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LabRat [soylentnews.org] writes:

For the first time, astronomers have captured solid evidence of a rare double cosmic cannibalism — a star swallowing a compact object such as a black hole or neutron star. In turn, that object gobbled the star’s core, causing it to explode and leave behind only a black hole.

[...] Piecing the data together, Dong and his colleagues think this is what happened: Long ago, a binary pair of stars were born orbiting each other; one died in a spectacular supernova and became either a neutron star or a black hole. As gravity brought the two objects closer together, the dead star actually entered the outer layers of its larger stellar sibling.

The compact object spiraled inside the still-living star for hundreds of years, eventually making its way down to and then eating its partner’s core. During this time, the larger star shed huge amounts of gas and dust, forming a shell of material around the duo.

In the living star’s center, gravitational forces and complex magnetic interactions from the dead star’s munching launched enormous jets of energy — picked up as an X-ray flash in 2014 — as well as causing the larger star to explode. Debris from the detonation smashed with colossal speed into the surrounding shell of material, generating the optical and radio light.

While theorists have previously envisioned such a scenario, dubbed a merger-triggered core collapse supernova, this appears to represent the first direct observation of this phenomenon, Dong says.

Journal Referencess:
1) D. Dong et al. A transient radio source consistent with a merger-triggered core collapse supernova. [sciencemag.org] Science. Vol. 373, September 3, 2021, p. 1125. doi: https://doi.org/10.1126/science.abg6037 [doi.org]
2) N. Ivanova et al. Common envelope evolution: where we stand and how we can move forward. [springer.com] The Astronomy and Astrophysics Review. Vol 21, November 2013. doi: https://doi.org/10.1007/s00159-013-0059-2 [doi.org]

Original Submission