Synthetic polarization and flux spectra are presented for aspherical, electron scattering-dominated photospheres of Type II supernovae (SN II) in general and the specific case of SN 1993J. Monte Carlo calculations are based on the following assumptions: a) ellipsoidal envelopes with power law density profiles; b) occupation numbers given by local thermodynamical equilibrium (LTE); c) pure electron scattering for continuum opacities; d) lines treated in a Sobolev approximation with an assumed constant thermalization fraction; e) line transitions result in depolarization; and f) the temperature structure is given by a gray extended atmosphere.The observed luminosity of a Type II supernova depends on the unknown inclination angle i. Spectral analysis alone will fail to detect even strong deviations from spherical symmetry. Line scattering depolarizes incident polarized light, but the residual intrinsic polarization does not completely vanish because of electron scattering effects that depend on the electron density distribution. By combining results on the polarization and velocity structure of the emission lines, and the degree of polarization in the continuum, we place strong constraints on the degree of asphericity, the inclination of the system and the electron density distribution. In addition, since the problem is over constrained, we can independently test for the contribution to the polarization caused by aligned interstellar grains between the SN and earth.These modelling techniques have been applied to SN1993J. Both the flux spectra and the percentage of polarization as a function of wavelength can be reproduced by an aspherical model with an axis ratio of 0.6, radial electron densities proportional to r −5 and an effective temperature of 4800 K. In an oblate model, SN 1993J is seen almost equator on. The line forming region is still within the hydrogen rich part of the envelope 3 weeks after the explosion, although the continuum may form in deeper layers. Although the residual polarization across Hα is not zero, the interstellar component derived herein is consistent with that deduced by Trammell et al. (1993). The power of this technique for investigating the structure of other SN II, as a method for independently deriving the interstellar polarization, and the implications of these results on the use of SN II to determine distances through the Baade-Wesselink method are discussed.-2 -

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We present narrow-band Hα, [S II], and [O I] Hubble Space Telescope images of the young planetary nebula GL 618. This object is a compact, bipolar nebula that is currently undergoing the transition from asymptotic giant branch star to planetary nebula. Our images confirm the presence of at least three highly collimated outflows emanating from the central regions of GL 618. We also detect Hα emission close to the central dust lane and in an extended scattered light halo. The three outflows are occurring simultaneously in this object, as opposed to being the result of a precessing jet. We derive an inclination for the brightest outflow in the East lobe of 39 • ± 4 • . This differs from the previous estimate of 45 • . In addition, our results indicate that the outflows seen in GL 618 are probably not coplanar. Line strengths derived from the narrow-band images indicate a shock velocity in the range of 40 − 100 km s −1 . Based on the shock velocity we estimate that the age of the outflows is less than 500 years. The outflows seen in the optical images of GL 618 are related to features seen in near-IR, CO and CS maps of this object. This relationship indicates that the outflows are playing a major role in the morphological evolution of this young planetary nebula, interacting with and shaping the neutral envelope surrounding GL 618. We discuss the implications of these jets and their interaction with the neutral envelope in the context of current models of planetary nebula formation.Subject headings: circumstellar matter-ISM: jets and outflows-planetary nebulae: general-planetary nebulae: individual(GL 618)

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