beecee Posted August 24, 2017 Posted August 24, 2017 https://phys.org/news/2017-08-theory-heavy-elements-primordial-black.html New theory suggests heavy elements created when primordial black holes eat neutron stars from within (Phys.org)—A team of researchers at the University of California has come up with a new theory to explain how heavy elements such as metals came to exist. The group explains their theory in a paper published in the journal Physical Review Letters—it involves the idea of primordial black holes (PBHs) infesting the centers of neutron stars and eating them from the inside out.https://phys.org/news/2017-08-theory-heavy-elements-primordial-black.html :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: The paper: https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.119.061101 Primordial Black Holes and r-Process Nucleosynthesis ABSTRACT We show that some or all of the inventory of r-process nucleosynthesis can be produced in interactions of primordial black holes (PBHs) with neutron stars (NSs) if PBHs with masses 10−14 M⊙<MPBH<10−8 M⊙ make up a few percent or more of dark matter. A PBH captured by a NS sinks to the center of the NS and consumes it from the inside. When this occurs in a rotating millisecond-period NS, the resulting spin-up ejects ∼0.1 M⊙–0.5 M⊙ of relatively cold neutron-rich material. This ejection process and the accompanying decompression and decay of nuclear matter can produce electromagnetic transients, such as a kilonova-type afterglow and fast radio bursts. These transients are not accompanied by significant gravitational radiation or neutrinos, allowing such events to be differentiated from compact object mergers occurring within the distance sensitivity limits of gravitational-wave observatories. The PBH-NS destruction scenario is consistent with pulsar and NS statistics, the dark-matter content, and spatial distributions in the Galaxy and ultrafaint dwarfs, as well as with the r-process content and evolution histories in these sites. Ejected matter is heated by beta decay, which leads to emission of positrons in an amount consistent with the observed 511-keV line from the Galactic center.
beecee Posted August 25, 2017 Author Posted August 25, 2017 Apologies first up: It seems I posted reference to this a couple of weeks ago at http://www.scienceforums.net/topic/108564-r-process-nucleosynthesis/#comment-1005697 Off goes my head, on goes a pumpkin! Perhaps a mod might like to merge? or delete one or the other?
Recommended Posts