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

WRA 751 is an evolved massive star in our Galaxy closely resembling Luminou s Blue Variable stars (LBVs). It is surrounded by a nitrogen enriched nebul a of about 23 " diameter. A comparative study of the nebula's morphology an d kinematics is presented, it supports-together with spectroscopical eviden ce-the classification of WRA 751 as a LBV. Images show that the nebula cons ists 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 nebu la, the kinematics shows a deviation even of this part from a classical sph erical expansion pattern. From the present data it can be concluded that th e main body expands asymmetrically (central expansion velocity similar to 2 6 km s(-1)), with a thicker shell at the back side. A bump-like structure c an be found to the west of the central star. In addition to the main body, bipolar kinematic components can be identified with the morphologically cla ssified Caps. These results put WRA 751 into the class of LBVs which are su rrounded by a nebula with bipolar components, albeit considerably less pron ounced than, for instance, in the classical bipolar LBVs eta Car and HR Car .