Садржај
Слике
Уплоадјуј своје слике
DSS Images Other Images
Везани чланци
VSOP: the variable star one-shot project. I. Project presentation and first data release
Context: About 500 new variable stars enter the General Catalogue ofVariable Stars (GCVS) every year. Most of them however lackspectroscopic observations, which remains critical for a correctassignement of the variability type and for the understanding of theobject. Aims: The Variable Star One-shot Project (VSOP) is aimed at (1)providing the variability type and spectral type of all unstudiedvariable stars, (2) process, publish, and make the data available asautomatically as possible, and (3) generate serendipitous discoveries.This first paper describes the project itself, the acquisition of thedata, the dataflow, the spectroscopic analysis and the on-lineavailability of the fully calibrated and reduced data. We also presentthe results on the 221 stars observed during the first semester of theproject. Methods: We used the high-resolution echelle spectrographsHARPS and FEROS in the ESO La Silla Observatory (Chile) to survey knownvariable stars. Once reduced by the dedicated pipelines, the radialvelocities are determined from cross correlation with synthetic templatespectra, and the spectral types are determined by an automatic minimumdistance matching to synthetic spectra, with traditional manual spectraltyping cross-checks. The variability types are determined by manuallyevaluating the available light curves and the spectroscopy. In thefuture, a new automatic classifier, currently being developed by membersof the VSOP team, based on these spectroscopic data and on thephotometric classifier developed for the COROT and Gaia space missions,will be used. Results: We confirm or revise spectral types of 221variable stars from the GCVS. We identify 26 previously unknown multiplesystems, among them several visual binaries with spectroscopic binaryindividual components. We present new individual results for themultiple systems V349 Vel and BCGru, for the composite spectrum star V4385Sgr, for the T Tauri star V1045 Sco, andfor DM Boo which we re-classify as a BY Draconisvariable. The complete data release can be accessed via the VSOP website.Based on data obtained at the La Silla Observatory, European SouthernObservatory, under program ID 077.D-0085.
| The 74th Special Name-list of Variable Stars
We present the Name-list introducing GCVS names for 3153 variable starsdiscovered by the Hipparcos mission.
| New variable chemically peculiar stars identified in the HIPPARCOS archive
Since variability of chemically peculiar (CP) stars plays an importantrole for the astrophysical explanation of their outstanding behaviour,we have identified new variable CP stars listed in Renson's catalogueusing the extensive Hipparcos Variability Annex. From the 293 objectsfound, 33 were excluded because they are no CP stars and/or have noperiod listed, half of the remaining stars are newly identified and halfhad been already included in the catalogue of variable CP stars by\cite[Catalano & Renson (1997).]{Ca} Most of the newly identifiedvariability is due to an apparent magnetic field coupled with stellarrotation (oblique rotator model). The constraints of this model arefulfilled for all but three CP2 stars. Variations of bona fide Am-Fmstars are exclusively explained by eclipses of binary systems.Furthermore eight candidates of the >~mma Doradus group (pulsatingAm-Fm stars) were detected. Based on data from the ESA Hipparcosastrometry satellite. Table 1 is also available in electronic form atthe CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) orvia\break http://cdsweb.u-strasbg.fr/Abstract.html
| Walraven photometry of nearby southern OB associations
Homogeneous Walraven (VBLUW) photometry is presented for 5260 stars inthe regions of five nearby southern OB associations: Scorpio Centaurus(Sco OB2), Orion OB1, Canis Major OB1, Monoceros OB1, and Scutum OB2.Derived V and (B - V) in the Johnson system are included.
| Giant CP stars?
This study is part of an investigation of the possibility of usingchemically peculiar (CP) stars to map local galactic structure. Correctluminosities of these stars are therefore crucial. CP stars aregenerally regarded as main-sequence or near-main-sequence objects.However, some CP stars have been classified as giants. A selection ofstars, classified in the literature as CP giants, are compared to normalstars in the same effective temperature interval and to ordinary'nongiant' CP stars. No clear confirmation of a higher luminosity for'CP giants' than for CP stars in general is found. In addition, CPcharacteristics seem to be individual properties not repeated in acomponent star or other cluster members.
| The S201 far-ultraviolet imaging survey. III - A field in Sagittarius
Far-ultraviolet imagery of a 20 deg diameter field in Sagittarius,centered near (1950) R.A. 18 h 34 m, decl. -30 deg 25 arcmin, wasobtained by the S201 far-ultraviolet camera during the Apollo 16mission. In a 10-minute exposure covering the 1250-1600 A wavelengthrange, 1034 star images are detectable, with a limiting ultravioletmagnitude of about 10. Most of these objects are identified withearly-type stars listed in the Smithsonian Astrophysical ObservatoryStar Catalog, the Catalog of Stellar Identifications, or both, but 203objects remain unidentified or are identified with late-type stars. Thephotometric measurements appear to be in reasonable agreement with thoseof the International Ultraviolet Explorer for stars in common, and withexpectations for A0 stars. A detailed photometric study was made of theMessier 8 region, and it is concluded that dust-scattered starlightcontributes about half of the total radiation observed from the centralregion of M8.
|
Додај нови чланак
Линкови у сродству са темом
Додај нови линк
Чланови следећих група \:
|
Посматрања и Астрометриски подаци
| Сазвежђа: | Јужна круна |
| Ректацензија: | 18h21m14.41s |
| Deклинација: | -39°01'18.3" |
| Apparent магнитуда: | 6.794 |
| Даљина: | 182.149 parsecs |
| Proper motion RA: | -16.3 |
| Proper motion Dec: | -21.1 |
| B-T magnitude: | 6.939 |
| V-T magnitude: | 6.806 |
Каталог и designations:
|
