The Evolving Structure of CRL2688: 14 Years of HST Images

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 autores
6
Número de autores del IAC
1
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.