlibrary covering the range λλ 3525-7500Å at2.3Å (FWHM) spectral resolution. The library consists of 985 starsspanning a large range in atmospheric parameters, from super-metal-rich,cool stars to hot, metal-poor stars. The spectral resolution, spectraltype coverage and number of stars represent a substantial improvementover previous libraries used in population synthesis models. Theatmospheric parameters that we present here are the result of aprevious, extensive compilation from the literature. In order toconstruct a homogeneous data set of atmospheric parameters we have takenthe sample of stars of Soubiran, Katz & Cayrel, which has very welldetermined fundamental parameters, as the standard reference system forour field stars, and have calibrated and bootstrapped the data fromother papers against it. The atmospheric parameters for our clusterstars have also been revised and updated according to recent metallicityscales, colour-temperature relations and improved set of isochrones.
| Pulkovo compilation of radial velocities for 35495 stars in a common system.
Not Available
| Two Micron All Sky Survey, Infrared Astronomical Satellite, and Midcourse Space Experiment Color Properties of Intrinsic and Extrinsic S Stars
We attempt to select new candidate intrinsic and extrinsic S stars inthe General Catalogue of Galactic S Stars (GCGSS) by combining data fromthe Two Micron All Sky Survey, the Infrared Astronomical Satellite, andthe Midcourse Space Experiment. Catalog entries are cross-identified,yielding 528 objects, out of which 29 are known extrinsic S stars and 31are known intrinsic S stars. Their color-color diagrams,(H-[12])-(K-[12]) and (K-[12])-(J-[25]), are drawn and used to identifya new sample of 147 extrinsic and 256 intrinsic S star candidates, whilethe nature of 65 stars remains identified. We infer that about 38%+/-10%of the GCGSS objects are of extrinsic type. Moreover, we think thatcolors such as J-[25] can be used to split off the two categories of Sstars, while single colors are not appropriate. The color-colordiagrams, such as (H-[12])-(K-[12]) and (K-[12])-(J-[25]), are proven tobe powerful tools for distinguishing the two kinds of S stars.
| Medium-resolution Isaac Newton Telescope library of empirical spectra
A new stellar library developed for stellar population synthesismodelling is presented. The library consists of 985 stars spanning alarge range in atmospheric parameters. The spectra were obtained at the2.5-m Isaac Newton Telescope and cover the range λλ3525-7500 Å at 2.3 Å (full width at half-maximum) spectralresolution. The spectral resolution, spectral-type coverage,flux-calibration accuracy and number of stars represent a substantialimprovement over previous libraries used in population-synthesis models.
| How many Hipparcos Variability-Induced Movers are genuine binaries?
Hipparcos observations of some variable stars, and especially oflong-period (e.g. Mira) variables, reveal a motion of the photocentercorrelated with the brightness variation (variability-induced mover -VIM), suggesting the presence of a binary companion. A re-analysis ofthe Hipparcos photometric and astrometric data does not confirm the VIMsolution for 62 among the 288 VIM objects (21%) in the Hipparcoscatalogue. Most of these 288 VIMs are long-period (e.g. Mira) variables(LPV). The effect of a revised chromaticity correction, which accountsfor the color variations along the light cycle, was then investigated.It is based on ``instantaneous'' V-I color indices derived fromHipparcos and Tycho-2 epoch photometry. Among the 188 LPVs flagged asVIM in the Hipparcos catalogue, 89 (47%) are not confirmed as VIM afterthis improved chromaticity correction is applied. This dramatic decreasein the number of VIM solutions is not surprising, since the chromaticitycorrection applied by the Hipparcos reduction consortia was based on afixed V-I color. Astrophysical considerations lead us to adopt a morestringent criterion for accepting a VIM solution (first-kind risk of0.27% instead of 10% as in the Hipparcos catalogue). With this moresevere criterion, only 27 LPV stars remain VIM, thus rejecting 161 ofthe 188 (86%) of the LPVs defined as VIMs in the Hipparcos catalogue.Based on observations from the Hipparcos astrometric satellite operatedby the European Space Agency (ESA 1997).Table 1 is also available in electronic form at the CDS, via anonymousftp to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/399/1167
| 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
| Near-infrared observations of candidate extrinsic S stars
Photometric observations in the near infrared for 161 S stars, including18 Tc-rich (intrinsic) stars, 19 Tc-deficient (extrinsic) ones and 124candidates for Tc-deficient S stars, are presented in this paper. Basedon some further investigations into the infrared properties of bothTc-rich and Tc-deficient S stars, 104 candidates are identified as verylikely Tc-deficient S stars. The large number of infrared-selectedTc-deficient S stars provides a convenient way to study the physicalproperties and the evolutionary status of this species of S stars.
| Stellar and circumstellar evolution of long period variable stars
In a first paper, HIPPARCOS astrometric and kinematic data were used tocalibrate both infrared K and IRAS luminosities at the same time askinematic parameters of Long Period Variable stars (LPVs). Individualestimated absolute magnitudes and a probabilistic assignation togalactic populations were deduced from these calibrations for each LPVof our sample. Here we propose a scenario of simultaneous stellar andcircumstellar evolution according to the galactic populations. Thetransitory states of S and Tc stars allow us to confirm the location ofthe first dredge-up at Mbol=-3.5. There is also evidencesuggesting that a previous enrichment in s-elements from a more evolvedcompanion may accelerate the evolution along the AGB. The possibleevolution to OH LPVs is included in this scenario, and any of thesestars may have a mass at the limit of the capability for a C enrichmentup to C/O > 1. A list of bright massive LPVs with peculiar envelopeand luminosity properties is proposed as Hot Bottom Burning candidates.The He-shell flash star, R Cen, is found to be exceptionally bright andcould become, before leaving the AGB, a C-rich LPV brighter than theusual luminosity limit of carbon stars.
| Lower limits on the maximum orbital frequency around rotating strange stars
Observations of kHz quasi-periodic oscillations (QPOs) in the X-rayfluxes of low-mass X-ray binaries (LMXBs) have been used in attempts toconstrain the external metric of the compact members of these binaries,as well as their masses and the equations of state of matter atsupranuclear denisties. We compute the maximum orbital frequency ofstable circular motion around uniformly rotating strange stars describedby the MIT bag model. The calculations are performed for both normal andsupramassive constant baryon mass sequences of strange stars rotating atall possible rates. We find the lower limits on the maximum orbitalfrequency and discuss them for a range of masses and for all rotationalfrequencies allowed in the model considered. We show that for slowly andmoderately rotating strange stars the maximum value of orbital frequencycan be a good indicator of the mass of the compact object. However, forrapidly rotating strange stars the same value of orbital frequency inthe innermost stable circular orbit is obtained for stars with massesranging from that of a planetoid to about three solar masses. Atsufficiently high rotation rates of the strange star, the rotationalperiod alone constrains the stellar mass to a surprisingly narrow range.
| Nucleosynthesis and Mixing on the Asymptotic Giant Branch. III. Predicted and Observed s-Process Abundances
We present the results of s-process nucleosynthesis calculations forasymptotic giant branch (AGB) stars of different metallicities anddifferent initial stellar masses (1.5 and 3 Msolar), and wepresent comparisons of them with observational constraints fromhigh-resolution spectroscopy of evolved stars over a wide metallicityrange. The computations were based on previously published stellarevolutionary models that account for the third dredge-up phenomenonoccurring late on the AGB. Neutron production is driven by the13C(α,n)16O reaction during the interpulseperiods in a tiny layer in radiative equilibrium at the top of the He-and C-rich shell. The neutron source 13C is manufacturedlocally by proton captures on the abundant 12C; a few protonsare assumed to penetrate from the convective envelope into the radiativelayer at any third dredge-up episode, when a chemical discontinuity isestablished between the convective envelope and the He- and C-richzones. A weaker neutron release is also guaranteed by the marginalactivation of the reaction 22Ne(α,n)25Mgduring the convective thermal pulses. Owing to the lack of a consistentmodel for 13C formation, the abundance of 13Cburnt per cycle is allowed to vary as a free parameter over a wideinterval (a factor of 50). The s-enriched material is subsequently mixedwith the envelope by the third dredge-up, and the envelope compositionis computed after each thermal pulse. We follow the changes in thephotospheric abundance of the Ba-peak elements (heavy s [hs]) and thatof the Zr-peak ones (light s [ls]), whose logarithmic ratio [hs/ls] hasoften been adopted as an indicator of the s-process efficiency (e.g., ofthe neutron exposure). Our model predictions for this parameter show acomplex trend versus metallicity. Especially noteworthy is theprediction that the flow along the s-path at low metallicities drainsthe Zr and Ba peaks and builds an excess at the doubly magic208Pb, which is at the termination of the s-path. We thendiscuss the effects on the models of variations in the crucialparameters of the 13C pocket, finding that they are notcritical for interpreting the results. The theoretical predictions arecompared with published abundances of s-elements for AGB giants ofclasses MS, S, SC, post-AGB supergiants, and for various classes ofbinary stars, which supposedly derive their composition by mass transferfrom an AGB companion. This is done for objects belonging both to theGalactic disk and to the halo. The observations in general confirm thecomplex dependence of neutron captures on metallicity. They suggest thata moderate spread exists in the abundance of 13C that isburnt in different stars. Although additional observations are needed,it seems that a good understanding has been achieved of s-processoperation in AGB stars. Finally, the detailed abundance distributionincluding the light elements (CNO) of a few s-enriched stars atdifferent metallicities are examined and satisfactorily reproduced bymodel envelope compositions.
| 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).
| Catalogue of [Fe/H] determinations for FGK stars: 2001 edition
The catalogue presented here is a compilation of published atmosphericparameters (Teff, log g, [Fe/H]) obtained from highresolution, high signal-to-noise spectroscopic observations. This newedition has changed compared to the five previous versions. It is nowrestricted to intermediate and low mass stars (F, G and K stars). Itcontains 6354 determinations of (Teff, log g, [Fe/H]) for3356 stars, including 909 stars in 79 stellar systems. The literature iscomplete between January 1980 and December 2000 and includes 378references. The catalogue is made up of two tables, one for field starsand one for stars in galactic associations, open and globular clustersand external galaxies. The catalogue is distributed through the CDSdatabase. Access to the catalogue with cross-identification to othersets of data is also possible with VizieR (Ochsenbein et al.\cite{och00}). The catalogue (Tables 1 and 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/373/159 and VizieRhttp://vizier.u-strasbg.fr/.
| A search for Technetium in semiregular variables
We searched for the lines of Tc in the spectra of Semiregular variables(SRVs) in the wavelength region from 4180 to 4300 Å using highresolution spectroscopy. Tc as an s-process element is produced on thethermally pulsing AGB and is therefore a good indicator for theevolutionary status of Semiregular variables. Combining our results withprevious investigations we get a database large enough for a statisticalstudy. Tc is not found in SRVs with periods below 100 days, spectraltypes earlier than M5 and photospheric IRAS colours. These objects are`blue' SRVs in the classification system of Kerschbaum & Hron(\cite{KH94}). Among the `red' SRVs (periods longer than 100 days) thefraction of stars showing Tc in their spectra is about 15 % with aprobably lower fraction among the stars with periods above 150 days.This is significantly lower than for the typical Miras. Taking intoaccount the probable conditions for the occurence of the third dredge-upand the expected behavior of the Tc abundance along an evolutionarytrack on the AGB, our results support an evolutionary scenario from`blue' SRVs (early AGB) to `red' SRVs (early TP-AGB) and on to longperiod Miras. Only the most massive (masses above 2M_ȯ) stars showTc during the SRV stage. The luminosities of the Tc-rich SRVs and Mirasare compatible with theoretical estimates of the minimum core massrequired for the third dredge-up. Based on observations collected at theEuropean Southern Observatory, La Silla, Chile (ESO No.54.E-0350), theGerman Spanish Astronomical Centre, Calar Alto, operated by theMax-Planck-Institute for Astronomy, Heidelberg, jointly with the SpanishNational Commission for Astronomy, and Kitt Peak National Observatory,USA.
| Infrared study of the two categories of S stars
Photometric observations of 20 Tc-deficient and 24 Tc-rich S stars inthe near infrared are presented in this paper. With the IRAS data,infrared two color diagrams, IRAS low-resolution spectra and energydistributions are discussed to summarize the way to segregate Tc-richstars from Tc-deficient ones.
| On the Variability of S Stars as Observed by the Hipparcos
The Hipparcos photometry of S type stars shows that they are allvariable. The intrinsic S stars show a larger range of amplitudes thando the extrinsic S stars.
| The HIPPARCOS Hertzsprung-Russell diagram of S stars: probing nucleosynthesis and dredge-up
HIPPARCOS trigonometrical parallaxes make it possible to compare thelocation of Tc-rich and Tc-poor S stars in the Hertzsprung-Russell (HR)diagram: Tc-rich S stars are found to be cooler and intrinsicallybrighter than Tc-poor S stars. The comparison with the Genevaevolutionary tracks reveals that the line marking the onset of thermalpulses on the asymptotic giant branch (AGB) matches well the observedlimit between Tc-poor and Tc-rich S stars. Tc-rich S stars are, asexpected, identified with thermally-pulsing AGB stars of low andintermediate masses, whereas Tc-poor S stars comprise mostly low-massstars (with the exception of 57 Peg) located either on the red giantbranch or on the early AGB. Like barium stars, Tc-poor S stars are knownto belong exclusively to binary systems, and their location in the HRdiagram is consistent with the average mass of 1.6+/-0.2 Msb ȯderived from their orbital mass-function distribution (Jorissen et al.1997, A&A, submitted). A comparison with the S stars identified inthe Magellanic Clouds and in the Fornax dwarf elliptical galaxy revealsthat they have luminosities similar to the galactic Tc-rich S stars.However, most of the surveys of S stars in the external systems did notreach the lower luminosities at which galactic Tc-poor S stars arefound. The deep Westerlund survey of carbon stars in the SMC uncovered afamily of faint carbon stars that may be the analogues of thelow-luminosity, galactic Tc-poor S stars. Based on data from theHIPPARCOS astrometry satellite
| Proper motions, absolute magnitudes and spatial distribution of zirconium stars.
Not Available
| 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.
| A catalogue of [Fe/H] determinations: 1996 edition
A fifth Edition of the Catalogue of [Fe/H] determinations is presentedherewith. It contains 5946 determinations for 3247 stars, including 751stars in 84 associations, clusters or galaxies. The literature iscomplete up to December 1995. The 700 bibliographical referencescorrespond to [Fe/H] determinations obtained from high resolutionspectroscopic observations and detailed analyses, most of them carriedout with the help of model-atmospheres. The Catalogue is made up ofthree formatted files: File 1: field stars, File 2: stars in galacticassociations and clusters, and stars in SMC, LMC, M33, File 3: numberedlist of bibliographical references The three files are only available inelectronic form at the Centre de Donnees Stellaires in Strasbourg, viaanonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5), or viahttp://cdsweb.u-strasbg.fr/Abstract.html
| The nucleosynthesis of heavy elements in low-mass AGB stars
We take 13C(α,n)16O as neutron source, allowfor variation of the mass of the nucleus with thermal pulse number andadopt the unbranched s process path from 56Fe to210Bi in an attempt to explain the overabundance of heavyelements in MS and S stars. We found stars with larger masses havelarger dilution factors because of a stronger convection and that thesestars fall in four different regions in the abundance diagram, thusenabling a rough estimate of the mass to be made. We show that, for a2.5 Msolar star, the third dredge-up stops after a certain number ofpulses because of the formation of a hollow shell structure, so the starwill show no Tc and this can account for the existence of binary systemsconsisting of a ``Tc-no'' AGB star with a main-sequence star companion.
| The heavy elements nucleosynthesis in the low mass AGB stars.
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.
| A catalogue of associations between IRAS sources and S stars.
Cross identifications between the General Catalogue of Galactic S Stars(GCGSS), the IRAS Point Source Catalogue (PSC), and the Guide StarCatalogue (GSC) are presented. The purpose of the present catalogue isi) to provide a clean sample of S stars with far-IR data, and ii) toprovide accurate GSC positions for S stars, superseding those listed inthe GCGSS. The IRAS colour-colour diagram and the galactic distributionof S stars associated with an IRAS source are presented. Several S starshaving extended images in at least one IRAS band have also beenidentified.
| The Chemical Composition of Red Giants. IV. The Neutron Density at the s-Process Site
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1995ApJ...450..302L&db_key=AST
| Circumstellar Properties of S Stars. I. Dust Features
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1993ApJ...416..769C&db_key=AST
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Datos observacionales y astrométricos
| Constelación: | Popa |
| Ascensión Recta: | 07h53m05.27s |
| Declinación: | -11°37'29.3" |
| Magnitud Aparente: | 7.614 |
| Distancia: | 332.226 parsecs |
| Movimiento Propio en Ascensión Recta: | -5.3 |
| Movimiento Propio en Declinación: | -6 |
| B-T magnitude: | 9.839 |
| V-T magnitude: | 7.798 |
Catálogos y designaciones:
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