HD 97048's Circumstellar Environment as Revealed by a Hubble Space Telescope ACS Coronagraphic Study of Disk Candidate Stars
We present the results of a coronagraphic scattered-light imaging surveyof six young disk candidate stars using the Hubble Space Telescope Advanced Camera for Surveys. The observations made use of the 1.8"occulting spot through the F606W (broad V) filter. Circumstellarmaterial was imaged around HD 97048, a Herbig Ae/Be star located in theChamaeleon I dark cloud at a distance of 180 pc. The material is seenbetween ~2" (360 AU) and ~4" (720 AU) from the star in all directions. A V-band azimuthally averaged radial surface brightness profile peaks atr=2'' with a value of 19.6+/-0.2 mag arcsec-2 andsmoothly decreases with projected distance from the star asI~r-3.3+/-0.5. An integrated flux of 16.8+/-0.1 mag ismeasured between 2" and 4", corresponding to a scattered-lightfractional luminosity lower limit ofLsca/L*>8.4×10-4. Filamentarystructure resembling spiral arms similar to that seen in Herbig Ae/Bedisks is observed. Such structure has been attributed to the influenceof orbiting planets or stellar encounters. Average surface brightnessupper limits are determined for the five nondetections: HD 34282, HD139450, HD 158643, HD 159492, and HD 195627. Possible reasons for thenondetections are disks that are too faint or disks hidden by theocculter.
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Early type high-velocity stars in the solar neighborhood. IV - Four-color and H-beta photometry
Results are presented from photometric obaservations in the Stromgrenuvby four-color and H-beta systems of early-type high-velocity stars inthe solar neighborhood. Several types of photometrically peculiar starsare selected on the basis of their Stromgren indices and areprovisionally identified as peculiar A stars, field horizontal-branchstars, metal-poor stars near the Population II and old-disk turnoffs,metal-poor blue stragglers, or metallic-line A stars. Numerousphotometrically normal stars were also found.
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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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Kinematical studies of open clusters and OB-associations from relative radial velocity observations. II - The Orion Belt region
Relative radial velocities have been obtained for 66 stars of theclustering Cr 70 in the Orion Belt region. The peculiar frequencydistribution of the radial velocities is discussed. Their conspicuoussystematical spatial distribution corresponds perfectly to the gradientof distance moduli found by Hardie et al. (1964). Therefore the presenceof two additional subgroupings in the Ori OB 1 association is proposed.Comparison with the radial velocities in the various subgroups of theOri OB 1 complex as defined by Blaauw (1964) does not yet reveal aconsistent kinematical picture.
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A photometric study of the Orion OB 1 association. III - Subgroup analyses
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1978ApJS...36..497W&db_key=AST
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A photometric study of the Orion OB 1 association. I - Observational data.
A catalog of observational data is presented for stars in the region ofthe young stellar association Orion OB 1. Photoelectric observationsobtained in the uvby-beta and UBV systems are compiled along withprevious photoelectric and spectroscopic data for all these stars aswell as for several bright members of the association with availablephotometric indices. Mean weighted values are computed for thephotometric data and summarized in tables expected to be reasonablycomplete for association members earlier than spectral type A0.Membership criteria are derived, and qualitative membershipprobabilities summarized, for the 526 stars in the final program. Theanalytical procedures are discussed for association stars of B,intermediate, and AF types. Effects of the nebular environment andvarious calibrations of Balmer-line and four-color indices areconsidered for the determination of absolute magnitudes for the B-typestars.
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Scanner K-line photometry of Orion stars
Results are presented for two-channel scanner measurements of calciumK-line strengths in 39 Orion sword and belt stars. Values of the calciumk index and its associated standard error are given for each observedstar, and the K-line strengths are compared with those of K-linestandard stars and Hyades stars. Plots of k index againstreddening-corrected color and of k-index deviation againstmetal-strength index deviation are provided which show that the Orionsword and belt stars do not differ significantly in their calcium andmetal abundances from general field stars.
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Spectral classification in the belt of ORI OB1.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1976AJ.....81..537G&db_key=AST
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Interstellar extinction in the Orion association
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1968ApJ...152..913L&db_key=AST
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