|Merged catalogue of reflection nebulae|
Several catalogues of reflection nebulae are merged to create a uniformcatalogue of 913 objects. It contains revised coordinates,cross-identifications of nebulae and stars, as well as identificationswith IRAS point sources.The catalogue is only available in electronic form at the CDS viaanonymous ftp to cdsarc.u-strasbg.fr (18.104.22.168) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/399/141
|The Nature of Peculiar Stellar Complexes|
The nature of stellar complexes with peculiar populations andmorphologies is investigated. The existence in the LMC of complexes madeup of isolated stars, on the one hand, and consisting exclusively ofclusters, on the other hand, could be due to different turbulencepatterns in the initial gaseous medium. Arc-shaped stellar complexes areunlikely to be the result of star formation in a gaseous shell swept upby a central source of pressure, and instead probably reflect the shapeof a bow shock that develops when a sufficiently dense cloud is subjectto dynamical pressure. A peculiar arc-shaped complex in NGC 6946, whichcontains a young, massive cluster, may be the result of an obliqueinfall of a high-velocity cloud onto a region of the gaseous disk of theGalaxy with a strong, regular magnetic field; the properties of thiscomplex can be explained as the result of a collision of the resultingshocks. The arc-shaped complexes in the LMC were also probably producedby high-velocity clouds moving obliquely through the more tenuous gas ofthe LMC disk. A similar complex in NGC 300 may owe its origin to theeffect produced on a dense cloud by the shock from an extremely powerfulexternal explosion, whose stellar remnant may have survived as an X-raysource now located along the line of symmetry of the arc of the complex.The rareness of such structures can be explained by the narrow range ofconditions under which they can develop.
|The Secret Inner Life of the Orion Nebula|
Beneath the familiar surface of the Orion Nebula is a spectacularmolecular hydrogen outflow from a young stellar object, of very unusualmorphology. In this paper I briefly discuss this outflow, its possibleorigins, and its interaction with the Nebula.
|Dusty Plasmas in Interstellar Clouds and Star Forming Regions|
|The Orion OB1 association. 1: Stellar content|
Walfraven photometry of established and probable members of the OrionOB1 association is presented. Effective temperature, surface gravity,luminosity and mass are derived for all stars, using atmosphere model byKurucz (1979). Absolute magnitudes are calculated using the Straizys andKuriliene (1981) tables. Distance moduli and visual extinctions aredetermined. A comparison of the visual extinctions to IRAS 100micrometers data shows that the near edge of the Orion A and B cloudslies at a distance of approximately 320 pc, while the far edge is atapproximately 500 pc. A method for deriving the ages of the subgroups bycomparing theoretical isochrones to the observations in the log g, logTeff plane is presented. The derived ages suggest, contraryto earlier studies, that subgroup 1b is younger than 1c, which canpossibly be explained by past geometries of the system of stars and gas.The initial mass function for Orion OB1 is derived with the aid of theKolmogorov-Smirnoff test. Through extensive simulations, we show that itis very difficult to derive accurately the Initial Mass Function (IMF)from the available data. To within somewhat weak limits the IMF is foundto be of the form xi(log M) = AM-1.7 +/- 0.2 for allsubgroups. The energy output of the subgroups in the form of stellarwinds and supernovae is calculated and compared to the observed size andexpansion velocity of the Orion-Eridanus bubble. It is shown that theenergy output of the association can account for the morphology andkinematics of the interstellar medium (ISM).
|The large system of molecular clouds in Orion and Monoceros|
Emission is noted over about one-eighth of an 850-sq deg region centeredon Orion and Monoceros that has been surveyed in the J = 1 to 0 line ofCO; most of the emission arises from giant molecular clouds associatedwith Orion A and B, and Mon R2. A much smaller area was surveyed forC-13O emission. A comparison of cloud masses obtained by threeindependent methods indicates that CO luminosity is as accurate ameasure of cloud mass as other indicators. The possible relationshipsamong clouds in the survey are discussed, including the conjecture thatthe overall Orion complex of clouds is a much larger system thanpreviously considered, incorporating most of the clouds in the presentsurvey.
|One-millimeter continuum observations of IRAS and FIRSSE sources|
New 1 mm observations of galactic and extragalactic objects partlycontained in the FIRSSE and IRAS surveys are reported. Dusttemperatures, FIR wavelength dependence of dust opacity, and FIRluminosities of the observed sources are derived.
|A catalogue of bright nebulosities in opaque dust clouds|
Abstract image available at:http://adsabs.harvard.edu/abs/1977A&AS...29...65B
|Radio Emission from Small Galactic Nebulae at 606 MHz|
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1972AJ.....77..115T&db_key=AST
|Untersuchungen über Reflexionsnebel am Palomar Sky Survey I. Verzeichnis von Reflexionsnebeln|
|Studies of bright diffuse galactic nebulae with special regard to their spatial distribution.|
|Photographic studies of nebulae. III.|