Hypernovae and Gamma Ray Bursts

[Pete]

What would a hypernova event look like from a direction away from the GRB axis?

Would it look like a supernova? Would the star simply wink out of existence?

Is Eta Carinae fated to become a hypernova? On Earth, will Eta Carinae's "exit" be a non-event, a wondrous visual spectacle, or a catastrophe?

[Pete]

Hmmm... what's a Wolf-Rayet star? Are these the only stars that could become hypernovae (according to current best theory)? Is Eta Carinae a Wolf-Rayet star?

[Starthane Xyzth]

I believe a star goes through the Wolf-Rayet phase whilst still forming, before it reaches the main sequence. It's characterised by an intense stellar wind, which helps to drive away the last of the primordial pre-stellar nebular, and may strip the original atmospheres from small, inner planets (such as the early Earth, which may once have possessed a substantial envelope of hydrogen and helium).

Away from the directional GRB jets, a hypernova would probably look like a particularly powerful supernova. Eta Carinae is an extremely massive and unstable luminous blue variable, which may or may not become a hypernova as such - that depends on how abruptly and how completely its core collapses. It might lose so much mass from its outer envelope beforehand that the inevitable explosive suicide will be dampened. And if it does form a GRB, the odds are against one of its polar jets being directed straight at the Solar System.

Yet if was so oriented... the effect on Earth is entirely dependent upon range. Am I right in thinking that Eta carinae is over 6000 light years distant?

[curioucity]

excuse me, did you say that hypernova is a type of stellar blast which happens to a young star?

[TruthSeeker]

excuse me, did you say that hypernova is a type of stellar blast which happens to a young star?
Yes, it sounds like it. I guess it is because the star is unstable. Kinda like the RR Lyrae that pulsates and thatn shoots out its outer envelopes. If a big young star is variable, it probably explodes just like the old ones. I haven't seen that on my astronomy calls, and in fact in any book I've ever read. Sounds interesting.

Reminds me of the supernova 1987a in the LMC. That was a young star too. Was that a hypernova? Do we already know about what happened there?

[curioucity]

thanks. the truth is, the term hypernova itself is very new to me....... too new, in fact, today's the first time I read the word......

[TruthSeeker]

thanks. the truth is, the term hypernova itself is very new to me....... too new, in fact, today's the first time I read the word......
Me too. But you can use some logic to understand it.

So don't believe in me. Wait to see the ones that started the thread to reply. I might be wrong, ya know... ;)

[eburacum45]

These hypernovae explode because they are so big they rush through their main sequence lifetime in a million years or so-

in fact Eta Carina is already off the main sequence- although if it will become a supernova, hypernova, or whatever is not yet clear.

SF worldbuilding at
http://www.orionsarm.com/main.html

[Starthane Xyzth]

excuse me, did you say that hypernova is a type of stellar blast which happens to a young star?

:o What I meant was, a hypernova - like a supernova - is an explosion which ends a star's life, after it has been through the main sequence and subsequent supergiant phases. However, a star massive enough to form a hypernova will, as erburacum45 said, live very fast and die "young." Certainly, young when compared with the vast majority of stars, who age gracefully and shine through gigayears.

[TruthSeeker]

It still has to go through the red giant region before it becomes a supernova (or hypernova, whatever). Makes me wonder about 1987a... :rolleyes:

Btw.... is a hypernova bigger then a supernova? Supernovae are already pretty big... :eek:

[eburacum45]

http://en.wikipedia.org/wiki/Hypernova

http://en.wikipedia.org/wiki/Supernova

(hypernova is not really a generally accepted term- as these extra large supernovae are associated with gamma ray bursts they tend to be called GRB events)

-----------------------
SF worldbuilding at
http://www.orionsarm.com/main.html

[Bachus]

(hypernova is not really a generally accepted term- as these extra large supernovae are associated with gamma ray bursts they tend to be called GRB events)
Weren't GRB events also linked to 2 black holes crushing into eachother? (or a black hole and a neutron star?) This is what I heard during a lecture on GRB's)

[Pete]

There's still question marks around GRBs. Hypernovae are suspected as the most common cause, but they may not explain all of them. There also may be more than one kind of GRB, as some are much shorter than others.

[Starthane Xyzth]

There also may be more than one kind of GRB, as some are much shorter than others.

:D Who knows... some GRBs may still be the exhaust burns of antimatter engines on alien starships.

[curioucity]

Confuses me........ so now everyone sez that hypernova is simply supernova done by a super big star? Ah well.....

[Pete]

Sort of... Read about it at NASA (http://www.gsfc.nasa.gov/topstory/2003/0618rosettaburst.html)