Key facts
- Researchers found that four stars once thought to require hypernovae can be accounted for by typical supernovae when asymmetrical ejection of elements is considered.
- The work was led by Anmol Aggarwal, a PhD candidate at the Mullard Space Science Laboratory of University College London, together with Dr. Ralph Schoenrich.
- Instead of observing new explosions, the team matched observed stellar chemistries with computer simulations of supernova yields.
- This halo star moves retrograde through the Galaxy at roughly 229 mi s⁻¹ (≈368 km s⁻¹) and likely formed in a dwarf system where neutron‑star collisions could have occurred before its incorporation into the Milky Way.
In recent March and August studies, researchers led by Anmol Aggarwal at the Mullard Space Science Laboratory of University College London and Ralph Schoenrich challenged hypernova evidence by matching stellar chemistries with supernova simulations, according to Earth.com reporting.
Earth.com reported that the work was led by Anmol Aggarwal, a PhD candidate at the Mullard Space Science Laboratory of University College London, together with Dr. Ralph Schoenrich. Researchers found that four stars once thought to require hypernovae, which are thought to be extremely energetic stellar explosions, can be accounted for by typical supernovae, which are stellar explosions, when asymmetrical ejection of elements (meaning the explosion’s debris is not evenly distributed) is considered. Rather than observing new explosions, the team compared observed stellar chemistries to computer simulations of supernova yields.
Earth.com reported that in their March study, three stars — one in the Sculptor dwarf galaxy, one with an iron abundance less than 0.00001 times solar, and one linked to an ~80‑solar‑mass progenitor — were reproduced more closely by ordinary supernova models than by hypernova models. For the 80‑solar‑mass case the mismatch score fell from about 19 to about 5.
Earth.com reported that the August study examined a fourth star, a uranium‑ and thorium‑rich red giant in the Milky Way halo, and showed that a combination of an ordinary supernova and a neutron‑star merger (a collision of two neutron stars) fits its chemistry better than a hypernova scenario. This halo star moves retrograde (moving opposite to the Galaxy’s rotation) through the Galaxy at roughly 229 mi s⁻¹ (≈368 km s⁻¹) and likely formed in a dwarf system where neutron‑star collisions could have occurred before its incorporation into the Milky Way.
Earth.com reported that observations of supernova remnants such as Cassiopeia A and SN 1987A reveal clumped, filamentary ejecta, and neutron‑star kicks show that the blasts are intrinsically uneven. The authors argue that galactic chemical‑evolution codes and interstellar‑medium models should incorporate incomplete mixing of supernova debris rather than assuming uniform distribution.
Earth.com reported that they propose that future high‑precision spectroscopic surveys of Sun‑like stars could detect the subtle level variations expected from patchy supernova enrichment (uneven distribution of elements from supernovae), providing an observational test. Both research papers appeared in the journal Monthly Notices of the Royal Astronomical Society.
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