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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.
| 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.
| A CORAVEL radial-velocity monitoring of giant BA and S stars: Spectroscopic orbits and intrinsic variations. I.
With the aim of deriving the binary frequency among Ba and S stars, 56new spectroscopic orbits (46 and 10, respectively) have been derived forthese chemically-peculiar red giants monitored with the \coravel\spectrometers. These orbits are presented in this paper (38 orbits) andin a companion paper \cite[(Udry et al. 1998,]{Udry} Paper II; 18orbits). The results for 12 additional long-period binary stars (6 and6, respectively), for which only minimum periods (generally exceeding 10y) can be derived, are also presented here (10) and in Paper II (2). Theglobal analysis of this material, with a few supplementary orbits fromthe literature, is presented in \cite[Jorissen et al.(1998).]{Jorissen98} For the subsample of Mira S, SC and (Tc-poor) Cstars showing intrinsic radial-velocity variations due to atmosphericphenomena, orbital solutions (when available) have been retained if thevelocity and photometric periods are different (3 stars). However, it isemphasized that these orbit determinations are still tentative. Threestars have been found with radial-velocity variations synchronous withthe light variations. Pseudo-orbital solutions have been derived forthose stars. In the case of RZ Peg, a line-doubling phenomenon isobserved near maximum light, and probably reflects the shock wavepropagating through the photosphere. Based on observations obtained atthe Haute-Provence Observatory (France) and at the European SouthernObservatory (ESO, La Silla, Chile).
| Insights into the formation of barium and Tc-poor S stars from an extended sample of orbital elements
The set of orbital elements available for chemically-peculiar red giant(PRG) stars has been considerably enlarged thanks to a decade-longCORAVEL radial-velocity monitoring of about 70 barium stars and 50 Sstars. When account is made for the detection biases, the observedbinary frequency among strong barium stars, mild barium stars andTc-poor S stars (respectively 35/37, 34/40 and 24/28) is compatible withthe hypothesis that they are all members of binary systems. Thesimilarity between the orbital-period, eccentricity and mass-functiondistributions of Tc-poor S stars and barium stars confirms that Tc-poorS stars are the cooler analogs of barium stars. A comparative analysisof the orbital elements of the various families of PRG stars, and of asample of chemically-normal, binary giants in open clusters, revealsseveral interesting features. The eccentricity - period diagram of PRGstars clearly bears the signature of dissipative processes associatedwith mass transfer, since the maximum eccentricity observed at a givenorbital period is much smaller than in the comparison sample of normalgiants. be held The mass function distribution is compatible with theunseen companion being a white dwarf (WD). This lends support to thescenario of formation of the PRG star by accretion of heavy-element-richmatter transferred from the former asymptotic giant branch progenitor ofthe current WD. Assuming that the WD companion has a mass in the range0.60+/-0.04 Msb ȯ, the masses of mild and strong barium starsamount to 1.9+/-0.2 and 1.5+/-0.2 Msb ȯ, respectively. Mild bariumstars are not restricted to long-period systems, contrarily to what isexpected if the smaller accretion efficiency in wider systems were thedominant factor controlling the pollution level of the PRG star. Theseresults suggest that the difference between mild and strong barium starsis mainly one of galactic population rather than of orbital separation,in agreement with their respective kinematical properties. There areindications that metallicity may be the parameter blurring the period -Ba-anomaly correlation: at a given orbital period, increasing levels ofheavy-element overabundances are found in mild barium stars, strongbarium stars, and Pop.II CH stars, corresponding to a sequence ofincreasingly older, i.e., more metal-deficient, populations. PRG starsthus seem to be produced more efficiently in low-metallicitypopulations. Conversely, normal giants in barium-like binary systems mayexist in more metal-rich populations. HD 160538 (DR Dra) may be such anexample, and its very existence indicates at least that binarity is nota sufficient condition to produce a PRG star. This paper is dedicated tothe memory of Antoine Duquennoy, who contributed many among theobservations used in this study
| 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 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.
| S stars: infrared colors, technetium, and binarity
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1993A&A...271..463J&db_key=AST
| 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.
| JHK Photometry of S-Type Stars
Not Available
| 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.
| A General Catalogue of Galactic S-Stars - ED.2
Not Available
| Discoveries on Southern Red-Sensitive Objective-Prism Plates - Part Two - New Ms-Stars Carbon-Stars and Sc-Stars
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1979A&AS...38..335M&db_key=AST
| The Distribution of the BD M-Type Stars Along the Galactic Equator.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1958ApJ...128..510N&db_key=AST
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Observation and Astrometry data
| Constellation: | Monoceros |
| Right ascension: | 06h36m12.12s |
| Declination: | +01°57'29.2" |
| Apparent magnitude: | 9.41 |
| Proper motion RA: | -0.7 |
| Proper motion Dec: | -0.1 |
| B-T magnitude: | 11.65 |
| V-T magnitude: | 9.595 |
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