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Two-colour photometry for 9473 components of close Hipparcos double and multiple stars
Using observations obtained with the Tycho instrument of the ESAHipparcos satellite, a two-colour photometry is produced for componentsof more than 7 000 Hipparcos double and multiple stars with angularseparations 0.1 to 2.5 arcsec. We publish 9473 components of 5173systems with separations above 0.3 arcsec. The majority of them did nothave Tycho photometry in the Hipparcos catalogue. The magnitudes arederived in the Tycho B_T and V_T passbands, similar to the Johnsonpassbands. Photometrically resolved components of the binaries withstatistically significant trigonometric parallaxes can be put on an HRdiagram, the majority of them for the first time. Based on observationsmade with the ESA Hipparcos satellite.
| Catalogue of H-alpha emission stars in the Northern Milky Way
The ``Catalogue of Stars in the Northern Milky Way Having H-alpha inEmission" appears in Abhandlungen aus der Hamburger Sternwarte, Band XIin the year 1997. It contains 4174 stars, range {32degr <= l() II< 214degr , -10degr < b() II < +10degr } having the Hαline in emission. HBH stars and stars of further 99 lists taken from theliterature till the end of 1994 were included in the catalogue. We givethe cross-identification of stars from all lists used. The catalogue isalso available in the Centre de Données, Strasbourg ftp130.79.128.5 or http://cdsweb.u-strasbg.fr and at the HamburgObservatory via internet.
| The strongly constrained interacting binary BY Crucis.
We discuss spectroscopic and photometric observations (UV to IR) of BYCrucis, a new bright member of the interacting binaries of the WSerpentis class. The orbital period is 106.4days, and the mass functionamounts to 5.92Msun_. The primary is an early-F supergiantwhich fills its Roche lobe; the massive secondary is hidden inside athick accretion disk, which is probably the dominant light source in theultraviolet. The observed variations in the photometric lightcurves arecaused mainly by ellipsoidal variations. It is unlikely that an eclipseoccurs. A particularly interesting circumstance is that BY Cru is aprobable member of a visual multiple system which contains anotherevolved star. This circumstance enables us to estimate with someaccuracy the age of the interacting binary and the initial mass of theprimary. The history of this binary is then much more constrained thanfor the other W Serpentis stars. Also taking into account the fact thatthe binary has avoided Case C Roche lobe overflow, we determine upperand lower bounds for the initial and present masses of both components,and conclude that mass transfer has only been moderatelynon-conservative.
| Catalogue of stars in the northern Milky Way having H-alpha in emission
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.
| UBV Photometry of W Ser Stars
Not Available
| Radio continuum emission from stars: a catalogue update.
An updated version of my catalogue of radio stars is presented. Somestatistics and availability are discussed.
| A spectroscopic and photometric study of the giant star HD 101841: A very short-period binary system
The giant star HD 101841 is a single lined spectroscopic binary with anorbital period of 3.11 days and an assumed circular orbit. No sign ofhydrogen alpha emission or significant Li I 6707.81 A features werefound. Photometric observations show a micro-variability of about 0.014magnitude in V. Different studies give a F3II spectral classificationbut we found strong evidences that HD 101841 is probably a F3III-IVgiant star.
| UV Variability among F+B Interacting Binaries
Recent IUE observations at frequent epochs over a 10-week interval areused to explore the time variations in UV spectra and fluxes of 4 binarysystems: HD 37453 (F5 II + Be, 66.7d), HD 51956 (F8 Ib + B, 107.4d), HD59771 (F4 II + B, 89.9d), and PW Pup (F2ep Iab + B, 158d). In additionto having an evolved F primary and a hot secondary, these binaries sharethe properties of strong Hα emission (except 51956), irregularspectral variability, and UV signatures of mass transfer. Results on UVtime variations will be shown; the following preliminary conclusions arebased on partial completion of the observing program. Relatively smallvariations of 0.2-0.3 mag are seen for HD 37453 and HD 51956, while HD59771 shows large changes of 0.5 mag or more. These variations do notappear to correlate with orbital cycle. They may therefore be related tothe pulsationally-induced mass dumping phenomenon reported for theprototype for this group of binaries, HD 207739 (Parsons, Dempsey, &Bopp 1991, IAU Symp. 151, pg. 341). For this system, a saw-toothed UVflux cycle of 50.1d contrasts with the orbital period of 140.8d. SBP isa staff member of the Space Telescope Science Institute.
| HD 51956 - A supergiant in an interacting binary
IUE ultraviolet spectral observations reveal that the F supergiant HD51956 contains a hot companion star partially obscured by warm plasma.Variable absorption features are analogous to those in the stronglyinteracting system HD 207739. The F type component is apparentlytransferring matter to a subluminous B type star which originally wasthe primary component.
| 558 peculiar stars discovered at Abastumani
A list of 558 peculiar stars is given: 208 Ap stars, 342 Am stars, sevenobjects with composite spectra, and one Ba II star. All were discoveredat Abastumani Astrophysical Observatory in the course of classifyingstars in the galactic anticenter direction.
| IUE and stars with composite spectra
The IUE contribution to the study of binary stars is reviewed. The valueof ultraviolet spectra in defining the parameters of hot companions indouble systems is emphasized, as this is important for understanding ofthe masses, luminosities, and evolutionary states of both the componentstars. Cataclysmic variables; precataclysmics; symbiotic stars;atmospheric eclipsing binaries; Algols; cool and hot binaries; heavymetal stars; noninteractors; and Cepheids are discussed.
| HD 207739 and other F + Be variables
Characteristics for a group of composite spectrum stars which havestrong H alpha emission and peculiar satellite UV spectra are compared.Spectroscopic periods and photometric variability are discussed.Compared with normal noninteracting composite spectrum binaries, theyexhibit excess flux in the middle UV region. This is believed toindicate the presence of an accretion disk.
| Spectroscopy of unusual emission-line stars
New spectroscopic observations are reported for ten stars that have beenidentified in the literature as having H-alpha emission with suspectedF, G, or K spectral types. Three of the stars are shown to be BE stars,two are confirmed as early-type supergiants, three show composite (F orK + B) spectra, one is a 'post-T Tauri' star, and one is an ordinary Fstar without emission.
| The long-period K + Be binary HR 2577 (MWC 827)
New spectroscopic observations near H-alpha and Na I D, along withultraviolet IUE scans, have been obtained for the K + Be compositesystem HR 2577. High-precision radial-velocity measures do not supportthe suggested 58-year orbit of Hendry (1982). The H-alpha emission fromthe Be component undergoes considerable variations typical of its class.The presence of a Li I 6707 A feature as well as the IUE observationssupport the idea that little or no interaction between the binarycomponents of HR 2577 is taking place.
| A Polarimetric Prespective on the Close Binaries HD207739 and HD37453
Not Available
| Merged log of IUE observations.
Not Available
| U, V, W velocity components for the old disk using radial velocities of 1295 stars in the three cardinal Galactic directions
New radial velocities are presented for 1295 stars chosen at random nearthe three cardinal Galactic directions of l = 180 deg, b = 0; l = 90deg, b = 0 deg; and b = 90 deg, giving the distribution in U, V, and W,respectively, from the radial velocities alone. The measurements weremade with the coude spectrograph of the Mount Wilson 100 in. Hookerreflector. The purpose of the program is to set limits on the densitynormalization in the solar neighborhood of the old thin disk, the oldthick disk, and the halo. Many more high-velocity stars are present inthe unbiased sample than expected from previous estimates of thenormalization. The data suggest the density ratios in the solarneighborhood to be about 90 percent, 10 percent, and about 0.5 percentfor the thin disk, thick disk, and halo populations, respectively.
| Far-Ultraviolet Variability of HD 207739
Not Available
| Strange F + Be binary star systems
The IUE spectra of five stars with F or F + B optical spectra and strongBe star-like H alpha emission were obtained on several dates. No twoexposures of the strange optical variable HD 37453 are quite alike, MgII emission is strong, and the short wave prime (SWP) region has someresemblance to known interacting binaries such as SX Cas. The HD 43246shows significant Si IV absorption against an otherwise normal lateB-spectrum. The HD 166612 shows early B main-sequence spectral featuresexcept for evidence of a strong stellar wind. The HD 207739, discoveredin 1982 to show UV characteristics of a strongly interacting system,showed general brightening in the September observations, opposite tothe visual flux which decreased slightly. The far-UV spectrum of HD207739 was seen to evolve but to remain in between the two extremes seenin 1982, which differed greatly both in character and in absolute flux.
| Photometric variations of Orion population stars. III - RY Tau, T Ori, NV Ori, and HH AUR
UBVRI and H-alpha photometry of four Orion population stars has beenobtained with the Perkin telescope at Van Vleck Observatory during theinterval of October 1983 to March 1984. RY Tau underwent a dramaticincrease in brightness during this period, reaching a level (V = 9.43)not seen in more than two decades. At the same time, the equivalentwidth of its H-alpha emission line (measured photometrically) decreasedand, in the longer-wavelength color indices, has begun to show the'bluer when brighter' syndrome characteristic of other weakemission-line Orion population stars. Spectra taken during the 1983-1984season, or as soon as possible this season (if the star remains bright),could provide critical information on the nature of the variabilitymechanism. T Ori and NV Ori also showed substantial variability, andtheir color and H-alpha characteristics are discussed. HH Aur showedlittle or no variation during the present observations.
| Estimation of spectral classifications for bright northern stars with interesting Stromgren indices
The purpose of this investigation is to provide spectroscopic observerswith finding lists of potentially interesting objects. From anunpublished UVBY catalogue of 7026 northern stars (mostly brighter than8.3m) 1094 objects with interesting combinations of UVBY indices havebeen selected. Most stars with post-HD classifications have beenexcluded, as well as late F dwarfs belonging to the intermediatepopulation II. For the 792 remaining stars estimated spectralclassifications are given. The techniques and experience from a previouspaper dealing with southern stars have been utilized here. Among thepredicted spectral classifications are 40 OB stars; 262 Ap, Am, or Fmstars; 16 supergiants of types A to G; 110 bright giants of types A to K(class II); 156 double stars or objects with composite spectra; 26 lateF dwarfs; 91 weak-lined dwarf and giant stars of types F to K, includingearly F-type population II field blue stragglers; and a few possiblefield horizontal branch stars, lambda Bootis-type stars, and late-typehalo giants.
| Observations of radio stars at 10.6 GHz
Results are outlined for a program conducted over a period of about twoyears in order to detect and monitor stellar radio emission. A list ofsome 170 candidate radio stars is presented which includes spectraltypes, apparent magnitudes, and distances (where known). Flux densitiesare provided for each of the following stars that were detected at leastonce at a frequency of 10.6 GHz: R Aql, Cyg X-1, Cyg X-3, AR Lac, BetaLyr, Algol, RY Sct, and MWC 349. It is noted that a flare was observedon R Aql, Cyg X-1 exhibited considerable radio variability, Cyg X-3experienced intense radio flaring on several occasions, and the radiospectra of both RY Sct and MWC 349 appear to have a thermal origin. Apossible division of the known radio stars into two classes on the basisof variability time scale is considered.
| New double stars (12th series) discovered at Nice
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1975A&AS...20..379C&db_key=AST
| 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
| Discovery and Observations of Stars of Class Be. Third Paper.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1942ApJ....96...15M&db_key=AST
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| Takýmyýldýz: | Arabaci |
| Sað Açýklýk: | 05h39m56.62s |
| Yükselim: | +30°05'11.2" |
| Görünürdeki Parlaklýk: | 8.162 |
| Uzaklýk: | 438.596 parsek |
| özdevim Sað Açýklýk: | -2.2 |
| özdevim Yükselim: | -3.6 |
| B-T magnitude: | 9.072 |
| V-T magnitude: | 8.238 |
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