High-Velocity Lyα Emission from SNR 1987A
Abstract
The high-velocity Lyα emission from SN 1987A observed with the Space Telescope Imaging Spectrograph (STIS) evidently comes from a reverse shock formed where the outer envelope of SN 1987A strikes ionized gas inside the inner circumstellar ring. The observations can be explained by a simple kinematic model, in which the Lyα emission comes from hydrogen atoms with radial velocity ~15,000 km s-1 crossing a reverse shock in the shape of a slightly prolate ellipsoid with equatorial radius 4.8×1017 cm or ~80% of the distance to the inner surface of the inner ring. N V λλ1239, 1243 emission, if present, has a net luminosity <~30% times that of the Lyα emission. Future STIS observations should enable us to predict the time of impact with the inner ring and to determine unambiguously whether or not N V emission is present. These observations will offer a unique opportunity to probe the structure of SN 1987A's circumstellar environment and the hydrodynamics and kinetics of very fast shocks.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- January 1998
- DOI:
- 10.1086/311097
- Bibcode:
- 1998ApJ...492L.143M
- Keywords:
-
- STARS: CIRCUMSTELLAR MATTER;
- HYDRODYNAMICS;
- STARS: SUPERNOVAE: INDIVIDUAL ALPHANUMERIC: SN 1987A;
- ULTRAVIOLET: ISM;
- Stars: Circumstellar Matter;
- Hydrodynamics;
- Stars: Supernovae: Individual: Alphanumeric: SN 1987A;
- Ultraviolet: ISM