Explosions of Thorne–Żytkow objects

• Published in: Monthly notices of the Royal Astronomical Society. Letters Vol. 475; no. 1; pp. L49 - L51
• Main Author: Moriya, Takashi J
• Format: Journal Article
• Language: English
• Published: Oxford University Press 01-03-2018
• Subjects: supergiants; accretion, accretion discs; supernovae: general; stars: neutron; stars: peculiar
• ISSN: 1745-3925; 1745-3933
• DOI: 10.1093/mnrasl/sly005

Abstract
We propose that massive Thorne–Żytkow objects can explode. A Thorne–Żytkow object is a theoretically predicted star that has a neutron core. When nuclear reactions supporting a massive Thorne–Żytkow object terminate, a strong accretion occurs towards the central neutron core. The accretion rate is large enough to sustain a super-Eddington accretion towards the neutron core. The neutron core may collapse to a black hole after a while. A strong large-scale outflow or a jet can be launched from the super-Eddington accretion disc and the collapsing Thorne–Żytkow object can be turned into an explosion. The ejecta have about 10 M⊙ but the explosion energy depends on when the accretion is suppressed. We presume that the explosion energy could be as low as ∼1047 erg and such a low-energy explosion could be observed like a failed supernova. The maximum possible explosion energy is ∼1052 erg and such a high-energy explosion could be observed as an energetic Type II supernova or a superluminous supernova. Explosions of Thorne–Żytkow objects may provide a new path to spread lithium and other heavy elements produced through the irp process such as molybdenum in the Universe.