The Disk and Environment of the Herbig Be Star HD 100546
Coronagraphic imaging of the nearest Herbig Be star with the SpaceTelescope Imaging Spectrograph (STIS) on board the Hubble SpaceTelescope, Ks (2.15 μm) imaging with ADONIS at the 3.6 m telescope atLa Silla, and mid-infrared imaging with OSCIR using the 4 m BlancoTelescope at Cerro Tololo Inter-American Observatory confirm thedetection of the disk reported by Pantin et al. and map the disk out to5" (~515 AU) in the optical and at Ks. While the source is unresolved at10 and 18 μm, it can be traced to 1.5" at 11.7 μm. We confirm thechange in the radial dependence of the disk surface brightness near 2.7"seen at 1.6 μm by Augereau et al. at Ks. No such break in the powerlaw is seen in the optical. The STIS data reveal spiral dark lanestructure, making HD 100546 the third near-zero-age main-sequence HerbigAe/Be star with structure more than 100 AU from the star. We alsooptically detect a low surface brightness envelope extending 10" (1000AU) from the star, in addition to nebulosity, which is probablyassociated with DC 292.6-7.9. The survival of the envelope throughessentially the entire pre-main-sequence lifetime of the star, coupledwith the absence of physical companions within 1500 AU of the star,suggests that envelope lifetimes owe more to the star-formingenvironment than to mass-loss activity from the Herbig Ae/Be star. Basedon observations made with the NASA/ESA Hubble Space Telescope, obtainedat the Space Telescope Science Institute, which is operated by theAssociation of Universities for Research in Astronomy, Inc., under NASAcontract NAS 5-26555. This study is part of the STIS IDT protoplanetarydisk Key Project. This work is also based on observations collected atthe European Southern Observatory, La Silla, Chile, Proposal ID63.I-0196. This work is also based on observations made at the CerroTololo Inter-American Observatory. CTIO is operated by AURA, Inc., undercooperative agreement with the National Science Foundation.
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Irregular variables of type Lb. Energy distributions and stellar parameters
AGB variables of types Lb, SRa, SRb, and Mira are studied by fittingcombinations of blackbodies to visual, near infrared and IRAS data. Thispaper supplements an earlier work dealing with a smaller sample of SRaand SRb variables. The fitted parameters T*, T dand Rd/R* are related to physically meaningfulquantities. Also, quantities derived from the fits like the ratio of theluminosities of the two fitted blackbodies are confronted withindependent mass-loss estimators. For the O-rich Lb variables all of the`blue' objects can be reasonably well approximated by only one blackbodywhereas the `red' ones need two. Among the `blue' objects a significantfraction seem to be not on the AGB at all but a kind of `RGB pollution'.The T* values, reflecting mainly offseted (-500 K) effectivetemperatures for objects with small to moderate mass-loss, aresignificantly higher in the `blue' cases. Carbon-rich objects differsignificantly from the O-rich ones in their fit parameters. Sometimes`unphysically' low T* are found - a result of circumstellarreddening in the high mass-loss cases. Furthermore lower values ofT d, accompanied by normal T*s and large shellradii are common and can be related to the phenomenon of detachedshells. S-stars populate a similar region to the optically thin carbonstars in their fit properties.
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Classification and Identification of IRAS Sources with Low-Resolution Spectra
IRAS low-resolution spectra were extracted for 11,224 IRAS sources.These spectra were classified into astrophysical classes, based on thepresence of emission and absorption features and on the shape of thecontinuum. Counterparts of these IRAS sources in existing optical andinfrared catalogs are identified, and their optical spectral types arelisted if they are known. The correlations between thephotospheric/optical and circumstellar/infrared classification arediscussed.
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Irregular variables of type Lb. New JHKL'M-photometry for 160 stars.
This paper presents new near infrared observations of 160 Irregularvariables of type Lb in the JHKL'M filter bands. These measurements aresupplemented by data for additional 56 stars taken from the literature.In total 220 datasets are available because of some multipleobservations. From our sample, 216 stars have near infrared (NIR)photometry now. Our sample of visually bright Lb-variables displays verysimilar infrared properties when compared with SRa- and SRb-variables.Derived from NIR-two colour diagrams the oxygen-rich Lbs seem to haveintermediate atmospheric conditions between Miras and normal giants.There may be a sligthly larger "contamination" with non AGB-giants thanin the case of the semiregulars. Using only our IR-colours the S- andthe Carbon-stars among the Lbs again are undistinguishable fromSR-variables of the same chemistry.
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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.
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IRAS catalogues and atlases - Atlas of low-resolution spectra
Plots of all 5425 spectra in the IRAS catalogue of low-resolutionspectra are presented. The catalogue contains the average spectra ofmost IRAS poiont sources with 12 micron flux densities above 10 Jy.
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Variable stars in the General Catalogue of Trigonometric Parallaxes
Not Available
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Luminosity and velocity distribution of high-luminosity red stars. III. Old-disk-population giants
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1973PASP...85..542E&db_key=AST
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59th Name-List of Variable Stars
Not Available
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The classification of intrinsic variables. IV. Very-small-amplitude, very-short-period red variables
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1973ApJ...184..793E&db_key=AST
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Narrow-Band and Broad-Band Photometry of Red Stars. III. Southern Giants
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1970ApJ...161..199E&db_key=AST
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Stellar groups, VI. Space motions of the dwarf A-type and giant M-type stars in the solar neighbourhood
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1960MNRAS.120..448E&db_key=AST
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Summary of the parallaxes of 130 stars.
Not Available
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NEWS@SKY (Science&Space News)
