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Astron. Astrophys. 357, 938-944 (2000)


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A kinematic and morphological investigation of the asymmetric nebula around the LBV candidate WRA 751

K. Weis *

Institut für Theoretische Astrophysik, Tiergartenstrasse 15, 69121 Heidelberg, Germany Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, 53121 Bonn, Germany

Received 18 August 1999 / Accepted 3 April 2000

Abstract

WRA 751 is an evolved massive star in our Galaxy closely resembling Luminous Blue Variable stars (LBVs). It is surrounded by a nitrogen enriched nebula of about 23" diameter. A comparative study of the nebula's morphology and kinematics is presented, it supports-together with spectroscopical evidence-the classification of WRA 751 as a LBV. Images show that the nebula consists of a nearly spherical shell as well as a bipolar-like structure north and south of its main body, the Northern and Southern Caps.

In contrast to the almost spherical appearance of the main body of the nebula, the kinematics shows a deviation even of this part from a classical spherical expansion pattern. From the present data it can be concluded that the main body expands asymmetrically (central expansion velocity [FORMULA] km s-1 ), with a thicker shell at the back side. A bump-like structure can be found to the west of the central star. In addition to the main body, bipolar kinematic components can be identified with the morphologically classified Caps. These results put WRA 751 into the class of LBVs which are surrounded by a nebula with bipolar components, albeit considerably less pronounced than, for instance, in the classical bipolar LBVs [FORMULA] Car and HR Car.

Key words: stars: individual: WRA 751 – stars: evolution – stars: mass-loss – ISM: bubbles – ISM: jets and outflows

* Visiting Astronomer, Cerro Tololo Inter-American Observatory, National Optical Astronomy Observatories, operated by the Association of Universities for Research in Astronomy, Inc., under contract with the National Science Foundation.

Send offprint requests to: K. Weis, Institut für Theoretische Astrophysik, Tiergartenstr. 15, D-69121 Heidelberg, Germany (kweis@ita.uni-heidelberg.de)

Correspondence to: K. Weis, Institut für Theoretische Astrophysik, Tiergartenstr. 15, D-69121 Heidelberg, Germany

© European Southern Observatory (ESO) 2000

Online publication: June 5, 2000

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