Contents
Images
Upload your image
DSS Images Other Images
Related articles
Observations towards early-type stars in the ESO-POP Survey - II. Searches for intermediate- and high-velocity clouds
We present CaII K and TiII optical spectra of early-type stars takenmainly from the ultraviolet and visual echelle spectrograph (UVES)Paranal Observatory Project, plus HI 21-cm spectra, from the Vila-Elisaand Leiden-Dwingeloo Surveys, which are employed to obtain distances tointermediate- and high-velocity clouds (IHVCs). HI emission at avelocity of -117 kms-1 towards the sightline HD30677 () withcolumn density ~1.7 × 1019 cm-2 has nocorresponding CaII K absorption in the UVES spectrum, which has asignal-to-noise ratio (S/N) of 610 per resolution element. The star hasa spectroscopically determined distance of 2.7 kpc, and hence sets thisas a firm lower distance limit towards Anti-Centre cloud ACII. Towardsanother sightline (HD46185 with ), HI at a velocity of +122kms-1 and column density of 1.2 × 1019cm-2 is seen. The corresponding CaII K spectrum has a S/N of780, although no absorption is observed at the cloud velocity. Thissimilarly places a firm lower distance limit of 2.9 kpc towards thisparcel of gas that may be an intermediate-velocity (IV) cloud. The lackof IV CaII absorption towards HD196426 () at a S/N of 500 reinforces alower distance limit of ~700 pc towards this part of complex gp, wherethe HI column density is 1.1 × 1019 cm-2 andvelocity is +78 kms-1. Additionally, no IV CaII is seen inabsorption in the spectrum of HD19445, which is strong in HI with acolumn density of 8 × 1019 cm-2 at avelocity of ~ -42 kms-1, placing a firm althoughuninteresting lower distance limit of 39 pc to this part of IV South.Finally, no high-velocity CaII K absorption is seen towards HD115363 ()at a S/N of 410, placing a lower distance of ~3.2 kpc towards the HVCgas at velocity of ~ +224 kms-1 and HI column density of 5.2× 1019 cm-2. This gas is in the same regionof the sky as complex WE (Wakker 2001), but at higher velocities. Thenon-detection of CaII K absorption sets a lower distance of ~3.2 kpctowards the HVC, which is unsurprising if this feature is indeed relatedto the Magellanic System.
| Pulkovo compilation of radial velocities for 35495 stars in a common system.
Not Available
| Early-type stars observed in the ESO UVES Paranal Observatory Project - I. Interstellar NaI UV, TiII and CaII K observations*
We present an analysis of interstellar NaI (λair=3302.37 and 3302.98 Å), TiII(λair= 3383.76Å) and CaII K (λair= 3933.66 Å) absorptionfeatures for 74 sightlines towards O- and B-type stars in the Galacticdisc. The data were obtained from the Ultraviolet and Visual EchelleSpectrograph Paranal Observatory Project, at a spectral resolution of3.75 km s-1 and with mean signal-to-noise ratios per pixel of260, 300 and 430 for the NaI, TiII and CaII observations, respectively.Interstellar features were detected in all but one of the TiIIsightlines and all of the CaII sightlines. The dependence of the columndensity of these three species with distance, height relative to theGalactic plane, HI column density, reddening and depletion relative tothe solar abundance has been investigated. We also examine the accuracyof using the NaI column density as an indicator of that for HI. Ingeneral, we find similar strong correlations for both Ti and Ca, andweaker correlations for Na. Our results confirm the general belief thatTi and Ca occur in the same regions of the interstellar medium (ISM) andalso that the TiII/CaII ratio is constant over all parameters. We henceconclude that the absorption properties of Ti and Ca are essentiallyconstant under the general ISM conditions of the Galactic disc.
| The First Ultraviolet and Optical Spectropolarimetry of the B[e] Star HD 50138
We report the first ultraviolet spectropolarimetry of the B[e] star HD50138, obtained with the Wisconsin Ultraviolet Photo-PolarimeterExperiment aboard the Astro-2 Space Shuttle mission in 1995 March. Thedata cover the spectral range 1500-3200 Å. Spectropolarimetryobtained contemporaneously in the range of 3800-10,000 Å in thevisual-to-near-IR region are presented as well. The presence ofintrinsic polarization is detected from the UV to the near-IR. Strongevidence of a thin gaseous disk around the star is found. An almost flatwavelength dependence of the intrinsic polarization in the opticalspectral region indicates that electron scattering, rather than dustscattering, is the dominant polarizing mechanism, although a smallcontribution due to dust scattering cannot be completely ruled out. Asmall inclination of the disk away from edge-on with respect to the lineof sight is suggested. Comparison with similar polarimetric observationsobtained for different objects that have the same circumstellar geometryshows that the envelope of HD 50138 probably has a rather large densitycontrast between the equatorial and polar regions that does not producea position angle flip like that observed in other objects, notably HD45677.
| Ultraviolet and Visible Spectropolarimetry of the Red Rectangle and HD 44179
We present the first ultraviolet and visible spectropolarimetry of thebiconical nebula the Red Rectangle and its associated binary HD 44179.These observations were made between 1992 November and 1995 Novemberusing the Faint Object Spectrograph on board the Hubble Space Telescopeand two separate ground-based observations. These new data gives moreclues to the geometrical picture of the region. Previous results havetypically reported linear polarizations in the visible and infrared of1%--2%. We present results that clearly show an increase in thecontinuum polarization shortward of 2000 A into the 10%--15% range. Inaddition, the position angle is seen to rotate by 65 deg in the samewavelength region, probably a result of the bipolar geometry and theexistence of an optically thick equatorial disk. It is also seen thatlines due to Mg II absorption, H alpha emission, and several lines dueto CO are polarized differently than the continuum. There also appear tobe features attributable to OH, which would be extremely unusualconsidering the assumed carbon-rich atmosphere that is present.
| 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.
| Broad-band photometry of selected southern ultraviolet-bright stars.
Not Available
| Catalog of O-B stars observed with Tokyo Meridian Circle
A catalog of the O-B stars, selected from 'Blaauw-Parenago' list andRubin's catalog, has been compiled on the FK4 system by the observationsmade with Gautier 8-inch Meridian Circle at the Tokyo AstronomicalObservatory during the period, 1971 to 1979. It contains 1059 stars andwas compiled for the future establishment of high precision propermotions of O-B stars.
| A survey of ultraviolet objects
An all-sky survey of ultraviolet objects is presented together with astatistical analysis that leads to the conclusion that there is asignificantly higher population of hot subdwarfs lying below themain-sequence than hitherto thought. The distribution of all ultravioletobjects, main sequence ultraviolet objects, and MK unclassifiedultraviolet objects are shown in galactic coordinates, and the absolutemagnitudes and color-color diagrams for these groups are presented.Scale heights are derived, giving values similar to planetary nebulaefor the hottest groups.
| Optical observations of ultraviolet objects. I - Spectral classification of 103 stars /l = 200-275 deg/
Results are presented of a program of spectral classification of 103stars originally selected as ultraviolet objects from TD-1 satellitephotometry with the S2/68 experiment. Most of the objects appear to bespectroscopically normal stars; the method of selection yielded a sampleof relatively unreddened B stars at distances up to about 2 kpc. Thisresult is compared with recent studies of the spatial distribution ofinterstellar extinction in the same regions of the sky.
| Spectral classification from the ultraviolet line features of S2/68 spectra. V - Supplement series
The paper presents the ultraviolet classification of more than 450 B-Aand F spectra obtained with the sky survey telescope mounted on the TD1satellite. Concerning abnormal objects, attention is given to the Bestars, the binary stars, the helium weak stars, and the lambda Booobjects. With regard to Be stars, it is concluded that the 1930 Awavelength feature is linked to the existence of either shell structuresor Fe II emission lines in the visual spectral range. In addition, it issuggested that stellar spectra at wavelengths of 1410, 1610-20 and 2400A are equivalent to the He-weak group in the classical range.
| A method for identifying high-velocity OB stars.
Not Available
| The Radial Velocities of Faint Class B Stars in the Declination Zone 0° to -23°.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1943ApJ....97..300N&db_key=AST
|
Submit a new article
Related links
Submit a new link
Member of following groups:
|
Observation and Astrometry data
| Constellation: | Großer Hund |
| Right ascension: | 06h31m24.24s |
| Declination: | -12°33'34.9" |
| Apparent magnitude: | 6.781 |
| Distance: | 450.45 parsecs |
| Proper motion RA: | -4 |
| Proper motion Dec: | -2 |
| B-T magnitude: | 6.585 |
| V-T magnitude: | 6.765 |
Catalogs and designations:
|
INHABITED SKY
