Upload your image
DSS Images Other Images
Submit a new article
|Optical polarimetry of infrared excess stars|
We present UBRVI polarimetry measurements for a group of 38 IRASinfrared excess stars and complement these observations with V-band datataken from the literature for 87 additional objects. After correctingthe observed values by the interstellar contribution, we find that 48%of the analyzed sample has polarization excess. In addition, thepolarization of these stars may correlate with infrared color excesses,particularly at 60 and 100 μm. We caution, however, that poor IRASdata quality at longer wavelengths affects this correlation. We analyzethe wavelength dependence of the linear polarization of 15 polarizedobjects in relation to Serkowski's empirical interstellar law. We findthat for 6 to 7 objects (depending on the interstellar model) themeasured polarization differs significantly from the empiricalinterstellar law, suggesting an intrinsic origin. We analyze thepolarimetry distribution of IRAS infrared excess objects in relation tothe Exoplanet host stars (i.e., stars associated with at least onelikely planetary mass object). The corresponding polarimetrydistributions are different within a high confidence level. Finally, wecompare the metallicity distributions of F and G IRAS infrared excess,Exoplanet host and field main sequence stars, and find that F-G IRASinfrared excess objects have metallicities quite similar (although notidentical) to field main sequence stars and significantly different fromthe Exoplanet host group.
|ICCD Speckle Observations of Binary Stars. XXIII. Measurements during 1982-1997 from Six Telescopes, with 14 New Orbits|
We present 2017 observations of 1286 binary stars, observed by means ofspeckle interferometry using six telescopes over a 15 year period from1982 April to 1997 June. These measurements constitute the 23dinstallment in CHARA's speckle program at 2 to 4 m class telescopes andinclude the second major collection of measurements from the MountWilson 100 inch (2.5 m) Hooker Telescope. Orbital elements are alsopresented for 14 systems, seven of which have had no previouslypublished orbital analyses.
|Candidate Main-Sequence Stars with Debris Disks: A New Sample of Vega-like Sources|
Vega-like sources are main-sequence stars that exhibit IR fluxes inexcess of expectations for stellar photospheres, most likely due toreradiation of stellar emission intercepted by orbiting dust grains. Wehave identified a large sample of main-sequence stars with possibleexcess IR radiation by cross-correlating the Michigan Catalog ofTwo-dimensional Spectral Types for the HD Stars with the IRAS FaintSource Survey Catalog. Some 60 of these Vega-like sources were not foundduring previous surveys of the IRAS database, the majority of whichemployed the lower sensitivity Point Source Catalog. Here, we providedetails of our search strategy, together with a preliminary examinationof the full sample of Vega-like sources.
|ICCD Speckle Observations of Binary Stars. XIII. Measurements During 1989- 1994 From the Cerro Tololo 4 M Telescope|
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1996AJ....111..936H&db_key=AST
|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.
|SAO stars with infrared excess in the IRAS Point Source Catalog|
We have undertaken a search for SAO stars with infrared excess in theIRAS Point Source Catalog. In contrast to previous searches, the entireIRAS (12)-(25)-(60) color-color diagram was used. This selection yieldeda sample of 462 stars, of which a significant number are stars withcircumstellar material. The stars selected can be identified aspre-main-sequence stars, Be stars, protoplanetary systems, post-AGBstars, etc. A number of objects are (visual) binary stars.Characteristic temperatures and IR excesses are calculated and theirrelations to spectral type are investigated.
|An optical search for Beta Pictoris-like disks around nearby stars|
A coronagraphic survey of more than one hundred stars has been carriedout in a search at optical wavelengths for circumstellar materialsimilar to that found in the Beta Pictoris disk. The survey stars wereprimarily dwarfs in the spectral range A to K and most were closer than100 pc. No evidence of circumstellar material was found around any ofthe stars, suggesting that Beta Pictoris is an abnormal object,surrounded by an unusually large amount of optically scatteringmaterial.
|Anomalous infrared emitters among A-type stars|
Spectroscopic observations of a sample of 26 stars have been analyzed inthe blue and near-IR to find out if anomalous IR emitters (AIEs) have aspectral signature. It is found that many, but not all, such starsexhibit shell characteristics. Analysis of available IRAS photometricobservations of A-type stars shows that the detection of circumstellarfeatures depends strongly on the number of IR bands at which the objectwas observed. Out of the 707 stars observed by IRAS, 41 AIEs, or 5.7percent, are found. Among nonsupergiant AIEs, 23 percent show shellfeatures. The true percentage of AIEs among A-type stars is estimated tobe 1.5 percent in a volume-corrected sample. A list of 24 stars whichwere apparently not previously detected as AIEs is given.
|Search for Beta Pictoris-like star|
The results are reported of a systematic search for Beta Pic-like stars,undertaken at ESO, CFHT and OHP. The candidate stars, either IRAS excessstars or shell stars, are investigated by means of high resolutionspectroscopy in the Ca II and Na I lines, which in the case of Beta Pic,are very peculiar. The observations are presented and it is shown thatamong the selected stars, few do show spectral similarities with BetaPic. Some interesting cases, HR10, HR2174, HR9043 and HR6519 arediscussed.
|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.
|Visual measurements of southern double stars|
A double-star observing program is described which has been started atCordoba with a 30 cm refractor. Usually neglected Index Catalog ofVisual Double Stars (IDS) pairs south of -60 deg are selected forobservation, most of them having been measured only one or two timespreviously. A total of 174 micrometric observations of 78 wide pairs arepresented together with a few measurements of 9 double stars not foundin the IDS. Also reported is a list of 135 additional measurements of 26test stars. By comparison with all earlier observations, an estimate forthe personal equation has been made, which is applied in combinationwith catalogue proper motions to investigate the nature of many of thesepairs.
|Micrometer measures of 401 double stars.|
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1972AJ.....77..878W&db_key=AST
Submit a new link
Member of following groups:
Observation and Astrometry data
|Proper motion RA:||-16.5|
|Proper motion Dec:||26.2|
Catalogs and designations: