Photoelectric Photometry of Stars in the Orion Standard Region
Magnitudes and color indices in the Vilnius seven-color photometricsystem are given for 108 stars in the Orion standard region around theOrion Belt and the star lambda Orionis. New spectral and luminosityclasses, estimated from the photometric data, are given for some of thestars.
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The Orion complex according to observations of the space telescope Glazar.
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Stars of Early Types in the Region of Stellar Association OB1 Observed with the Glazar Telescope
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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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IUE observations of the broad continuum feature at 1400 A in the silicon and related stars
The upper main sequence chemically peculiar stars have previously beenstudied spectrophotometrically using low-resolution TD-1 spectra. Theseshow that the broad continuum feature at 1400 A is a useful indicator ofSi anomaly. In this paper the observations are extended to IUElow-resolution spectra and it is shown that this feature is indeed wellcorrelated with Si and also with optical chemical peculiarity indices.Its utility in selecting silicon stars is further demonstrated. Thisfeature is likely due to autoionization of Si II and is the bestavailable discriminator of the overabundance of a key element in the Apstars.
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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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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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Ultraviolet photometry from the Orbiting Astronomical Observatory. XX - The ultraviolet extinction bump
Ultraviolet extinction bumps are investigated in the interstellarextinction curves between 1800 and 3600 A for 36 stars which have (B-V)excesses ranging from 0.03 to 0.55 and are mostly confined to thebrighter OB associations distributed along the galactic plane. Eachextinction curve is found to have a broad bump which peaks near 2175 Aand whose position and profile appear to be constant among all thestars. It is shown that the bump is probably interstellar in origin andthat the constancy of its position and shape places such severerestrictions on grain geometrical parameters that classical scatteringtheory cannot be used to explain the feature unless the dust grains inwidely separated regions of space and with very different physicalconditions are assumed to have nearly identical size and shapedistributions. Three extinction curves which extend to 1100 A areexamined and found to have the same general characteristics as theothers. Several extinction curves are analyzed for fine structure, butno convincing evidence is found in the present interval. Some processesare discussed which may be responsible for the bumps.
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The Meridian Proper Motions of 161 Stars in the Region of the Belt of Orion.
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INHABITED SKY
