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arXiv · 0909.0618

Kinematics of OB-associations and the new reduction of the Hipparcos data

A. M. Melnik·A. K. Dambis
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Abstract

The proper motions of OB-associations computed using the old (Hipparcos 1997} and new (van Leeuwen 2007) reductions of the Hipparcos data are in a good agreement with each other. The Galactic rotation curve derived from an analysis of line-of-sight velocities and proper motions of OB-associations is almost flat in the 3-kpc neighborhood of the Sun. The angular rotation velocity at the solar distance is Omega_0=31 +/-1 km s-1 kpc-1. The standard deviation of the velocities of OB-associations from the rotation curve is sigma=7.2 km s-1. The distance scale for OB associations (Blaha & Humphreys 1989) should be shortened by 10-20%. The residual velocities of OB-associations calculated for the new and old reductions differ, on average, by 3.5 km s-1. The mean residual velocities of OB-associations in the stellar-gas complexes depend only slightly on the data reduction employed.

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A. M. Melnik, A. K. Dambis. 2009-09-03. Kinematics of OB-associations and the new reduction of the Hipparcos data. https://doi.org/10.1111/j.1365-2966.2009.15484.x

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