HST Emission Line Images of the SN1987A Environment
Session 66 -- Supernova Remnants
Oral presentation, Thursday, 2, 1994, 10:00-11:30

## [66.02] HST Emission Line Images of the SN1987A Environment

Christopher J. Burrows (STSci), J. Jeff Hester (Arizona State University), John Krist (STSci), Karl R. Stapelfeldt (JPL), John Trauger (JPL), and the WFPC-2 IDT

Images taken with the Wide Field Planetary Camera 2 at H$\alpha$ (F656N) and O III (F502N) of the environs of the remnant of SN1987A clearly show two outer loops of nebulosity in addition to the inner ring. These outer rings have been imaged from the ground, but never before seen with HST's resolution. The images show that the outer loops are two unresolved complete elliptical or circular rings, and apparently are not the limb brightened hourglass that had been previously supposed. An axisymmetric limb brightened thin emitting shell would have a brightness profile that falls inversely with the square root of the distance from the edge convolved with the instrumental profile. These images show essentially no emission within the ellipses. If the observed ellipses originate from luminous material located in planes parallel to the plane of the inner ring (inclined at 43$^{\circ}$ to the line of sight), then their deprojected shape would be almost circular. In contrast the inner ring does have resolved extended emission associated with it. A possible mechanism for this structure might be instabilities or density variations in the shock associated with the interaction of a blue supergiant wind with an inhomogeneous axisymmetric wind from a previous red supergiant phase of the progenitor. The remnant itself is resolved to a deconvolved FWHM of 0.14$^{\prime\prime}$