Bibcode
Balick, Bruce; Gomez, T.; Alcolea, J.; Vinkovic, D.; Corradi, R.; Frank, A.
Referencia bibliográfica
American Astronomical Society, AAS Meeting #217, #256.02; Bulletin of the American Astronomical Society, Vol. 43, 2011
Fecha de publicación:
1
2011
Número de citas
0
Número de citas referidas
0
Descripción
The history of mass loss and chemical enrichment is inscribed on the
nebulae surrounding post-AGB stars. Of these objects the most prominent
record is the circumnuclear region of the Egg Nebula. We present changes
in structure and surface brightness of CRL2688 derived from several
pairs of Hubble Space Telescope images taken between 1995.5 and 2009.6
in the F606W filter. We find that over the course of 6.7 y the N and S
lobes brightened by 15% and 30%, respectively, and both lobes grew
nearly uniformly from the illuminating star with a kinematic age of
266±25y. The ensemble of surrounding arcs brightened by 10-25%.
We are analyzing the data with the intent of determining whether the
growth pattern of the ensemble of quasi-circular arcs is constant proper
motion per arc [(dr/dt) = constant] or uniform [(dr/dt) ∝ r]. In
addition we present new four-color images of CRL2688 and use them to
model the geometric distribution and scattering properties of the dust.