Total to Selective Extinction Ratios and Visual Extinctions from Ultraviolet Data
We present determinations of the total to selective extinction ratio R_Vand visual extinction A_V values for Milky Way stars using ultravioletcolor excesses. We extend the analysis of Gnacinski and Sikorski (1999)by using non-equal weights derived from observational errors. We presenta detailed discussion of various statistical errors. In addition, weestimate the level of systematic errors by considering differentnormalization of the extinction curve adopted by Wegner (2002). Ourcatalog of 782 R_V and A_V values and their errors is available in theelectronic form on the World Wide Web.
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High-velocity NaI and CaII absorption components observed towards the IC 443 SNR
We present high-resolution spectra (R ~ 1.8 km s-1) of theinterstellar NaI and CaII interstellar absorption lines observed towards4 early-type stars with distances of 900-1500 pc in the line-of-sighttowards the IC 443 Supernova Remant (SNR). The spectra of two of thesestars (HD 43582 and HD 254577) exhibit a very complex pattern ofabsorption with cloud components covering a total velocity range of -100km s-1 to +50 km s-1. The relative absorptionstrength of many of the higher velocity components is highly variablebetween these two stars, suggesting that the disturbed interstellar gasin this region possesses significant density gradients and/or largedifferences in ionization and element depletion. In addition, we havedetected three additional high-velocity components at Vhelio= -97.5, -84.0 and -67.6 km s-1 solely in their CaII lines,suggesting that the very highest velocity gas is more ionized and/orwarmer than the lower velocity components or it has a highly variablelevel of gas phase element abundances.The column density ratios of NaI/CaII for the higher velocity cloudcomponents are all <0.2, which is consistent with appreciable levelsof dust grain destruction due to interstellar shocks caused byinteraction of the expanding SNR blast-wave with the ambientinterstellar medium. The distance to IC 443 is confirmed at ~ 1500 pc,which places the remnant at a similar distance to the Gem OB1 stellarassociation. Finally we note that the model of Chevalier (1999), inwhich the SNR is expanding into a clumpy interstellar medium, can bestreproduce the observed patterns of both emission and absorption.
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The total-to-selective extinction ratio determined from near IR photometry of OB stars
The paper presents an extensive list of the total to selectiveextinction ratios R calculated from the infrared magnitudes of 597 O andB stars using the extrapolation method. The IR magnitudes of these starswere taken from the literature. The IR colour excesses are determinedwith the aid of "artificial standards" - Wegner (1994). The individualand mean values of total to selective extinction ratios R differ in mostcases from the average value R=3.10 +/-0.05 - Wegner (1993) in differentOB associations. The relation between total to selective extinctionratios R determined in this paper and those calculated using the "methodof variable extinction" and the Cardelli et al. (1989) formulae isdiscussed. The R values presented in this paper can be used to determineindividual absolute magnitudes of reddened OB stars with knowntrigonometric parallaxes.
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Classification and properties of UV extinction curves
The catalog of Savage et al. (\cite{ref27}) reporting colour excesses of1415 stars from ANS photometry offers the opportunity to deeplyinvestigate the characteristics of UV extinction curves which differfrom the standard extinction of the diffuse interstellar medium. To thisaim we have selected a sample of 252 curves, which have been comparedwith the relations derived by Cardelli et al. (\cite{ref4}; CCM in thefollowing) for a variety of R_V values in the range 2.4-5 and have beenclassified as normal if they fit at least one of the CCM curves oranomalous otherwise. We find that normal curves with small R_V are justas numerous as those with large R_V. The anomalous objects are arrangedinto two groups according to the strength of the bump at 0.217 mu . Fora given value of c_2 this increases along the sequence: type Aanomalous, normals and type B anomalous, suggesting that this sequenceshould correspond to an increase of the amount of small grains along thesightline. Considerations concerning the environmental characteristicsindicate that the anomalous behaviour is not necessarily tied to theexistence of dense gas clouds along the line of sight.
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UBV beta Database for Case-Hamburg Northern and Southern Luminous Stars
A database of photoelectric UBV beta photometry for stars listed in theCase-Hamburg northern and southern Milky Way luminous stars surveys hasbeen compiled from the original research literature. Consisting of over16,000 observations of some 7300 stars from over 500 sources, thisdatabase constitutes the most complete compilation of such photometryavailable for intrinsically luminous stars around the Galactic plane.Over 5000 stars listed in the Case-Hamburg surveys still lackfundamental photometric data.
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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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Fabry-Pero image of shocked H2 emission in IC 443
We obtained an H2 1-0 S(1) image of the south-east ridge in thesupernova remnant IC 443 by using a Fabry-Perot imager. The H2 emittingregion was resolved into many clumps which has not been seen by previousobservations with larger beams. The H2 image was compared with a 21-cm HI map in order to investigate the H2 excitation mechanism. Although theH2 emitting area roughly overlaps the H I area, no one-to-onecorrelation between the peaks of H2 and H I is found. This morphologyindicates that although the H I 21-cm line is due to moleculardissociation by J-shocks, the H2 emission peaks are caused by C-shocksin dense clumps. Consequently, the coexistence of C-shocks and J-shocksis suggested to be present at the molecular ridge of IC 443.
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An Einstein Observatory SAO-based catalog of B-type stars
About 4000 X-ray images obtained with the Einstein Observatory are usedto measure the 0.16-4.0 keV emission from 1545 B-type SAO stars fallingin the about 10 percent of the sky surveyed with the IPC. Seventy-fourdetected X-ray sources with B-type stars are identified, and it isestimated that no more than 15 can be misidentified. Upper limits to theX-ray emission of the remaining stars are presented. In addition tosummarizing the X-ray measurements and giving other relevant opticaldata, the present extensive catalog discusses the reduction process andanalyzes selection effects associated with both SAO catalog completenessand IPC target selection procedures. It is concluded that X-rayemission, at the level of Lx not less than 10 exp 30 ergs/s, is quitecommon in B stars of early spectral types (B0-B3), regardless ofluminosity class, but that emission, at the same level, becomes lesscommon, or nonexistent, in later B-type stars.
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The diffuse interstellar bands. VI - New features near 6800 A
A group of about 29 weak lines lying between 6767 and 6862 A has beenfound on high signal-to-noise ratio (S/N) scans of reddened stars. Theyhave been observed in stars between types O3 and A5, do not appear inunreddened stars of those types observed with the same equipment, andstrengthen with icreasing E(B-V). For these reasons, they are believedto be interstellar. Although narrow, they are not perfectly sharp at aresolution of 35,000. Five or six of the stronger features are nearlyuniformly spaced at intervals of 35/cm, which is suggestive of thespacing expected for rotational structure of light hydrides such as CH,NH and OH, but no plausible carrier of those species has beenidentified.
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The interstellar 217 NM band - A third catalogue of equivalent widths
A catalog of equivalent widths of the 217 nm interstellar absorptionband as well as other parameters characterizing the extinction curve inthe ultraviolet has been compiled for 790 O and B stars. A relativelytight correlation between the equivalent width of the 217 nm band andE(B-V) indicates that the absorber of this band is connected with thepopulation of larger interstellar grains responsible for the visualextinction. The parameter characterizing the amount of extinction in thefar UV is only weakly correlated with E(B-V), a result in accord withthe assumption that a second population of very small grains causes therapid increase of the far-UV extinction.
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The structure and dynamics of evolved supernova remnants - The IC 443 complex
The extended cloud complex containing the supernova remnant IC 443, theH II region S 249 and members of the Gem OB 1 association is studiedwith IRAS observations at 12, 25, 60 and 100 microns and WSRTobservations at 327 and 1400 MHz and in the 21 cm H I line. IC 443 isshown to consist of three interconnected approximately sphericalsubshells of vastly different radii and centroids. The geometry is fullyconstrained by the structural and kinematic data. Two of these subshellstogether define the usually assumed boundaries of IC 443, while thethird includes the optical filaments which extend beyond the brightnorth-eastern rim. These filaments are shown to have well correlatednonthermal radio counterparts. Physical parameters are derived for theentire complex, individual H II regions and the shocked and recombinedgas within IC 443 from the radio and infrared data. The availableevidence implies that the SNR shock has encountered a pre-existing highdensity shell. It is shown that the system of subshells is fullyconsistent with formation by stellar wind driven bubbles generated byassociation members within the inhomogeneous environment of the complex.
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A catalog of ultraviolet interstellar extinction excesses for 1415 stars
Ultraviolet interstellar extinction excesses are presented for 1415stars with spectral types B7 and earlier. The excesses with respect to Vare derived from Astronomical Netherlands Satellite (ANS) 5-channel UVphotometry at central wavelengths of approximately 1550, 1800, 2500, and3300 A. A measure of the excess extinction in the 2200-A extinction bumpis also given. The data are valuable for investigating the systematicsof peculiar interstellar extinction and for studying the character of UVinterstellar extinction in the general direction of stars for which theextinction-curve shape is unknown.
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Star-forming regions near the supernova remnant IC 443
The supernova remnant (SNR) IC 443 (3C 157), along with W28, W44, S147,and HB 21, represents a growing number of examples where SNRs appear tohave collided with nearby molecular clouds or are surrounded by denseshells of neutral hydrogen. In the case of W28, far-infraredobservations have shown that a massive, O-type star and possibly apre-main-sequence B-type star are associated with the molecular cloudand its environment. In the current study, the northern component of theIC 443 molecular cloud has been detected at 20, 27, and 93 microns bythe Far Infrared Sky Survey Experiment. The bolometric luminosity ofthis far-infrared source is about 130 solar luminosities, consistentwith the expected luminosity of a B7 V star. From the far-infrared andradio observations the energetics of this region is described andcompared with other known examples of SNR/molecular cloud associations.These findings are also discussed in the context of theoretical modelswhere SNRs trigger star-forming activity in nearby molecular clouds.
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Studies of luminous stars in nearby galaxies. I. Supergiants and O stars in the Milky Way.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1978ApJS...38..309H&db_key=AST
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Infrared colors and the diffuse interstellar bands
Broad-band infrared photometric measurements have been gathered for 105stars which exhibit diffuse interstellar bands in their spectra. Allnormal stars obey a single reddening law, and a value of R equal to 3.08+ or - 0.15 is derived. This value is consistent with other recentdeterminations of R. The diffuse band indicators, the central depth ofthe 4430-A feature and the equivalent widths of the 5780-A and 6284-Afeatures, show as large a scatter with the infrared color excesses asthey do with E(B - V). No single-valued relation between the colorexcesses and the diffuse band strengths appears to exist. This castsdoubt on whether dust grains which produce the visual and infraredextinctions are the carriers for the diffuse interstellar features.
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The diffuse interstellar bands. IV - The region 4400-6850 A
It is shown that 39 diffuse bands lying between 4400 and 6850 A can beregarded as certainly or probably interstellar bands. Of these, 24 bandsare described in detail. These, and seven additional features which maybe interstellar are tabulated. For those 17 bands for which the data aremost extensive, the correlation of equivalent width with the colorexcess ranges from good to excellent when regional effects and errors ofobservation are taken into consideration. To a good first approximation,the entire diffuse line spectrum strengthens together with and in directproportion to increasing interstellar extinction. This result supportsthe hypothesis that the diffuse lines can properly be regarded as finestructure in the interstellar extinction curve.
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Spectroscopic observations of stars in HII regions.
Not Available
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A Study of the i Geminorum Association.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1960ApJ...132..361H&db_key=AST
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A Catalogue of H II Regions.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1959ApJS....4..257S&db_key=AST
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A study of the I GEM association.
Not Available
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Studies in Galactic STRUCTURE.II.LUMINOSITY Classification for 1270 Blue Giant Stars.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1955ApJS....2...41M&db_key=AST
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The Association i Geminorum.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1955ApJ...121...24C&db_key=AST
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Studies of Faint B-Type Stars.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1950ApJ...111..495P&db_key=AST
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