Spectropolarimetric evidence of asymmetric outburst in the fast nova V1494Aquilae

We present our extended polarimetric observations of a fast nova from the p remaximum to transition stages. The observations were made for V1494 Aquila e (=Nova Aq1 1999 No. 2) at the Dodaira Observatory of the National Astrono mical Observatory of Japan between 1999 December 2 and 2000 March 29. We di scovered that the light from the nova had already been intrinsically polari zed in the premaximum stage and that the intrinsic polarization took a loca l maximum at visual maximum light. For the next 6 days a nearly orthogonal polarization component gradually increased. This component was later accomp anied and finally replaced by rapidly oscillating components. These observa tions provide direct evidence that an asymmetric geometry was present even prior to maximum brightness. The principal geometry of the wind projected o nto the sky appears nearly constant, at least from shortly after visual max imum to transition stages, but clumping of the ejecta appears to become sig nificant in the later stages.