A strange kind of ‘hybrid’ star has been discovered almost 40 years since it was first hypothesized, but until now has been inquisitively hard to find. In 1975, famous astrophysicists Kip Thorne, of the California Institute of Technology (Caltech) in Pasadena, Calif., and Anna Żytkow, of the University of Cambridge, UK, gathered a theory on how a huge dying star could swallow its neutron star dual partner, thus converting into a very uncommon form of stellar hybrid, named a Thorne-Żytkow object (or TŻO). The neutron star, a solid husk of degenerate matter that was once was a huge star long since gone supernova, would convert into the red supergiant’s core, disturbing normal fusion procedures.
Image Credit: NASA/CORBIS, EDIT BY IAN O'NEILL
According to the Thorne-Żytkow theory, after the two entities have fused, a leftover of the elements rubidium, lithium and molybdenum will be produced by the hybrid star. So astrophysicists have been on the hunt for stars in our galaxy, which is supposed to contain only a few dozen of these things at any one time, with this precise chemical mark in their atmospheres.
Currently, according to Emily Levesque of the University of Colorado Boulder and her group, a bona fide TŻO has been detected and their results have been accepted for journal in the Monthly Notices of the Royal Astronomical Society Letters. Levesque said “Studying these objects is exciting because it represents a completely new model of how stellar interiors can work. In these interiors we also have a new way of producing heavy elements in our universe. You’ve heard that everything is made of ‘star stuff’—inside these stars we might now have a new way to make some of it.”
There are certain indirect variances between the observational results and theory, but, as Levesque’s group points out, stellar theory has progressed in the decades since Thorne and Żytkow’s original known work. Co-investigator Philip Massey, of Lowell Observatory in Flagstaff, Ariz said “We could, of course, be wrong. There are some minor inconsistencies between some of the details of what we found and what theory predicts. But the theoretical predictions are quite old, and there have been a lot of improvements in the theory since then. Hopefully our discovery will spur additional work on the theoretical side now.”
Publication: Discovery of a Thorne-Zytkow object candidate in the Small Magellanic Cloud, arXiv:1406.0001 [astro-ph.SR]
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