Comments on: Star Endured Unique Explosion That Didn't Destroy

By: Don Alexander

Don Alexander — Mon, 15 Sep 2008 13:57:26 +0000

@RetardedFishFrog: The conditions needed to create a black hole can only oocur upon total core collapse – and that destroys the star completely. Furthermore, a black hole which, upon explosion, would release enough energy to create this effect would be stable for much longer than the lifetime of the universe (and hence the star…)

@Richard Diaz: Eta IS a binary system! This was shown more than ten years ago. The secondary seems to be a B type star. Not sure what the mass is, maybe 10 solar masses or so. The orbit is 5.2 years. They form a colliding wind binary, and, yes, the orbit is eccentric, each time the stars approach each other, the X-ray signature and the spectrum change. So, you had some good ideas, but I fear the secondary is not responsible for the explosive behaviour. You probably need much larger tidal forces for that, for example when a massive star passes really close to a supermassive black hole, it may explode.

By: Richard Diaz

Richard Diaz — Sun, 14 Sep 2008 23:40:07 +0000

Maybe Eta Carinae is actually a binary massive star. 1 with 80+ the mass of the Sun and the other 30+ times the mass of the Sun and they orbit each other in extremely eccentric orbits with a period of 165 years or so and in every orbit, each star's outer layers hits the outer layers of the other star, which releases a lot of matter into space, while the gravity between the 2 stars tug on each other star's core, which releases extreme amounts of energy into space from their cores into space making it appear as an explosion smaller than a supernova every 165 years or so. Or less years every time. Possibly when they nearly collide, their gravity doesn't let the other companion get far as it did last time.

By: RetardedFishFrog

RetardedFishFrog — Sat, 13 Sep 2008 02:21:16 +0000

Correction – scale the size of the black hole up from microscopic to whatever size it would have to be to create an explosion that fits the observable data.

By: RetardedFishFrog

RetardedFishFrog — Sat, 13 Sep 2008 01:30:15 +0000

Perhaps at such large stellar masses, the pressure pushing out on the star is not always enough to keep some of the mass from collapsing into a microscopic black hole. The black hole would be very short-lived and explode within the star creating the stellar explosion.

By: Don Alexander

Don Alexander — Thu, 11 Sep 2008 19:08:32 +0000

@John: Not by long shot! Anyway, Eta is an ultramassive binary star, it's pretty much impossible that planets were able to form there.

By: John Mendenhall

John Mendenhall — Thu, 11 Sep 2008 14:57:37 +0000

Is an infalling hot Jupiter big enough to trigger one of these?

I doubt it, but . . .

By: ESA Exile

ESA Exile — Thu, 11 Sep 2008 07:54:51 +0000

Further to Don's comment, as the matter is accreted on to the surface it has to come from beyond the white dwarf. As a result novae only occur in binary systems, and close binaries at that!

By: Don Alexander

Don Alexander — Thu, 11 Sep 2008 00:24:09 +0000

A nova is the thermonuclear ignition of accreted matter on a white dwarf's surface. Kind of like pouring gasoline on a hot stove burner…

By: Tyler Durden

Tyler Durden — Thu, 11 Sep 2008 00:18:14 +0000

The way I always understood it, a Supernova was the death of a star, either forming a black hole or just ejecting its mass in all directions.

A Nova (not super) was a stellar explosion which greatly increased the brightness of the star briefly, but did not kill the star/expend all fuel.

By: Don Alexander

Don Alexander — Thu, 11 Sep 2008 00:16:54 +0000

Nathan, Nathan, Nathan. I am so envious of you!! Not only do you already have umpteen first-author papers, but now your very own Nature paper.

Fascinating result!! Keep up the good work.

I will not that if the pulsed pair instability mechanism is the correct interpretation, it would need to work on very different timescales. It's been over 150 years since the Great Outburst of Eta Car, but SN 2006jc went bang just two years after its own LBV eruption.