Publications
of the
MPIfR
Optical & Infrared
Interferometry Group
Weis, K.
LBV (Candidate) Nebulae: Bipolarity and
Outflows
in: K.A. van der Hucht, A. Herrero & C.
Esteban (eds.),
A Massive Star Odyssey, from Main Sequence to Supernova,
Proc. IAU Symp. No. 212 (San Francisco: ASP),
p. 757
Abstract.
The most massive evolved stars (above 50 M_sun) undergo a
phase of extreme mass loss in which their evolution is reversed
from a redward to a blueward motion in the HRD. In this phase
the stars are known as Luminous Blue Variables (LBVs) and they
are located in the HRD close to the Humphreys-Davidson limit. It
is far from understood what causes the strong mass loss or what
triggers the so-called giant eruptions, active events in which
in a short time a large amount of mass is ejected. Here I will
present results from a larger project devoted to better understand
LBVs through studying the LBV nebulae. These nebulae are formed
as a consequence of the strong mass loss. The analysis concentrates
on the morphology and kinematics of these nebulae. Of special
concern was the frequently observed bipolar nature of the LBV
nebulae. Bipolarity seems to be a general feature and strongly
constrains models of the LBV phase and especially of the formation
of the nebulae. In addition we found outflows from LBV
nebulae, the first evidence for ongoing instabilities in the nebulae.