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.
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Proper motions, absolute magnitudes and spatial distribution of zirconium stars.
Not Available
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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.
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The Henry Draper Extension Charts: A catalogue of accurate positions, proper motions, magnitudes and spectral types of 86933 stars
The Henry Draper Extension Charts (HDEC), published in the form offinding charts, provide spectral classification for some 87000 starsmostly between 10th and 11th magnitude. This data, being highlyvaluable, as yet was practically unusable for modern computer-basedastronomy. An earlier pilot project (Roeser et al. 1991) demonstrated apossibility to convert this into a star catalogue, using measurements ofcartesian coordinates of stars on the charts and positions of theAstrographic Catalogue (AC) for subsequent identification. We presenthere a final HDEC catalogue comprising accurate positions, propermotions, magnitudes and spectral classes for 86933 stars of the HenryDraper Extension Charts.
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Infrared properties and evolution of MSC stars
IRAS photometric data are used to investigate low-resolution spectra,near-IR photometric data, visible spectral features, and main abundanceratios of MSC stars and the physicochemical processes taking place intheir interior. Their possible evolutionary states are discussed, and itis argued that both the sequence M - S - C and the direct sequence M - Care possible.
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Infrared Spectra and Circumstellar Emission of Late-Type Stars. III. S-Type Stars
Near-infrared photometry was carried out at the J, H, K, and L bands for73 S-type stars. The statistical characteristics of the infrared spectraand the circumstellar emission of S-type stars were examined usingnear-infrared photometric data, IRAS photometric data, and thelow-resolution spectra obtained by IRAS. The characteristics of thephotometric spectra of S-type stars were compared with those ofoxygen-rich stars and carbon stars. We found that MS and SC stars haveinfrared spectral characteristics similar to those of both oxygen-richstars and carbon stars, respectively. However, mild S, medium S, andstrong S stars were found to have a variety of spectral characteristicsin the infrared region. Correlations between the 10-mu m spectralfeatures and infrared photometric spectra were examined. It was foundthat S-type stars show a variety of spectral characteristics regardingboth the 10-mu m spectral feature and photometric spectra.
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Mass loss from S stars
The mass-loss process in S stars is studied using 65 S stars from thelisting of Wing and Yorka (1977). The role of pulsations in themass-loss process is examined. It is detected that stars with largermass-loss rates have a greater amplitude of pulsations. The dust-to-gasratio for the S stars is estimated as 0.002 and the average mass-lossrate is about 6 x 10 to the -8th solar masses/yr. Some of the propertiesof the S stars, such as scale height, surface density, and lifetime, aremeasured. It is determined that scale height is 200 pc; the totalduration of the S star phase is greater than or equal to 30,000 yr; andthe stars inject 3 x 10 to the -6th solar masses/sq kpc yr into theinterstellar medium.
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JHK Photometry of S-Type Stars
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Near infrared photometry of S-type stars
JHK photometry of some S-type stars is presented in this paper. Combinedwith normal M giants and carbon stars, some properties of S-type starsare shown in the two-color diagram. Relationship between periods andcolors in the near infrared are also described.
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A General Catalogue of Galactic S-Stars - ED.2
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A Search for S-Stars in the IRC and AFGL Catalogues
Seventeen unidentified sources contained in the 2jt JR Catalogue, andAFGL-AFGLS Catalogues have been tentatively indicated as S stars from acomparison with the General Catalogue of S stars. An analysis based onthe I - K and K - [4.2j.~] behavior has been performed for all thesources which have been found to be in common with all the abovementioned catalogues. The results lead to the conclusion that thepresence of circumstellar shells seems to be very unlike for theseobjects in spite of their evolutionary status which is intermediatebetween M and C type stars
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Spectral types of S and SC stars on the revised MK system
The catalog of 101 stars provides standards of spectral type in thesequence from MS through S and SC to the carbon stars with weak C2bands. In addition to temperature types and C/O indices, intensities ofZrO, TiO, Na D lines, YO, and Li 6708 are given whenever possible. Forvariables of large amplitude the observations at different dates aretabulated.
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The brightest S-type stars in the infrared
Lists of the brightest stars of type S at infrared wavelengths, based onsearches in the IRC and AFCRL catalogs, are presented in the hope ofstimulating further spectroscopic observations of S stars in theinfrared; the importance of such observations is stressed. Anexamination of the K magnitudes of the brightest stars having variousdegrees of S characteristics shows that the marginal MS stars are morecommon than stars with strong S characteristics, although they are alsomore difficult to recognize. It is found that the number ratio of coolcarbon stars to S stars, when selected in the same way according toinfrared magnitude and region of the sky, is about 3:1.
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A general catalogue of S stars.
Not Available
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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
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Classification of the S-Type Stars.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1954ApJ...120..484K&db_key=AST
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