
Scientists discover brightest supernova ever seen - uncertainquark
https://www.cfa.harvard.edu/news/2020-06
======
dak1
Anton Petrov has pretty decent coverage of this on his YouTube channel[1].

This type of supernova has been theorized, although to my knowledge not
previously observed (due to the mechanics, about 50% of the energy is radiated
as visible light, which is why they're so exceptionally bright).

We do have a star near us that is theorized to have undergone a pulsational
pair instability supernova in the 19th century: Eta Carinae.

[1]
[https://www.youtube.com/watch?v=dhjHs2L4kqw](https://www.youtube.com/watch?v=dhjHs2L4kqw)

~~~
nwallin
Eta Carinae underwent supernova _imposter_ events, not supernova. Otherwise
there wouldn't be an Eta Carinae.

------
coldcode
I wonder what this would look like from less than Galactic distances, i.e.
close enough to see but not close enough to incinerate.

~~~
Ididntdothis
There are historical reports about supernovae where they were visible during
the day for a few weeks. I guess it would look just like another bright star.
Makes me wonder what the minimum safe distance is.

~~~
duxup
Yean I was thinking the same thing.

How spectacular of a view could you get from an earth like planet ... and
still not have any ill effects?

Could it be a huge spectacular thing reaching across the entire sky, or would
by that stage you be in real trouble?

~~~
svachalek
Interesting question. My off-the-top instinct would be to say any explosion
that looks bigger than the sun is probably delivering more radiation than the
sun and that would be bad news. But that’s without doing any math.

(Also brings to mind the book Dhalgren.)

~~~
danparsonson
Somewhat :-) Supernovae are relatively easy to spot because they usually
outshine their entire host _galaxy_.

------
JoeAltmaier
With a total energy output of 10^44 Joules, it seems odd to exclaim over "500
times brighter!" I guess supernovae all exist in a very narrow band of
energies?

~~~
ben_w
One particular class of supernova is used as a standard candle for determining
the distances to other galaxies.

~~~
SiempreViernes
Yeah, but that uses carefully calibrated relations with the time evolution at
different filters to significantly decrease the the observed spread in
luminosity.

Also, here they don't report on a Type Ia supernova (the ones useable as
standard candles because we ain't got anything else).

------
yread
What a strange press release. Energy measured in ergs, 100 solar masses
"incredibly massive" star?

~~~
goodcanadian
Ergs is pretty commonly used in physics. A 100 solar mass star is very
massive: 150 solar masses is about the theoretical limit for a star.

~~~
pdkl95
~150 solar masses is the Eddington limit[1] where the outward luminosity
pressure becomes greater than the inward gravitational pressure holding the
star together. Stars probably cannot _grow_ past this size through normal
accretion. However, a few[2] stars have been estimated to have masses much
greater than 150 solar masses, up to R136a1 [3] with an estimated 315 solar
masses.

[1]
[https://en.wikipedia.org/wiki/Eddington_luminosity](https://en.wikipedia.org/wiki/Eddington_luminosity)

[2]
[https://en.wikipedia.org/wiki/List_of_most_massive_stars#Lis...](https://en.wikipedia.org/wiki/List_of_most_massive_stars#List_of_the_most_massive_stars)

[3]
[https://en.wikipedia.org/wiki/R136a1](https://en.wikipedia.org/wiki/R136a1)

