Observing Supernova 1987A with the Refurbished Hubble Space Telescope

Let Me See Your Supernova As the matter expelled from a supernova travels through and interacts with the interstellar medium, it creates a radiating structure called a supernova remnant. In 1987, astronomers detected a bright supernova in our galaxy, SN 1987A, the remains of which are now expanding into and interacting with a dense ring of gas and dust that surrounds the explosion site. France et al. (p. 1624, published online 2 September; see the Perspective by Laming) obtained spectroscopic data of the ring surrounding SN 1987A and compared it with similar data acquired in 2004. Because SN 1987A is so close to us, the explosion was visible to the naked eye and the results provide a glimpse into the hydro dynamics and kinetics of fast astrophysical shocks in a young supernova remnant. Images of the remnants of a stellar explosion reveal details of fast astrophysical shock waves. Observations with the Hubble Space Telescope (HST), conducted since 1990, now offer an unprecedented glimpse into fast astrophysical shocks in the young remnant of supernova 1987A. Comparing observations taken in 2010 with the use of the refurbished instruments on HST with data taken in 2004, just before the Space Telescope Imaging Spectrograph failed, we find that the Lyα and Hα lines from shock emission continue to brighten, whereas their maximum velocities continue to decrease. We observe broad, blueshifted Lyα, which we attribute to resonant scattering of photons emitted from hot spots on the equatorial ring. We also detect N v λλ1239, 1243 angstrom line emission, but only to the red of Lyα. The profiles of the N v lines differ markedly from that of Hα, suggesting that the N4+ ions are scattered and accelerated by turbulent electromagnetic fields that isotropize the ions in the collisionless shock.