The Early X‐Ray Emission from V382 Velorum (Nova Velorum 1999): An Internal Shock Model

We present the results of ASCA and RXTE observations of the early X-ray emission from the classical nova V382 Velorum. Its ASCA spectrum was hard ( kT ~ 10 keV) with strong (10 23 cm -2 ) intrinsic absorption. In the subsequent RXTE data, the spectra became softer, because of both a declining temperature and a diminishing column. We argue that this places the X-ray emission interior to the outermost ejecta produced by V382 Vel in 1999, and therefore it must have been the result of a shock internal to the nova ejecta. The weakness of the Fe Kα lines probably indicates that the X-ray-emitting plasmas are not in ionization equilibrium.