X-ray line emission from Capella

Abstract

X-ray emission-line components from Mg, Si, S, and Fe are unambiguously detected from Capella with the solid-state spectrometer onboard the Einstein Observatory. The X-ray spectrum is inconsistent with an isothermal corona, and requires components between 6-million K and at least 24-million K for an adequate fit. An inhomogeneous corona in which the X-ray emitting plasma is confined to magnetically contained loops appears to be reconcilable with all of the experimental evidence.