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How bright would Eta-Carinae supernova be?
If Eta Carinae goes supernova in our lifetime would it be bright enough to outshine venus? Eta Carinae is more than 8,000 light-years away. Is there a way to prediect this? I think it would be an awesome site to see, if it went off in our lifetime. Fee |
#2
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How bright would Eta-Carinae supernova be?
Not precisely, but sure. eta Carinae, when it goes, will be a Type II
supernova and will brighten probably to something in the neighborhood of absolute magnitude -18 or -19. (Maybe toward -19 since it's so big?) That means that it would be magnitude -18 or -19 if seen from a distance of 10 parsecs, which is about 32.6 light-years. With all the dust it has thrown off, that should be an impressive show, watching the light/shell expansion. Clear Skies Chuck Taylor Do you observe the moon? Try http://groups.yahoo.com/group/lunar-observing/ And the Lunar Picture of the Day http://www.lpod.org/ ************************************ It will not, of course, be that close (thankfully), but about 250 times further away. Objects that far away are about 12 magnitudes dimmer than they would be at 10 parsecs, so that eta Carinae will have an apparent magnitude of about -6 or -7, several times brighter than Venus. Brian Tung The Astronomy Corner at http://astro.isi.edu/ Unofficial C5+ Home Page at http://astro.isi.edu/c5plus/ The PleiadAtlas Home Page at http://astro.isi.edu/pleiadatlas/ My Own Personal FAQ (SAA) at http://astro.isi.edu/reference/faq.txt |
#3
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How bright would Eta-Carinae supernova be?
Fee Fillers wrote:
If Eta Carinae goes supernova in our lifetime would it be bright enough to outshine venus? Eta Carinae is more than 8,000 light-years away. Is there a way to prediect this? I think it would be an awesome site to see, if it went off in our lifetime. Not precisely, but sure. eta Carinae, when it goes, will be a Type II supernova and will brighten probably to something in the neighborhood of absolute magnitude -18 or -19. (Maybe toward -19 since it's so big?) That means that it would be magnitude -18 or -19 if seen from a distance of 10 parsecs, which is about 32.6 light-years. It will not, of course, be that close (thankfully), but about 250 times further away. Objects that far away are about 12 magnitudes dimmer than they would be at 10 parsecs, so that eta Carinae will have an apparent magnitude of about -6 or -7, several times brighter than Venus. Brian Tung The Astronomy Corner at http://astro.isi.edu/ Unofficial C5+ Home Page at http://astro.isi.edu/c5plus/ The PleiadAtlas Home Page at http://astro.isi.edu/pleiadatlas/ My Own Personal FAQ (SAA) at http://astro.isi.edu/reference/faq.txt |
#4
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How bright would Eta-Carinae supernova be?
wow Thanks for the info. I was looking for this on google, and couldnt find much! Thats a day i look forward too heh "Brian Tung" wrote in message ... Fee Fillers wrote: If Eta Carinae goes supernova in our lifetime would it be bright enough to outshine venus? Eta Carinae is more than 8,000 light-years away. Is there a way to prediect this? I think it would be an awesome site to see, if it went off in our lifetime. Not precisely, but sure. eta Carinae, when it goes, will be a Type II supernova and will brighten probably to something in the neighborhood of absolute magnitude -18 or -19. (Maybe toward -19 since it's so big?) That means that it would be magnitude -18 or -19 if seen from a distance of 10 parsecs, which is about 32.6 light-years. It will not, of course, be that close (thankfully), but about 250 times further away. Objects that far away are about 12 magnitudes dimmer than they would be at 10 parsecs, so that eta Carinae will have an apparent magnitude of about -6 or -7, several times brighter than Venus. Brian Tung The Astronomy Corner at http://astro.isi.edu/ Unofficial C5+ Home Page at http://astro.isi.edu/c5plus/ The PleiadAtlas Home Page at http://astro.isi.edu/pleiadatlas/ My Own Personal FAQ (SAA) at http://astro.isi.edu/reference/faq.txt |
#5
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How bright would Eta-Carinae supernova be?
Fee Fillers wrote:
wow Thanks for the info. I was looking for this on google, and couldnt find much! You can Google my web pages, but you can't Google me. Thats a day i look forward too heh Do you live in the southern hemisphere? The best view would be from there (and it cannot be seen at all from north of 30 degrees north latitude). Brian Tung The Astronomy Corner at http://astro.isi.edu/ Unofficial C5+ Home Page at http://astro.isi.edu/c5plus/ The PleiadAtlas Home Page at http://astro.isi.edu/pleiadatlas/ My Own Personal FAQ (SAA) at http://astro.isi.edu/reference/faq.txt |
#6
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How bright would Eta-Carinae supernova be?
Not precisely, but sure. eta Carinae, when it goes, will be a Type II supernova and will brighten probably to something in the neighborhood of absolute magnitude -18 or -19. (Maybe toward -19 since it's so big?) That means that it would be magnitude -18 or -19 if seen from a distance of 10 parsecs, which is about 32.6 light-years. It will not, of course, be that close (thankfully), but about 250 times further away. Objects that far away are about 12 magnitudes dimmer than they would be at 10 parsecs, so that eta Carinae will have an apparent magnitude of about -6 or -7, several times brighter than Venus. What if Eta Carinae was only as far as Vega (25 light years) and it did this? Would it hurt life on Earth? How bright would it be? Jim Beam |
#7
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How bright would Eta-Carinae supernova be?
Jim Beam wrote:
What if Eta Carinae was only as far as Vega (25 light years) and it did this? Would it hurt life on Earth? How bright would it be? That 25 light-years works out to about 8 parsecs. The apparent magnitude of eta Carinae would then be about -19. That's a few hundred times brighter than the Full Moon, with all of that light squeezed into a tiny point, too. You wouldn't be able to look at it without squinting. As bright as it would be, however, the Sun would still shine upon the Sun with a light 1,000 times brighter. So eta Carinae would put on a dazzling light show, but not affect life on Earth--if only visible light were to be considered. However, visible light is not the only light to be considered. As it so happens, supernovae emit a lot more high-energy radiation, relatively speaking, than the Sun does. The Sun peaks in the visible region, but the fusion processes bared by supernovae emit plenty of gamma rays. It is this radiation that would do the damage, if there is damage to be done. At that point, a lot depends on what eta Carinae is destined to do. If it blows up as a typical (though perhaps larger than average) Type II supernova, 8 parsecs might be *just* barely far enough to escape serious damage (though cancer and mutations would probably make a decent living). But eta Carinae is such an unusual case that no one feels quite certain just what it will do, exactly. Fortunately, it lives a lot further away than 8 parsecs, so the question is merely academic and not an actual concern. The Gum Nebula is the remnant of a supernova that exploded sometime in the late Stone Age and is centered only about 1,500 light-years (about 450 parsecs) away. At that distance, a typical supernova would appear to be about magnitude -10. What a sight that would have been--and a safe one at that--but there was no one to record it in writing. Brian Tung The Astronomy Corner at http://astro.isi.edu/ Unofficial C5+ Home Page at http://astro.isi.edu/c5plus/ The PleiadAtlas Home Page at http://astro.isi.edu/pleiadatlas/ My Own Personal FAQ (SAA) at http://astro.isi.edu/reference/faq.txt |
#8
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How bright would Eta-Carinae supernova be?
The Gum Nebula is the remnant of a supernova that exploded sometime in the late Stone Age and is centered only about 1,500 light-years (about 450 parsecs) away. At that distance, a typical supernova would appear to be about magnitude -10. What a sight that would have been--and a safe one at that--but there was no one to record it in writing. Thank you for your answer. Are there other Gum Nebula in waiting? Is the local area so well cataloged that we know there are no dangerous/or/close stellar explosions in our future? How long will Eta C. stay at it's intensely bright level once blowing up? JB |
#9
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How bright would Eta-Carinae supernova be?
Jim Beam wrote:
Are there other Gum Nebula in waiting? Is the local area so well cataloged that we know there are no dangerous/or/close stellar explosions in our future? How long will Eta C. stay at it's intensely bright level once blowing up? It's pretty unlikely that there is a Type II supernova waiting to happen within 10 parsecs. Within that range, there are no stars that are as massive as is thought to be needed: about 8 solar masses and up. That leaves Type Ia supernovae (there are Type Ib and Ic, but they are like Type II without hydrogen lines), which require a massive white dwarf (near the Chandrasekhar limit of 1.4 solar masses) and a companion star that feeds it with fusible mass. There aren't any of these within our local neighborhood either. There are white dwarfs with companions, to be sure, but either the white dwarfs are too small, or the companions are too far away, or both. Within the 450 parsecs that separate us from the center of the Gum Nebula, it's less certain. Certainly, Betelgeuse is expected to go supernova in the astronomically near future, but it's still more than far enough away to do no more than put up a good show. I'm sure there are other likely candidates. Because white dwarfs are so dim, Type Ia candidates are considerably harder to pick out at such distances. Type II supernovae, such as eta Carinae will one day be, have light curves that can be parametrized largely by just their mass. (Also their composition, but to first order that shouldn't matter.) Generally, they reach a peak after a few weeks or so, and stay fairly bright for a matter of weeks to months. They typically remain bright longer than Type Ia supernovae; this is because Type II supernovae still have some fusible hydrogen and helium to illuminate. I seem to recall that the light emitted by Type Ia supernovae are mostly because of the decay of heavier elements synthesized during the explosion (like nickel-56). Brian Tung The Astronomy Corner at http://astro.isi.edu/ Unofficial C5+ Home Page at http://astro.isi.edu/c5plus/ The PleiadAtlas Home Page at http://astro.isi.edu/pleiadatlas/ My Own Personal FAQ (SAA) at http://astro.isi.edu/reference/faq.txt |
#10
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How bright would Eta-Carinae supernova be?
What if Eta Carinae was only as far as Vega (25 light years) and it did this?
Would it hurt life on Earth? How bright would it be? Short answer: it would be apparent magnitude -15 or so; about 10,000 times fainter than the Sun, but brighter than the full moon. Very likely no major long-term effects on the biosphere. Long answer: http://stupendous.rit.edu/richmond/answers/snrisks.txt Michael Richmond |
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