Logo image
A Deep Exposure in High Resolution X-Rays Reveals the Hottest Plasma in the zeta Puppis Wind
Journal article   Open access   Peer reviewed

A Deep Exposure in High Resolution X-Rays Reveals the Hottest Plasma in the zeta Puppis Wind

David P. Huenemoerder, Richard Ignace, Nathan A. Miller, Kenneth G. Gayley, Wolf-Rainer Hamann, Jennifer Lauer, Anthony F. J. Moffat, Yael Naze, Joy S. Nichols, Lidia Oskinova, …
The Astrophysical journal, Vol.893(1), p.52
04/01/2020
DOI: 10.3847/1538-4357/ab8005
url
https://doi.org/10.3847/1538-4357/ab8005View
Published (Version of record) Open Access

Abstract

We have obtained a very deep exposure (813 ks) of zeta Puppis (O4 supergiant) with the Chandra HETG Spectrometer. Here we report on analysis of the 1-9 A region, especially well suited for Chandra, which has a significant contribution from continuum emission between well separated emission lines from high-ionization species. These data allow us to study the hottest plasma present through the continuum shape and emission line strengths. Assuming a power-law emission measure distribution that has a high-temperature cutoff, we find that the emission is consistent with a thermal spectrum having a maximum temperature of 12 MK as determined from the corresponding spectral cutoff. This implies an effective wind shock velocity of 900 km s(-1), well below the wind terminal speed of 2250 km s(-1). For X-ray emission that forms close to the star, the speed and X-ray flux are larger than can be easily reconciled with strictly self-excited line-deshadowing-instability models, suggesting a need for a fraction of the wind to be accelerated extremely rapidly right from the base. This is not so much a dynamical instability as a nonlinear response to changing boundary conditions.
Astronomy & Astrophysics Physical Sciences Science & Technology

Details

Logo image