But no matter how they form, astronomers in 2014 announced they may have discovered the first Thorne-Żytkow object. The star was hiding some 200,000 light-years away in the Small Magellanic Cloud, a dwarf galaxy that orbits the Milky Way.
It was found by astronomer Emily Levesque, now at the University of Washington, with the help of her team of researchers. To find the suspected TZO, Levesque’s group used New Mexico’s Apache Point Observatory to study two dozen red supergiant stars in the Milky Way, as well as one of the Magellan Telescopes in Chile to study another group of supergiants in the Small Magellanic Cloud.
Upon reviewing the data, one star in particular stood out. The system, dubbed HV 2112, was initially cataloged as variable in 1908 by pioneering astronomer Henrietta Swan Leavitt. At the time, though, astronomers thought it was a red supergiant living out its dying days before going supernova.
However, more than 100 years after Leavitt first noted the strange object, Levesque and her team’s analysis revealed unusual chemical signatures that they thought could be the tell-tale signs of a mythical Thorne-Żytkow object. The researchers saw excess amounts of lithium, calcium, and other elements, which they could only explain through the unique nuclear reactions that would occur inside a TZO.
But they couldn’t be completely sure; HV 2112 also seemed to have other strange chemical fingerprints that they didn’t expect to see. Based on these remaining mysteries, the team suggests that either theoretical models haven’t fully appreciated the nuances of Thorne-Żytkow objects, or HV 2112 simply wasn’t a TZO in the first place.
HV 2112: A strange star disputed