Using the most powerful telescopes on the ground and in space, a team of astronomers has discovered for the first time gusts of hot, warm and cold winds blowing from a neutron star as it devours matter from a neighbouring star. The discovery offers insights into the behaviour of some of the most extreme objects in the universe.
Low-mass X-ray binaries (LMXBs) are systems containing a compact object: a neutron star or a black hole. They are powered by material stripped from a companion star, a process known as accretion. Most of the accretion occurs during violent flares, during which the systems' luminosity increases dramatically. At the same time, some of the material spiraling around the compact object is propelled into space in the form of winds and jets.
The most common signatures of matter escaping from astronomical objects are associated with "warm" gas. Despite this, only winds of "hot" or "cold" gas had been observed in variable X-ray binaries, until now. In this new study, a team of researchers from eleven countries studied the recent outburst of the X-ray binary known as Swift J1858. They used a combination of telescopes, including NASA's Hubble Space Telescope (HST), the European Space Agency's XMM-Newton satellite, the European Southern Observatory's Very Large Telescope (VLT), and Spain's Gran Telescopio Canarias (GTC).
The results, published in the journal Nature , showed persistent signatures of a warm wind in ultraviolet wavelengths occurring simultaneously with signatures of a cold wind in optical wavelengths. This is the first time that winds from such a system have been observed in different bands of the electromagnetic spectrum.