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Expansion of W 3(OH)

Jonathan H. Kawamura·Colin R. Masson
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Abstract

A direct measurement of the expansion of W 3(OH) is made by comparing Very Large Array images taken about 10 yr apart. The expansion is anisotropic with a typical speed of 3 to 5 km/s, indicating a dynamical age of only 2300 yr. These observations are inconsistent with either the freely expanding shell model or a simple bow shock model. The most favored model is a slowly expanding shell-like HII region, with either a fast rarefied flow or another less massive diffuse ionized region moving towards the observer. There is also a rapidly evolving source near the projected center of emission, perhaps related to the central star.

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Jonathan H. Kawamura, Colin R. Masson. 1998-08-07. Expansion of W 3(OH). https://doi.org/10.1086/306472

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