Spectacular shock wave from a rejected star streaking through space at 100,000 miles per hour

Zeta Ophiuchi was once in close orbit with another star, before being ejected when that companion was destroyed in a supernova explosion. Infrared data from Spitzer reveals a dramatic shock wave that was formed by material blowing off the star’s surface and slamming into gas in its path. Chandra’s data shows an X-ray emission bubble located around the star, produced by gas that was heated by the shock wave to tens of millions of degrees. Chandra’s data helps shed more light on this runaway star’s story. Credit: X-Ray: NASA/CXC/Univ. of Cambridge/J. Sisk-Reynes et al. ; Radio: NSF/NRAO/VLA; Lens: PanSTARRS

  • Zeta Ophiuchi is a unique star that probably had a companion that was destroyed when it went supernova.
  • The supernova explosion sent Zeta Ophiuchi, seen in Spitzer (green and red) and Chandra (blue) data, hurtling into space.
  • The X-rays detected by Chandra come from a gas that has been heated to millions of degrees by the effects of a shock wave.
  • Scientists are working to match computer models of this object to explain the data obtained at different wavelengths.

Zeta Ophiuchi is a star with a complicated past, as it was likely ejected from its birthplace by a powerful stellar explosion. A new look detailed by[{” attribute=””>NASA’s Chandra X-ray Observatory helps tell more of the history of this runaway star.

Located approximately 440 light-years from Earth, Zeta Ophiuchi is a hot star that is about 20 times more massive than the Sun. Evidence that Zeta Ophiuchi was once in close orbit with another star, before being ejected at about 100,000 miles per hour when this companion was destroyed in a supernova explosion over a million years ago has been provided by previous observations.

In fact, previously released infrared data from NASA’s now-retired Spitzer Space Telescope, seen in this new composite image, reveals a spectacular shock wave (red and green) that was formed by matter blowing away from the star’s surface and slamming into gas in its path. A bubble of X-ray emission (blue) located around the star, produced by gas that has been heated by the effects of the shock wave to tens of millions of degrees, is revealed by data from Chandra.

A team of astronomers has constructed the first detailed computer models of the shock wave. They have begun testing whether the models can explain the data obtained at different wavelengths, including X-ray, infrared, optical, and radio observations. All three of the different computer models predict fainter X-ray emissions than observed. In addition, the bubble of X-ray emission is brightest near the star, whereas two of the three computer models predict the X-ray emission should be brighter near the shock wave. The team of astronomers was led by Samuel Green from the Dublin Institute for Advanced Studies in Ireland.

In the future, these scientists plan to test more complex models with additional physics – including the effects of turbulence and particle acceleration – to see if the agreement with the X-ray data will improve.

A paper describing these results has been accepted into the journal Astronomy and astrophysics. The Chandra data used here was originally analyzed by Jesús Toala of the Institute of Astrophysics of Andalusia in Spain, who also wrote the proposal that led to the observations.

Reference: “Thermal emission from bow shocks. II. 3D magnetohydrodynamic models of zeta Ophiuchi” by S. Green, J. Mackey, P. Kavanagh, TJ Haworth, M. Moutzouri and VV Gvaramadze, accepted, Astronomy and astrophysics.
DOI: 10.1051/0004-6361/202243531

NASA’s Marshall Space Flight Center manages the Chandra program. The Smithsonian Astrophysical Observatory’s Chandra X-ray Center controls science operations from Cambridge, Massachusetts, and flight operations from Burlington, Massachusetts.

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