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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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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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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UBV Photoelectric Photometry Catalogue (1986). III Errors and Problems on DM and HD Stars
Not Available
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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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On absorption by hot interstellar gas. II - The 5303-A forbidden line of Fe XIV
Spectroscopic observations of 29 stars at 5303 A obtained with the coudespectrograph on the 2.7-m reflector at McDonald Observatory during1979-1983 are reported. Instrumental FWHM resolution is 27, 54, or 10pm, and detection limits near 100 fm equivalent width are obtained inoptimal cases. The results are presented in tables and a diagram. Noabsorption attributable to Fe XIV in hot interstellar gas is detectedexcept for HD 93521, on Apr. 10, 1981, only. This absorption can belocated either in interstellar gas at 1.2 million K or less with an FeXIV/Fe X ratio greater than 3 or in hot gas confined in an inhomogeneousstellar corona.
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On absorption by hot interstellar gas. I - Forbidden Fe X 6375
The spectra of 32 stars have been observed in the region of the coronalforbidden Fe X 6375 line at detection limits near an equivalent width of1 mA in the best cases. No absorption which can be attributed to Fe Xions in hot interstellar gas is seen in any of these spectra except one,in general agreement with predictions based on a three-phase model ofthe interstellar medium. Toward Cephei an absorption line is measuredwith an equivalent width of 8.1 + or - 2 mA, a width corresponding to 20+ or - 5 km/s or a temperature not greater than about (0.5 + or - 0.25)x 10 to the 6th K, and, if it is caused by Fe X ions, a radial velocityof -355 km/s. On that hypothesis, the hot interstellar gas constitutesat least 30 percent of the column density of gas along this light path.Six new telluric lines also are detected, and the 6376, 6379 A diffuseinterstellar bands are observed toward all six appreciably reddenedstars and one high-latitude star.
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Ultraviolet extinction and diffuse band strength correlations
Correlations between UV extinction parameters and diffuse band strengthsare south, using a data base of 50 stars with recently measuredextinction curves. A novel aspect of this study is that the basicdependence of most interstellar parameters on E(B-V) (or, nearlyequivalently, on the total hydrogen column density) has been largelycanceled out. After this cancellation, a weak correlation is foundbetween the 4430 A diffuse band and the 2175 A extinction feature. Noother correlations are found. These results support a molecular originfor the 5780 A and 6284 A bands. It is speculated that the correlationpattern found for the 4430 A band can be explained if this bandoriginates in reactions on disordered grain surfaces.
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High velocity gas associated with supernova remnants
High dispersion International Ultraviolet Explorer spectra of early typebackground stars were obtained. An analysis was made of absorption linesoriginating in gas associated with the remnant S147 and the detection ofgas associated with the remnant IC443. In the star HD 36665 behind S147,high velocity lines and low velocity interstellar CO was detected,probably originating in gas associated with the remnant.
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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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Spectroscopic observations of stars in HII regions.
Not Available
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Error analysis of the photoelectric catalogue
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1973A&AS....9..297F&db_key=AST
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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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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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Polarization of Stellar Radiation. III. The Polarization of 841 Stars.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1951ApJ...114..241H&db_key=AST
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A Finding List of O and B Stars of High Luminosity.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1951ApJ...113..141N&db_key=AST
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