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Simultaneous Polarimetry and Photometry of the Young Stellar Object R Monocerotis
Linear polarization and flux of the young stellar object R Mon wereobserved simultaneously at seven bands in the optical wavelength from0.36 to 0.76 μm in 1991-1997. During the observational period, the Vmagnitude of R Mon changed by about 0.7 mag in a diaphragm of 18". Wehave found a strong positive correlation between the degree of linearpolarization p and the V magnitude and have found that the coefficientof correlation is 0.92 for the data in 1993-1997. The values of p and Vin 1991-1992 did not follow this correlation. The colors B-V, V-R_C,V-R_J, and R_C-I_C are also found to increase with the V magnitudeduring the whole observational period. However, in 1991 when the objectwas in the faintest phase, only the color U-B decreased. Thesecorrelations are similar to those observed in other Herbig Ae/Be stars.The position angle theta of the linear polarization also showssignificant variation with time, though the correlation between thetaand other quantities is weak. The observed correlations betweenmagnitude, colors, and polarization degree can be explained by thecombination of extinction by the clouds orbiting around R Mon andscattering by diffusely surrounding medium, as originally proposed byGrinin for Herbig Ae/Be stars. Since the timescale of variation is short(~10 days), the orbiting clouds should be in the vicinity, that is,<~10 AU, of the star. The extinction by those clouds less depends onwavelength than that observed in the diffuse interstellar medium. Thesize of grains in the clouds may be larger than those in the diffuseinterstellar clouds. Our Mie calculations show that the radius of grainsmay be in the range from 0.08 to 0.50 mum. Alternatively, if the cloudsare dense and opaque, ``gray'' extinction may occur and explain theobservation.
| Observations in regions of Cassiopeia, Gemini, and Monoceros with the Glazar space telescope
Observations at 1640 A of regions in Cassiopeia, Gemini, and Monocerosmade with the Glazar space telescope are presented; 7, 11, 13, and 35early-type stars brighter than about 9 mag were detected in the observedregions. The distribution of dust matter in the corresponding regions isstudied. It is determined that companions of HD 4442, 4797, and BD + 62deg 2225 are subdwarfs of sdB - sdO types; the hot companion of HD220102 may be of the type from B8 Ib-II to sdB. It is shown that HD 5233and 261490 are probably embedded in dense circumstellar envelopes.
| Catalog of BV magnitudes and spectral classes of 6000 stars
The present catalog, compiled at the Abastumani Observatory, contains BVmagnitudes and spectral classes of about 6000 stars up to V(lim) = 13.0min five circular areas of 18 sq deg located near the salactic-equatorplane. The catalog is intended for star-statistics studies ofstar-formation regions.
| The distribution of stars and obscuring matter in a Monoceros field
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1972A&AS....7...35K&db_key=AST
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