Molecular Clouds Toward a New OB Association in Pup-CMa
We have mapped 16 molecular clouds toward a new OB association in thePup-CMa region to derive their physical properties. The observationswere carried out in the 12CO (J = 1 0) line with the Southernmillimetre-wave Telescope at Cerro Tololo, Chile. Distances have beendetermined kinematically using the rotation curve of Brand with Rȯ= 8.5 kpc and Vȯ = 220 km/s. Masses have been derived adopting a COluminosity to H2 conversion factor X = 3.8 . 1020 molecules cm-2 (Kkm/s)-1. The observed mean radial velocity of the clouds is comparablewith the mean radial velocity of stars composing an OB association inPup-CMa; it is in favor of the close connection of clouds with thesestars.
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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 (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/399/141
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Velocity Distribution of Stars in the Pup-CMa Association
The distribution of proper motions of stars in the Pup-CMa associationis presented. The stars' velocities are approximately parallel to eachother, which indicates that the stars are close together in space. Themutual distribution of stars and molecular clouds in the association isinterpreted as proof that the stars emerged from a single giganticprimordial molecular cloud (or several large clouds), destroyed byradiation and/or stellar wind coming from those stars. It is assumedthat part of that cloud is being dissipated, while part is being brokeninto several small clouds, which we are observing at present.
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New OB-Association in Pup - CMA
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Derivation of the Galactic rotation curve using space velocities
We present rotation curves of the Galaxy based on the space-velocitiesof 197 OB stars and 144 classical cepheids, respectively, which rangeover a galactocentric distance interval of about 6 to 12kpc. Nosignificant differences between these rotation curves and rotationcurves based solely on radial velocities assuming circular rotation arefound. We derive an angular velocity of the LSR of{OMEGA}_0_=5.5+/-0.4mas/a (OB stars) and {OMEGA}_0_=5.4+/-0.5mas/a(cepheids), which is in agreement with the IAU 1985 value of{OMEGA}_0_=5.5mas/a. If we correct for probable rotations of the FK5system, the corresponding angular velocities are {OMEGA}_0_=6.0mas/a (OBstars) and {OMEGA}_0_=6.2mas/a (cepheids). These values agree betterwith the value of {OMEGA}_0_=6.4mas/a derived from the VLA measurementof the proper motion of SgrA^*^.
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The Velocity Field of the Outer Galaxy
Abstract image available at:http://adsabs.harvard.edu/abs/1993A&A...275...67B
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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.
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Broad-band photometry of selected southern ultraviolet-bright stars.
Not Available
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Kinematics of molecular clouds. II - New data on nearby giant molecular clouds
The best currently available data on positions, distances, andvelocities of giant molecular clouds within 3 kpc of the sun areanalyzed to yield a one-dimensional rms cloud-to-cloud velocitydispersion of 7.8 +0.6, -0.5. Velocity dispersion is defined here as theroot mean square of cloud peculiar velocities, a quantity which includessmall-scale streaming. It is argued that this value for the velocitydispersion is pausible, based on examples of clouds whose velocitiescannot be explained purely by galactic rotation. The mean motion ofnearby molecular clouds is drifting by about 4 km/s with respect to theLSR.
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New Herbig-Haro objects in star-forming regions
A list of 25 new Herbig-Haro objects, HH 58 to HH 82, in the Orionmolecular clouds and in southern molecular cloud complexes has beencompiled. CCD images in the S II 6717, 6731 forbidden lines arepresented for the objects, together with a few spectra and some IRobservations. The individual objects and, when identified, their energysources are discussed. HH 65 is located in the red lobe of the bipolaroutflow associated with the highly variable reflection nebula Re 50. HH67 is a 22-arcsec long sinusoidal jet. HH 68/69 consists of a long,linear chain of four HH knots. HH 72 emerges from a 120-solar luminosityIRAS source embedded in a Bok globule. HH 79 is the first HH objectdiscovered in the Ophiuchus clouds. HH 80/81 in Sagittarius are amongthe brightest HH objects known, have complex velocities, high excitationconditions and emerge from a 6000-solar luminosity young B-star. HH 82is associated with the bright variable star S Coronae Australis.
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The velocity field of the outer Galaxy in the Southern Hemisphere. II - CO observations of galactic nebulae
CO observations of 308 objects (77 percent) from a catalogue (Brand etal., 1985) of galactic emission and reflection nebulae are presented; COwas detected in the direction of 234 nebulae (76 percent). For 194 ofthese objects (63 percent) the emission could actually be associatedwith the nebula. Fifteen objects (5 percent) have associated CO emissionwith velocity in excess of 50 km/s (VLSR). These objects areof crucial importance as they are potentially very distant, and nearlyall of them have been newly identified. In the course of this surveyseveral sources with interesting line profiles were found. Eighteen ofthem exhibit wings and/or plateaus and are potential CO outflow sources.
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The velocity field of the outer Galaxy in the Southern Hemisphere. I - Catalogue of nebulous objects
A multifrequency program to measure the velocity field of the outerGalaxy in the Southern Hemisphere (l = 230-305 deg) is outlined. Thispaper, the first in a series, presents a catalog of HII regions andreflection nebulae used as a basis for the study. Most of the entriesare previously uncatalogued; the emphasis is on small objects likely tobe very distant from the sun.
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Near-infrared observations of trapezium-type multiple systems Catalogue of observations and a new determination of the reddening law
Results are presented from a large scale near-infrared survey of smallsky areas of the Milky Way containing trapezium-type multiple starsystems located within young galactic clusters, H II regions or darknebulosities. Photometric maps at wavelength 2.2 microns complemented bybroadband JHKL photometry of the majority of the sources detected and ofthe star members of the systems were obtained. A number of randomlychosen comparison regions along the galactic plane were also mapped andthe results were also used, with recent semi-empirical models, todetermine the number of field stars expected for the program surveys.Analyses of the infrared two-color diagrams provide determinations ofthe values of the color excess ratios E(J-H)/E(H-K), E(H-K)/E(K-L) andE(J-K)/E(K-L). The resulting reddening law is found to differsignificantly from that in the direction of the Ophiuchus and Taurusdark clouds and possibly towards the Galactic Center.
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Molecular clouds associated with reflection nebulae. I - A survey of carbon monoxide emission
The paper presents 2.6 mm wavelength CO and (C-13)O observations of 130molecular clouds associated with reflection nebulae. Enhanced COemission was found in the vicinity of the illuminating star in abouthalf the objects studied. There is a tendency for the CO peak to beslightly displaced from the star. Many examples of peaks that appear toresult from heating of the cloud by the nearby star are found, whileothers appear to be associated with independent concentrations ofmaterial.
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Spectral types for early-type stars observed by SKYLAB
MK spectral types are presented for 246 early-type stars observed withthe S-019 ultraviolet stellar astronomy experiment on Skylab. K-linetypes are also given where applicable, and various peculiar stars areidentified. The peculiar stars include five silicon stars, a shell star,a helium-rich star, a silicon-strontium star, a chromium-europium star,and two marginal metallic-line stars.
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Stars in reflection nebulae
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1968AJ.....73..233R&db_key=AST
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A study of reflection nebulae.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1966AJ.....71..990V&db_key=AST
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TThe source of luminosity in galactic nebulae.
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