Astronomers Awaiting 1a Supernova

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."

Actually

[ArchieBunker]

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

How long?!?

[TJ_Phazerhacki]

This seems interesting only in the way that a man shouting about the end of the world downtown is. The timeframe involved isn't really anything to get excited about...

Re:Actually

[Zindagi]

Google search brings up an approximate distance of 2000 light years. Thats fairly close -- but dont think the explosion can fling out material this far.

The star is 1,950 light years away?

[Mantrid42]

http://en.wikipedia.org/wiki/Supernova#Impact_of_s upernovae_on_Earth [wikipedia.org]

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.

1572 is a long time ago?

[maximthemagnificent]

On the timescales they're discussing the 1572 sighting was "last year"!

Re:Actually

[diskis]

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.

Re:The star is 1,950 light years away?

[Khomar]

If you look at the next paragraph, things don't look so bleak.

Recent estimates predict that a Type II supernova would have to be closer than 8 parsecs (26 light years) to destroy half of the Earth's protective ozone layer.[2] Such estimates are mostly concerned with atmospheric modelling and considered only the known radiation flux from SN 1987A, a Type II supernova in the Large Magellanic Cloud. Estimates of the rate of supernova occurrence within 10 parsecs of the Earth vary from once every 100 million years [3] to once every one to ten billion years.[4]

While this supernova could affect the earth, the affect would probably not be catastrophic. We would probably have a great light show and some communication interference, but our existence would not be threatened.

Re:The star is 1,950 light years away?

[KylePetty]

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 [sciencenews.org] 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.

Re:Gamma Ray burst = earth fried

[istartedi]

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.

Who the fuck modded this insightful?

[Anonymous Coward]

is this the discovery channel version of slashdot where pointing out the obvious is seen as informative? Come on, this isn't an eigth grade earth and space science class.

Range of lethality

[Short Circuit]

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?

It would be nice if we got one....

[Starker_Kull]

We've had supernovas recorded throughout human history; Wikipedia lists ones occuring in our galaxy (meaning, close enough to be easily observable) in 1006, 1054, 1181, 1572, 1604, and I remember from other sources that several were observed during Roman times. It seems that we've been "unlucky" in that ever since we've started to have precision astronomical instruments, we haven't had one go off in our galaxy. It would be really interesting if we would finally get one in modern times - and since they seem to go off about every 200 years or so, it doesn't seem that unlikely we might get one in our lifetimes. So here's to a little optimism!

Re:Gamma Ray burst = earth fried

[klaun]

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.

Re:Penny-Arcade Found a Supernova?

[Anonymous Coward]

Supernovae are observed all the time - the universe is a big place. The vast majority are observed by automated telescopes & image-recognition software, and occured in faraway galaxies. The most recent supernova that was close by was SN1987A, which occured in the Large Magellanic Cloud, a companion galaxy of the Milky Way. It was discovered by Francisco Garcia Diaz, and was a Type II supernova.

Tycho Brahe was the last person to discover a Type Ia supernova.

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[account_deleted]

Comment removed based on user account deletion

Aim matters

[Tablizer]

I believe the danger depends on where the star is "aimed". Magnetic fields focus the energy at the poles so that much of the energy is directed in narrow beams of radiation. If the star is fairly near and the "pole beam" is aimed at Earth, we may be fried. Some describe it as Cosmic Russian Roulette.