Contents
Images
Upload your image
DSS Images Other Images
Related articles
New and Confirmed Triple Systems with Luminous Cool Primaries and Hot Companions
In the course of comparing parameters of evolved cool star plus hotmain-sequence star binaries with theoretical isochrones, somediscrepancies are found between implied stellar masses and thespectroscopic binary mass function or the measured angular separation.These are naturally explained if there is a third star in the system.Multiplicity is also required to explain some comparisons of ``cool plushot binary'' IUE and optical spectral energy distribution analysis withmeasured flux ratios, especially Tycho's two-color photometry ofseparate components. Out of a sample of 136 cool-plus-hot binary starsystems under study, measurements are now indicating several systemsconsidered double (HD 5373, 23089, 26673, 29094, 49126, 71129, 149379,179002, 187299), and probably a few others (including HD 136415), tohave at least three stellar components. Several other cases of suspectedtriple systems are confirmed. For comparison, there are eight knowntriples included in the project. In all, about 25% of the systemscontain three or more components within a few arcseconds. Estimatedseparations are provided, which may be of use when not known frominterferometry. In general, the triple systems have onepost-main-sequence component and two upper main-sequence components,usually revolving around each other. One new triple system, HD 149379,has as its middle component an F giant in the brief first crossing ofthe Hertzsprung gap.
| Spectroscopic binary orbits from photoelectric radial velocities. Paper 175: BD+48 1048, HR 1736, HR 3416, and HD 199378/9
Not Available
| Spectral Classification of the Hot Components of a Large Sample of Stars with Composite Spectra, and Implication for the Absolute Magnitudes of the Cool Supergiant Components.
A sample of 135 stars with composite spectra has been observed in thenear-UV spectral region with the Aurélie spectrograph at theObservatoire de Haute-Provence. Using the spectral classifications ofthe cool components previously determined with near infrared spectra, weobtained reliable spectral types of the hot components of the samplesystems. The hot components were isolated by the subtraction methodusing MK standards as surrogates of the cool components. We also derivedthe visual magnitude differences between the components usingWillstrop's normalized stellar flux ratios. We propose a photometricmodel for each of these systems on the basis of our spectroscopic dataand the Hipparcos data. We bring to light a discrepancy for the Gsupergiant primaries between the visual absolute magnitudes deduced fromHipparcos parallaxes and those tabulated by Schmidt-Kaler for the GIbstars: we propose a scale of Mv-values for these stars incomposite systems. By way of statistics, about 75% of the hot componentsare dwarf or subgiant stars, and 25% should be giants. The distributionin spectral types is as follows: 41% of B-type components, 57% of typeA, and 2% of type F; 68% of the hot components have a spectral type inthe range B7 to A2. The distribution of the ΔMv-valuesshows a maximum near 0.75 mag.
| Spectral classifications in the near infrared of stars with composite spectra. III. Study of a sample of 137 objects with the Aurelie spectrograph
We provide spectral classifications for a sample of 137 stars mentionedas having composite spectra. The classifications were carried out on 33Angstroms /mm spectra in the region 8370 - 8870 Angstroms. Of these 137objects, 115 correspond in the infrared to cool stars (G, K or M) ofluminosity classes III, II and I; for 22 stars, we find only hot spectraof types B, A, F or Am, so that they do not fulfil our definition ofcomposite spectra. We detect four new Am stars, and one Am star (HD70826) turns out to be a composite spectrum object. As in Paper II, thecool components of composite spectra show a strong concentration in thevicinity of G8III. Based upon observations carried out at Observatoirede Haute-Provence (OHP).
| Spectral classifications in the near infrared of stars with composite spectra. II. Study of a sample of 180 stars
A sample of 180 supposedly composite-spectrum stars has been studied onthe basis of spectra obtained in the near infrared (8370-8780 Angstroms)at a dispersion of 33 Anstroms/mm. The objective was to study the coolercomponents of the systems. Of our sample, 120 are true compositespectra, 35 are hot spectra of types B, F and 25 are Am stars. We find astrong concentration of the cooler components of the composite spectraaround G8III. In view of the difficulty of classifying compositespectra, because of the super position of an early type dwarf and a latetype giant or supergiant spectrum, we have made several tests to controlthe classification based upon the infrared region. Since all tests gavepositive results, we conclude that our classifications can be consideredas being both reliable and homogeneous. Table \ref{tab1} is alsoavailable electronically at the CDS via anonymous ftp 130.79.128.5 orhttp://cdsweb.u-strasbg.fr/Abstracts.html} Based upon observationscarried out at Observatoire de Haute-Provence (CNRS).
| 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.
| Composite spectra. V - Orbital elements for 30 systems
A comprehensive survey of bright composite-spectrum binaries in thenorthern sky has provided so many radial-velocity data that orbits cannow be determined for many objects whose orbits were hitherto unknown orelse insecure or actually erroneous. Elements are given for the orbitsof 30 such objects, thereby more than doubling the number ofcomposite-spectrum binaries with known orbits.
| Large and kinematically unbiased samples of G- and K-type stars. VI - Evolved stars in the Moore-Paddock-Wayman sample
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1990PASP..102..507E&db_key=AST
| Binary stars unresolved by speckle interferometry. III
The KPNO's 4-m telescope was used in 1975-1981 to determine the epochsof 1164 speckle observations for 469 unresolved, known or suspectedbinary stars. The data, presented in tabular form, encompass visualbinaries with eccentric orbits, occultation binaries, astrometricbinaries, Hyades stars of known or suspected duplicity, and many longperiod spectroscopic binaries.
| Meridian observations made with the Carlsberg Automatic Meridian Circle at Brorfelde (Copenhagen University Observatory) 1981-1982
The 7-inch transit circle instrument with which the present position andmagnitude catalog for 1577 stars with visual magnitudes greater than11.0 was obtained had been equipped with a photoelectric moving slitmicrometer and a minicomputer to control the entire observationalprocess. Positions are reduced relative to the FK4 system for each nightover the whole meridian rather than the usual narrow zones. Thepositions of the FK4 stars used in the least squares solution are alsogiven in the catalog.
| Radial Velocities, Spectral Types, and Luminosity Classes of 820 Stars.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1950ApJ...112...48M&db_key=AST
| A survey of stars with composite spectra.
Not Available
|
Submit a new article
Related links
Submit a new link
Member of following groups:
|
Observation and Astrometry data
| Constellation: | Delphinus |
| Right ascension: | 20h56m25.24s |
| Declination: | +14°48'58.6" |
| Apparent magnitude: | 7.32 |
| Distance: | 617.284 parsecs |
| Proper motion RA: | 3.9 |
| Proper motion Dec: | 0.9 |
| B-T magnitude: | 8.465 |
| V-T magnitude: | 7.415 |
Catalogs and designations:
|
