Mass loss from the progenitor of SN1006?”

ESTELA MARTA REYNOSO; GABRIELA CASTELLETTI; DAVID A. MOFFETT

Cariló, Argentina

Workshop; Massive stars: fundamental parameters and circumstellar Interactions; 2006

Type Ia supernovae (SN) are thought to arise from ignition of a white dwarf, so that their ambient medium is not expected to have been appreciably altered. However, mass loss from the companion may modify the environment in the vicinity of the progenitor binary system. We have observed the remnant of the prototypical type Ia SN 1006 with high resolution and sensitivity using the Very Large Array (VLA) and the Australia Telescope Compact Array. These data are combined with observations performed 11 years before with the VLA to measure the expansion of the radio shell. The expansion parameter m, defined as R proportional to tm, is found to be ~0.6 for the brightest lobes. We analyze this result in the light of theoretical models, according to which the value obtained for m appears to be compatible with an exponential or power-law ejecta density profile interacting with a circumstellar density profile decreasing as r-2, characteristic of steady presupernova mass loss.