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Comment by irrational | Hacker News Reader

> Such collisions produce a kilonova – an explosion 1,000 times more powerful than a standard supernova. However, one very speculative theory is that if one of the neutron stars is highly magnetized – a magnetar – it could greatly amplify the power of the explosion even further to 100 times the brightness of a normal supernova.

Uh… maybe my reading comprehension is bad, but are “1,000” and “100” switched in this paragraph?

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Nope, you're not imagining things. The article actually quite wrong here: kilonovae are so named because they yield ~1000 times the peak luminosity of classical novae (~1e8 Lsun vs ~1e5 Lsun), not supernovae. For that matter, supernovae are themselves also named that way because their peak luminosities far exceed that of classical novae (with the most luminous recorded being >1e11 Lsun). I am not an expert on magnetar mergers in particular but according to the MNRAS paper that is cited, the transient in question, AT 2023fhn, gave a peak luminosity of about 4e8 Lsun (under certain assumptions about wavelength dependence, distance, etc) --- nowhere near supernova territory. Notably, the paper doesn't actually make the same claim about magnetars that the HN-posted article does.

I think brightness (being distributed over there surface area of a sphere) scales with the square root of energy released.

Different kinds of stellar explosions put different fractions of their output into visible light.

Yes, but it says "it could greatly amplify the power of the explosion even further". So... 100x is even further than 1000x? Or, is it 1000x and then a further 100x (or 100,000x?)

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