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Astronomers Awaiting 1a Supernova

Posted by ryuzaki0 on from the really-excited-space-geeks dept.

Aryabhata writes to tell us BBC News is reporting that astronomers have sighted a star on the brink of a "1a" supernova. This opportunity presents the first chance astronomers have ever had to view a supernova of this magnitude up close. From the article: "They are so rare that the last one known in our galaxy was seen in 1572 by the great Danish astronomer Tycho Brahe, who first coined the term nova, for "new star", not realizing he was in fact witnessing the violent end of an unknown star. It has long been believed that type 1a supernovae are the death throes of a white dwarf star. But all modern ones have been so distant that it has not been possible to see what had been there beforehand."

8 of 204 comments (clear)

  1. Actually by ArchieBunker · · Score: 4, Interesting

    It happened long ago and the light is just now reaching us.

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    1. Re:Actually by diskis · · Score: 3, Interesting

      Yes it can.
      There is nothing between us and the star.
      If you were lifted out from the gravity well of our solar system, I bet you can hit the star with a rock.
      Or one rock out of billions thrown. Kinda hard to hit precisely at that distance.

  2. The star is 1,950 light years away? by Mantrid42 · · Score: 5, Interesting
    http://en.wikipedia.org/wiki/Supernova#Impact_of_s upernovae_on_Earth
    Speculation as to the effects of a nearby supernova on Earth often focuses on large stars, such as Betelgeuse, a red supergiant 427 light years from Earth which is a type II supernova candidate. Several prominent stars within a few hundred light years from the Sun are candidates for becoming supernovae in as little as 1000 years. Though spectacular, these "predictable" supernovae are thought to have little potential to affect Earth. Type Ia supernovae, though, are thought to be potentially the most dangerous if they occur close enough to the Earth. Because Type Ia supernovae arise from dim, common white dwarf stars, it is likely that a supernova that could affect the Earth will occur unpredictably and take place in a star system that is not well studied. One theory suggests that a Type Ia supernova would have to be closer than 1000 parsecs (3300 light years) to affect the Earth.

    Shit.

    1. Re:The star is 1,950 light years away? by KylePetty · · Score: 4, Interesting

      Before everyone goes nuts saying our goose is cooked. It appears that not all sources agree as to the distance of this star. While some sources claim the star is 1,950 light years away, others claim it is as much as 5,000 light years away. http://www.sciencenews.org/articles/20060722/fob8. asp On referring to RS Ophiuchi, ScienceNews states: "That finding could have two interpretations, suggests the report's coauthor Richard Barry of NASA's Goddard Space Flight Center in Greenbelt, Md. If the star system resides at about 5,000 light-years from Earth, then the emissions reflect a mysterious, dense reservoir of material surrounding the two stars. If the system lies at only about one-third that distance, then the emission may for the first time be revealing a short-lived epoch during which the white dwarf, soon after its outburst, becomes as bloated as its red giant partner." Sites like Space.com claim it is 5,000 light years away, while Wiki has it pegged at 1,950. Meanwhile, the Harvard Gazette reports that: "When do scientists think the Ophiuchi supernova will rock the universe? Of course, no one knows enough about what goes on out there to say. But the best guess is it will take thousands of years for the final bit of gas to accumulate and blow the white dwarf away. Meanwhile, these reports should stimulate many more astronomers to focus their attention on the constellation Ophiuchi." So... I think it's a bit premature to claim we are doomed.

  3. Re:Gamma Ray burst = earth fried by istartedi · · Score: 3, Interesting

    IANAExpertOnThisCrap, but... if the burst lasts less than 12 hours, at least a north-south slice of the planet would be spared. If it's just a few minutes, only half the planet would be "fried", and if the Pacific Ocean happens to be facing it, then it's only bad for the relatively small island population, but if Eurasia is facing it, that's gonna be really really bad.

    Of course, that's based on the event being near the plane of the ecliptic. If the event was near a pole, then one of either the North or South hemispheres is fried, the other is spared.

    I'm also assuming that the gamma rays aren't powerful enough to turn surface matter into radioactive isotopes that pollute the atmosphere and ocean, or to do that to the atmosphere itself. In that case, it's more proper to say that the Earth is poisoned, not fried.

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  4. Range of lethality by Short+Circuit · · Score: 4, Interesting

    I'm curious. At what range would a Type 1a supernova be lethal to life on Earth?

    As far as the size of the galaxy is concerned, 1,950 light-years is essentially in our back-yard. Keeping with scale, are we talking about a firecracker or a stick of dynamite?

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  5. Re:Gamma Ray burst = earth fried by klaun · · Score: 3, Interesting
    I'm also assuming that the gamma rays aren't powerful enough to turn surface matter into radioactive isotopes that pollute the atmosphere and ocean, or to do that to the atmosphere itself. In that case, it's more proper to say that the Earth is poisoned, not fried.

    I think your confusing types of radiation here. Gamma rays are electromagnetic radiation and will not create radioactive isotopes no matter how intense they are. Generally, what they are going to do is ionize atoms and heat things up. Damage to biologicals from Gamma rays is via ionization and heat effects.

    If there were a very intense neutron burst, that could potentially "activate" some materials, i.e. transmute them into a radioacive isotopes. However, neutron burst are not going to be something we have to worry about at this distance from the event.

  6. Re:It would be nice if we got one.... by mark_osmd · · Score: 3, Interesting

    The supernova that made the Cas A remnant is estimated at 1665AD or so. There was so much dust in the way that no one even saw it with the possible exception of the astronomer Flamsteed who recorded what he thought was a normal star there but when we look there today there's no star of the brightness Flamsteed saw. Dust can really dim a supernova so much that we don't see it, but since we're looking around with even neutrinos and radio that dust doesn't stop it'll be detected even if it's on the far side of the Galaxy.