A different team of scientists discovered a vampiric neutron star casually shredding its neighbor. As stars do.

In this case, researchers were looking at a known binary star system, Swift J1858, that gives off blasts of X-ray light. Using a combination of the Hubble and XMM-Newton space telescopes, the Very Large Telescope, and the Spanish Gran Telescopio Canarias, they captured exceptionally good data of a recent eruption and were able to untangle some of the weird physics that goes into stars eating stars.

Lead author Noel Castro Segura explains: Eruptions like this are rare, and each of them is unique. Normally they are heavily obscured by interstellar dust, which makes observing them really difficult. Swift J1858 was special because even though it is located on the other side of our galaxy, the obscuration was small enough to allow for a full multiwavelength study.

And what they found is a messy eater. While the neutron star was pulling some material directly off its neighbor and onto its surface, the gravitational pulls and light pressure pushes of the system, mixed with a large dose of angular momentum, caused other material to get stripped off and flung into space at high speeds. According to a release on this work: …the team [was] able to study the temporal evolution of the gas that flows out. They found that the warm wind was not affected by the strong variations in the brightness of the system. The absence of such a response had previously been an unconfirmed theoretical prediction based on sophisticated simulations.

The science around this work is awesome, but what may be more amazing is the collaboration this research required. As collaborator Castro Segura explains: In this research we combined the unique capabilities of the HST with the best ground-based telescopes, such as the VLT and GTC, to obtain a complete picture of the dynamics of the gas in the system, from the near-infrared to ultraviolet wavelengths. This allowed us to unveil for the first time the true nature of these powerful outflows.

Altogether they coordinated ten different telescopes to see this one target of opportunity.

That phrase, “target of opportunity”, has a special meaning in astronomy. It refers to things that just happen when they happen that require researchers to stop whatever they are doing to switch over and look at that one special thing. Lead author Nathalie Degenaar stated: Designing such an ambitious observing campaign – built around the best telescopes on Earth and in space – was a huge challenge. So, it is incredibly exciting that all this work has paid off and allowed us to make a key discovery that would not have been possible otherwise.

The results of this work are published in Nature, and we expect this is just the first of many papers that will come from this amazing data set.

More Information

University of Southampton press release

“A persistent ultraviolet outflow from an accreting neutron star binary transient,” N. Castro Segura et al., 2022 March 2, Nature