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John Jaksich
2008-Nov-28, 07:16 PM
According to what I am told, the Milky Way is past due for a Supernova explosion? Besides Betelgeuse, does anyone in the forum have any idea which star might be next?

Cheers

01101001
2008-Nov-28, 08:47 PM
According to what I am told, the Milky Way is past due for a Supernova explosion?

Wait. Let me check my social calendar.

Meanwhile, you can peruse: Why is a nearby supernove (far) overdue? (http://www.bautforum.com/questions-answers/38655-why-nearby-supernove-far-overdue.html)

Please hold...

By the way, how overdue do you think one is? A remnant of one was seen last May, interesting because of its youth. National Geographic: Youngest Supernova in Milky Way Found (http://news.nationalgeographic.com/news/2008/05/080514-supernova.html).

Here's an estimate: Universe Today: A Supernova Every 50 Years (http://www.universetoday.com/2006/01/05/a-supernova-every-50-years/).


According to what I am told, the Milky Way is past due for a Supernova explosion? Besides Betelgeuse, does anyone in the forum have any idea which star might be next?

If we know the star, it would be a nearby one, and not merely a member of the Milky Way. Nearby supernovae would have to be far less frequent. Do we know that frequency? Must be a long while between them on average.

trinitree88
2008-Nov-29, 07:17 PM
Alnitak. see:http://www.skyfactory.org/ngc2024/ngc2024.html It already shows some iron lines and with ~20 solar masses, an iron core may be developing. It isn't a guarantee, as mixing may be the line emission, though...and I already coughed up a bet to Antoniseb on this one....so I'm putting it at 2012. At a distance of ~ 800 light years, we'd get a real nice show, and survive it quite nicely. Stars within a few light years might harbor planets not so lucky. It should actually rain on them...or snow, from the water made in the boom... as it did here when the Local Bubble was carved out....and some iron-60 may make it's way into their ocean sediments too.

John Jaksich
2008-Nov-29, 07:39 PM
Dear trinitree,

The link that you provided seems to be broken; however, I found the following link...although it is not as informative as yours:

www.astro.uiuc.edu/~kaler/sow/alnitak.html:)

Cheers...

Don Alexander
2008-Nov-29, 09:13 PM
trinitree, the iron fusion period of a massive core is extremely short and lasts maybe a day or so. No chance of dredging up any of that. And of course you will get iron lines, it's material left over from older supernovae. These are Population I stars, after all. The sun has iron lines in its spectrum - is it about to ge SN? Finally, Alnitak is a blue supergiant and clearly not yet at the end of its evolution. Though SN 1987A showed us that blue supergiants can explode too.

Betelgeuze is very probably much closer to going SN, and is also the closest star that will (of core-collapse, anyway, I'm not sure of the distance of RS Ophiuchi, which is a Type Ia candidate) definitely go SN.

Eta Carinae is a very strong candidate, as it is showing powerful instabilities that have already lead to explosive events.

Sher 25 near NGC 3603 is a good candidate too, it has already blown rings similar to those seen around Sanduleak -69 202, the SN 1987A progenitor.

Furthermore, some extremely massive stars near the Galactic Center, like the Pistol Star, will probably go "soon" - but with soon I mean within the next million years or so.

That said, within the next 10 - 20 million years, many bright stars in the sky will go SN. Most of Orion is going to blow, not just Betelgeuze, but also the complete Belt, Rigel, Meissa, Saiph, Na'ir al Saif (the star at the tip of the sword), and Theta Orionis 1C. Bellatrix seems to be on the border.

Deneb, Antares, Naos, Gamma-2 Velorum, and many, many others.

m1omg
2008-Nov-29, 10:11 PM
trinitree, the iron fusion period of a massive core is extremely short and lasts maybe a day or so. No chance of dredging up any of that. And of course you will get iron lines, it's material left over from older supernovae. These are Population I stars, after all. The sun has iron lines in its spectrum - is it about to ge SN? Finally, Alnitak is a blue supergiant and clearly not yet at the end of its evolution. Though SN 1987A showed us that blue supergiants can explode too.

Betelgeuze is very probably much closer to going SN, and is also the closest star that will (of core-collapse, anyway, I'm not sure of the distance of RS Ophiuchi, which is a Type Ia candidate) definitely go SN.

Eta Carinae is a very strong candidate, as it is showing powerful instabilities that have already lead to explosive events.

Sher 25 near NGC 3603 is a good candidate too, it has already blown rings similar to those seen around Sanduleak -69 202, the SN 1987A progenitor.

Furthermore, some extremely massive stars near the Galactic Center, like the Pistol Star, will probably go "soon" - but with soon I mean within the next million years or so.

That said, within the next 10 - 20 million years, many bright stars in the sky will go SN. Most of Orion is going to blow, not just Betelgeuze, but also the complete Belt, Rigel, Meissa, Saiph, Na'ir al Saif (the star at the tip of the sword), and Theta Orionis 1C. Bellatrix seems to be on the border.

Deneb, Antares, Naos, Gamma-2 Velorum, and many, many others.

I think the Pistol Star and the Gamma-2 Velorum are most likely to explode soon, except for Eta Carinae.
The most massive stars do not undergo red supergiant stages, they go to LBV (luminous blue variable) stage (extreme blue O class hypergiant) and then either explode (the most massive of them) or after the LBV stage go to Wolf-Rayet star stage and start shedding mass insanely, then exploding.Either way, it explodes into a gamma ray burts and a leaves a black hole with an accretion disk lasting millions of years.

So my list would be:
1.Eta Carinae - obviously, because the star is already halfway exploded
2.Peony Nebula star aka WR 102ka (evolved extreme Wolf-Rayet star) - this star has 150 solar masses, it is estimated that it started off with 175 solar masses, and it has a big nebula around it from the gases (25 Solar masses that it already expelled), this is not a good sign for the star...
3.HD 269810 - 150 solar masses, enuff said
4.LBV 1806-20 - obviously, a 120-200 solar mass blue monster 150x bigger than the Sun that is probably not gonna last long...
6.Gamma Velorum-2 - WR star, enuff said...

And other massive stars already mentioned, but IMHO these 6 have a real good chance of blowing up in our limetimes...

PS- Also, the entire Arches Cluster ( http://en.wikipedia.org/wiki/Arches_cluster ), just 100 ly from the center of the Galaxy is ready to blow up with its supermassive stars with 100-150 Solar masses...Also the Quintuplet Cluster is gonna blow up too ( http://en.wikipedia.org/wiki/Quintuplet_cluster )...it contains the Pistol Star btw...

trinitree88
2008-Nov-30, 04:42 PM
For the rookies in the supernova business, a little animation goes a ways to seeing it happen, see:http://library.thinkquest.org/25763/supernova.htm This animation does not include the axisymmetric flows seen in the debris from the real ones...bear that in mind, it's more barrel shaped than they indicate, but it's a start.


Don A. Most of the models of type 2's that I've seen have the timescale for the accumulation of the iron core from six months to up to ~ 10 years before she blows. Do you have a reference for this call for a day or so? Thanks, pete.

There is an error in the link..neutrinos were detected by Cowan & Rheines at the Savannah River nuclear plant, long before supernova 1987a. little oversight there...see;http://www.ps.uci.edu/physics/news/nuexpt.html

PraedSt
2008-Nov-30, 05:16 PM
Rookie, that's me. And you're right- great link. Thanks!

Romanus
2008-Dec-06, 04:16 PM
My op is that the next supernova will be none of the currently-favored candidates, but will instead be some distant, dim (or perhaps invisible at optical lengths) supergiant with a long-forgotten catalogue number, if that. Love to be proven wrong, though!

Actually, I wouldn't be surprised at all if the next SN we see is in M31 or M33; the former hasn't had one in over 120 years, and to my knowledge there's never been one observed in M33, in spite of its young stellar population. An average-brightness core-collapse SN would be an easy binocular object in either one.