Poster abstract details

Hubble Space Telescope images of CRL2688 (Egg Nebula) show a symmetric pair of bright lobes extending to a radius of $7^{\prime\prime}$ on both sides of a opaque dusty ellipsoid, all of which is surrounded by concentric circular arc segments extending to $\sim40^{\prime\prime}$. New Hubble images from 0.6 to 1.7 $\mu$m reveal significant variations color and opacity in the distribution of scattered starlight. We have constructed a detailed radiation-transfer model consisting principally of an optically thick equatorial disk-like structure; bipolar lobes with density enhancements along the polar axis and at the base of lobes; an optically thin extended envelope containing spherical density-enhanced shells to mimic the outer rings of CRL2688; and a pair of near-stellar caps that collimate and redden the dispersing starlight near its source. We used the code LELUYA (www.leluya.org) that calculates dust scattering, absorption and thermal emission on a highly unstructured triangular self-adaptive grid that simultaneously traces the density and optical depth and their gradients. Our model nicely reproduces all of the basic features detected in the four-color HST images, including the famous searchlights and arcs, as well as the measured spectral energy distribution (``SED'') of CRL2688. Assuming a distance of 420 pc we estimate the light originates in a giant star with a temperature T$_* \sim$ 7000 K and a luminosity as $5500 \pm 1100$ L$_{\odot}$.