Coronal emission from the shocked circumstellar ring of SN 1987A
Lundqvist, P.; Spyromilio, J.; Gröningsson, P.; Fransson, C.; Leibundgut, B.; Nymark, T.; Lundqvist, N.; Chevalier, R.
Sweden, United States, Germany
Abstract
High resolution spectra with UVES/VLT of SN 1987A from December 2000 until November 2005 show a number of high ionization lines from gas with velocities of ± 350 km s-1, emerging from the shocked gas formed by the ejecta-ring collision. These include coronal lines from [Fe X], [Fe XI] and [Fe XIV] which have increased by a factor of 20 during the observed period. The evolution of the lines is similar to that of the soft X-rays, indicating that they arise in the same component. The line ratios are consistent with those expected from radiative shocks with velocity 310{-}390 km s-1, corresponding to a shock temperature of (1.6{-}2.5)× 106 K. A fraction of the coronal emission may, however, originate in higher velocity adiabatic shocks.