High-resolution X-ray study of Eta Carinae reveals stellar wind dynamics

Star system: Eta Carinae A | Distance from the Sun: 7500 light years

Eta Carinae, a supermassive binary system, is undergoing extreme wind-driven mass loss, producing shock-heated X-ray emitting plasmas. Observations by the XRISM X-ray observatory in 2023 and 2024 captured unprecedentedly detailed spectra in the iron K band (6.2–7.1 keV).

Key findings

  
Three velocity components were identified in the hydrogen-like and helium-like iron lines, with maximum velocities of 2000–3000 km/s.
  
Iron fluorescent lines showed moderate blueshift and broadening, consistent with the primary wind's velocity field.
  
For the first time, a Compton shoulder of the helium line complex was observed.


The study highlights the dynamics of stellar winds and their interaction, providing insights into the extreme environment of Eta Carinae. These findings contribute to our understanding of massive stellar systems and their evolution.

Scientific study

High Spectral Resolution X-ray Observations of the Evolved Supermassive Stellar Binary System Carinae - Iron K Band Profile Revealed with XRISM (external link)