Abstract
view Abstract Citations (1) References Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The magnitudes, colors, and motions of stars of the spectral class R. Vandervort, Lee Gordon Abstract Visual magnitudes and colors of 98 stars of spectral class R have been observed with a photoelectric photometer and reduced to the system of Johnson and Morgan (1953). The average probable error of one magnitude amounted to +0.055 mag. and that of the color, +0.039 mag. The variation of the color with spectral class is shown in the following table. Subclass No. stars Av. color p.e. 1 Ro 19 1.22 +0.13 R2 28 1.33 0.13 23 1.57 0.16 R8 7 2.10 o.o8 Var. 21 2.46 0.46 Proper motions of 57 stars were obtained from various sources; those of the remaining 41 stars were derived from comparison of the positions given in the astrographic catalogues with those measured on plates taken with the 26-inch McCormick refractor. Radial velocities were found for 66 stars, mostly from the list of Sanford (1944) or Wilson (1953). Seven so-called CH stars were rejected in our discussion, since their velocities are extremely large and their distribution on the sky is limited to one side of the celestial sphere. The position of the solar apex and the solar velocity derived from the radial velocities were found to be R.A. = 2970, Dec. = +380, and V0 = 33.7 + 5.2 km/sec. Statistical parallaxes were derived by means of the parallactic motion as well as by the use of the r-components compared with the peculiar components of the radial velocities. After correcting the apparent magnitudes for the interstellar absorption, the average absolute magnitudes were derived for the two groups of stars as shown in the second table. Group No. stars M RoandR~ 43 +0.44+0.29 R5andR8 42 -1.10+0.49 Johnson, H. L. and Morgan, W. W. 1953, Ap. J. 117, 313. Sanford, R. R. 1944, Ap. J. 99, 145. Wilson, R. E. 1953, General Catalogue of Stellar Radial Velocities (Carnegie Inst. of Wash. Pub. 601), Washington, D. C. Leander McCormick Observatory, Charlottesville, Va. Publication: The Astronomical Journal Pub Date: September 1958 DOI: 10.1086/107763 Bibcode: 1958AJ.....63..311V full text sources ADS |
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