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trinitree88
2017-Jul-02, 02:59 PM
The authors discuss all the key parameters in the formation of double neutron star systems. 62 pages, a long read....and possibly a short gamma ray burst upon endlife merger of the two. SEE:https://arxiv.org/abs/1706.09438

George
2017-Jul-03, 02:22 PM
Interesting how so much can come in short of a time. It seems that there's a "lot of gold in them thar Hill's Spheres". Correct me if I am reading it wrong, from pg. 37 (10.2), but it seems a NS will shred (Roche limit) just prior to merger creating an extremely brief jet from a remnant accretion disk. The DNS merger allows the r-process to be a "vital source" of chemical enrichment for heavy elements (e.g. gold) for the ISM. The mass ratios and eccentricities affect this production.

It also seems that a remnant disk (torus) around a BH will produce a heck of jet after merger, though lasting < 1 sec. or so, thus consistent with the sGRBs event times.

The mainstream view that BH-BH mergers (not addressed in this paper) don't produce GRBs is still beyond me a bit, though I assume no remnant BH disks are expected. [If there are cases where they do exist, then I would win my ice cream Sundae, (had anyone taken the bet, of course :)).

trinitree88
2017-Jul-03, 05:39 PM
Interesting how so much can come in short of a time. It seems that there's a "lot of gold in them thar Hill's Spheres". Correct me if I am reading it wrong, from pg. 37 (10.2), but it seems a NS will shred (Roche limit) just prior to merger creating an extremely brief jet from a remnant accretion disk. The DNS merger allows the r-process to be a "vital source" of chemical enrichment for heavy elements (e.g. gold) for the ISM. The mass ratios and eccentricities affect this production.

It also seems that a remnant disk (torus) around a BH will produce a heck of jet after merger, though lasting < 1 sec. or so, thus consistent with the sGRBs event times.

The mainstream view that BH-BH mergers (not addressed in this paper) don't produce GRBs is still beyond me a bit, though I assume no remnant BH disks are expected. [If there are cases where they do exist, then I would win my ice cream Sundae, (had anyone taken the bet, of course :)).
George. Yep, there's gold in them thar hills, in page 37. The idea that the r-process in supernovae created the gold is weakened a bit, and that a double NS merger does the trick has been confirmed. Earlier this past fall, I took a pair of students to hear Anna Frebel talk @ MIT with a nice piece of work on the predicted abundances of the heavy isotopes produced, followed by observations of several stars in a cluster in a faint dwarf galaxy, that one by one showed just those anomalous abundances in their spectra....confirming a nearby NS/NS merger. The tale of how she was woken up @ 3 AM in the morning, to an excited grad student confirming that not one, but all of the stars in the cluster showed the abundances, and that not one spectrum, but all of the spectra overlay the computer simulated spectra.....was pretty damn impressive, and opens up a whole new area of research. Sometimes, years of intense work pays off.
:scope: :clap: :dance:

George
2017-Jul-04, 12:57 AM
:clap::cool:

I wonder what percent of gold comes from binary stars that aren't and merge only to find themselves hiding inside space time?