Abstract
Galactic Rotation.—Prof. P. Stroobant, Director of the Uccle Observatory, has been making a study of the radial velocities of the helium stars (types B0 to B7) in connexion with the problem of galactic rotation (Bull. of Acad. Roy. de Belgique, 1930, No. 10). His results indicate galactic longitude 141°, or 321° for the centre; the work of others leads to the selection of the second value. The centre is placed at a distance of 9250 parsecs from the sun; adopting 270 km./sec. as the sun's rotational speed, the period of rotation would be about 200 million years. The central mass required to control the motion is given as 16 × 1010 sun. The diameter of the galaxy is estimated as 23,000 parsecs. The Uccle Observatory is soon to have a new telescope with an aperture of a metre: also a new transit circle. Prof. Stroobant hopes to continue the research with the aid of these instruments.
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Astronomical Topics. Nature 128, 764 (1931). https://doi.org/10.1038/128764a0
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DOI: https://doi.org/10.1038/128764a0