The star SMSS J200322.54-114203.3. in the centre, with crosshairs, in the south-eastern corner of th
The star SMSS J200322.54-114203.3. in the centre, with crosshairs, in the south-eastern corner of the constellation Aquila (the Eagle) close to the border with Capricornus and Sagittarius. Credit: Da Costa/SkyMapper

 

An international research team with Swedish involvement, lead by astronomers at Australian National University, has discovered an ancient star with a unique chemical composition. In particular, the high levels of zinc and uranium found in this object points to the existence of rapidly spinning and highly magnetized stars exploding only a billion years after the Big Bang in so called magneto-rotational hypernovae.

The other possible explanation for the unusual abundance patters of this old star is a merger of two neutron stars, however, the authors show that this theory provides a worse fit to the data. Only the violent collapse of a very early star – amplified by rapid rotation and the presence of a strong magnetic field – can account for the additional neutrons required to synthesize the chemical elements.

Dr. Karin Lind at the Department of Astronomy, Stockholm University, is co-author and part of the research group behind the discovery. She assisted the lead authors with the spectrum analysis, in particular with regards to non-equilibrium effects.

 

”Measuring elemental abundance from high-resolution stellar spectra is a complex science, but in cases such as these also extremely rewarding. This discovery sheds light on the origin of all chemical elements beyond the iron-peak, e.g. gold and silver”, she says. 

 

The research is published today in the journal Nature.

Press release: https://astro3d.org.au/new-type-of-massive-explosion-explains-mystery-star/

“Magnetorotational hypernovae are another astronomical r-process site”

DOI: 10.1038/s41586-021-03611-2