Talk:Kilonova

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"merge in a binary system"?[edit]

The first sentence says, "... when [two objects] merge in a binary system." Odd wording. Sounds a bit like they merge into a binary system. Is it intended to mean, "... when [two objects] in a binary system merge into each other"? Nurg (talk) 00:19, 17 October 2017 (UTC)[reply]

Origin of the term[edit]

I think that it would be useful to give a brief history (and etymology) of the word "kilonova" as this was unfamiliar to me before October 16, 2017. Is this a new word? Is a kilonova another word for a "short-duration GRB" (a term that has existed for decades) or is it slightly different? OtterAM (talk) 11:41, 17 October 2017 (UTC)[reply]

I came here to say this. I have found the origin and included it in the article. Nodekeeper (talk) 19:42, 18 October 2017 (UTC)[reply]

Short-duration GRBs[edit]

Should the article put more emphasis on the history of observation of short-duration GRBs? For example, optical counterparts to this class of GRBs were studied as early as 2005, and it was pretty well accepted that their most likely explanation was a collision of two neutron stars. The September 2017 event confirmed this model, of course. OtterAM (talk) 11:44, 17 October 2017 (UTC)[reply]

What's the result of such a merge?[edit]

If a black hole's involved in the merge, the neutron star will likely be absorbed by the black hole. If two neutron stars merge, will they always produce a black hole? Or can they produce a "new" neutron star of their combined masses? Ximalas (talk) 18:49, 25 October 2017 (UTC)[reply]

It's possibly a pure speculation, but a black hole of sufficiently small mass can make its way into a neutron star, devouring it from inside out. Ximalas (talk) 18:54, 25 October 2017 (UTC)[reply]

Whether a neutron star merger always produces a black hole depends on the Tolman-Oppenheimer-Volkoff limit (the mass limit for neutron stars above which they collapse into black holes). Neutron stars always have masses at or above the Chandrasekhar limit (the mass limit for electron-degenerate matter, beyond which it collapses into a neutron star) which is around 1.4 solar masses, so the merger of two neutron stars should produce a body of, at minimum, something like 2.6-2.7 solar masses (some material is thrown off in jets, and accretion at those densities is so energetic that the mass loss is significant). If that's more than the Tolman-Oppenheimer-Volkoff limit, it would follow that any neutron star merger product would be too heavy and immediately collapse into a black hole - but current estimates of that limit are not very precise (the value I've seen is "somewhere between 2 and 3 solar masses"), so we don't actually know whether it is or not. So: it might or might not be possible for two neutron stars that are both at the light end of the mass range, but if there's a medium-to-heavy one involved it's definitely going to be a black hole. Magic9mushroom (talk) 05:13, 29 October 2017 (UTC)[reply]

Actually neutron stars can have a mass less than the Chandrasekhar limit. The simplest evidence of this is a graph of neutron stars masses and black hole masses. https://media.ligo.northwestern.edu/gallery/mass-plot. It shows neutron stars with a mass less than 1 solar mass. As far as GW170817 goes, it is not known if the result is a neutron star or a black hole. The total mass of the system was between 2.73 and 3.29 Solar Masses with the individual masses being between 0.86 to 2.26 Solar Masses ^[1]. That puts the combined mass right in the mass gap between neutron stars and black holes. It is also not known how much mass was ejected. Some of this I think you said, but it was easiest just to repeat it. James65.pike (talk) 01:01, 26 December 2017 (UTC)[reply]

References

^ Abbot, B. P. (2017). "GW170817: Observation of Gravitational Waves from a Binary Neutron Star Inspiral" (PDF). Physical Review Letters. PRL 119 (161101).

Can we compare with novae and supernovae ?[edit]

Nova says "peak absolute magnitude is bimodal, with a main peak at magnitude −8.8, and a lesser one at −7.5.", supernova has table suggesting peak absolute magnitudes between -14 and -22 (averages by subtype). What range and distribution of absolute magnitudes do kilonovae have, or do they not have a visual magnitude ? - Rod57 (talk) 15:18, 30 October 2017 (UTC)[reply]

Absolute magnitude?[edit]

Searching for the absolute magnitude of such an event turns up very little. We don't have peak absolute magnitude numbers here or on GW170817. Would love to get this number. Zelmerszoetrop (talk) 17:44, 12 April 2019 (UTC)[reply]

The article should talk more about what goes during in a kilonova[edit]

There is no mention of it beyond "r-process". While the link used explains a lot, there's stuff relevant to kilonovas specifically. Key in there would be what's left behind. Is there a remnant? Or just debris? Will (Talk - contribs) 03:22, 20 November 2023 (UTC)[reply]

Just checked on if other articles mention what's left. Type Ia supernova includes:

The Type Ia supernova leaves no compact remnant, but the whole mass of the former white dwarf dissipates though space.

Will (Talk - contribs) 03:32, 20 November 2023 (UTC)[reply]

[BPAbbott2017-1] Abbot, B. P. (2017). "GW170817: Observation of Gravitational Waves from a Binary Neutron Star Inspiral" (PDF). Physical Review Letters. PRL 119 (161101).

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