Modern day supernova

[Undesired Walrus]

I was reading about SN_1054 (http://en.wikipedia.org/wiki/SN_1054), a supernova Sagan said in Cosmos was so bright it could be seen by day and read by at night.

Do we know when the next one like this is likely to occur, or could it be any day, occuring without any guesswork? How bright would it have to be to see at day and read by at night?

How would society react?

[ArcturusA]

First, a couple of handy links:

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

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

The kind of prediction we can manage is on the scale of thousands to millions or hundreds of million years.
One to watch is Betelgeuse. If that goes off (and it could within the next thousand years apparently), it'll outshine the moon.

[Jack by the hedge]

Another could happen any time - completely unpredictable*.
"Daylight visible" is a bit vague. You could call Venus daylight visible, if you allow the extreme ends of the day (although you could hardly read by it).

I wonder how high in the sky the nova was at sunrise/sunset. Since the Chinese noted it on 4th July 1054, I guess someone with a handy astronomial resource at their fingertips could tell us where the crab nebula was in the sky relative to the sun at the time...

*On a human timescale, that is.

[Belz...]

Betelgeuse would be nice.

[Dancing David]

Another could happen any time - completely unpredictable*.
"Daylight visible" is a bit vague. You could call Venus daylight visible, if you allow the extreme ends of the day (although you could hardly read by it).

It also takes a bit of practice to see it, even with binocs, I have quite a few times. It is easy to spot even once the sun is up, it is just frustrating.

[SonOfLaertes]

Betelgeuse would be nice.

No, not Betelguese! It's like an old friend going away for the summer and returning every fall. It's in the constellation I used to get my niece's and nephew's interested in the night sky, for years afterward my young niece would point up and say "Beetle-Juice!" with a big smile on her face. They are adults now and still point stars out to me and name them.

I guess I could live with it if it was spectacular enough. But it better be good!

[amb]

Were in a fairly stable part of the galaxy, our nearest neighbor Alpha Centaurus is 5 light years away, that could destroy life here if it blew itself apart, but not likely to go supernova. But none of the stars within say, a hundred light years are likely to blow up in the next 5-10 million years.

[aggle-rithm]

Were in a fairly stable part of the galaxy, our nearest neighbor Alpha Centaurus is 5 light years away, that could destroy life here if it blew itself apart, but not likely to go supernova.

It's not nearly big enough, is it? The vast majority of starts aren't even as big as our own Sun, and that's not big enough.

[The Drain]

This got me thinking about what damage a nearby supernova could do to us, and might that include Betelgeuse, which is 'only' 640 LY away.

It turns out that the key apparently is not just the distance of the supernova from Earth but also the direction of the star's axis with relation to us.

This (reassuring) quote from the wiki entry on Betelgeuse (http://en.wikipedia.org/wiki/Betelgeuse): Since its rotational axis is not toward the Earth, Betelgeuse's supernova will not cause a gamma ray burst (http://en.wikipedia.org/wiki/Gamma_ray_burst) in the direction of Earth large enough to damage its ecosystems (http://en.wikipedia.org/wiki/Ecosystem).

The article goes on to say that Betelguese has been observed by the Mt Wilson Observatory to be shrinking since 1993 at an increasing rate. The average speed at which it is shrinking over the last 15 years is 470-490mph.

I predict the woos will have a field-day when Betelgeuse goes ka-boom - especially if it happens anytime between now and 2012!

[amb]

Supernovas are very rare events. I doubt we will ever see a nearby one in the next say, 1 million years. Betelgeuse may have already gone supernova, but we will not see any sign of it for hundreds of years if at all.

[icerat]

It's probably important that this type of information is well known though. I could imagine wide spread panic in some places when this happens. I've read some reports that it may be up to 1000 times brighter than the moon when the actual explosion light reaches us. Can you imagine how the rapturites and others would react to that? And the 2012 doomsdayers?

This could happen right now, in the next hour, tonight, tomorrow, any time. Remember Nightfall!

[icerat]

Hey, well this is a fun find!

Make money of your friends by getting a few hours head start and betting a huge explosion in the sky will occur! :D

SuperNova Early Warning System (http://snews.bnl.gov/)

Apparently the neutrinos will hit us a few hours before the light, and people are watching ....

[Jack by the hedge]

I think the reports of reading by the nova's light at night must be hyperbole.

According to Wikipedia, the remnant of the 1054 supernova is the Crab Nebula (http://en.wikipedia.org/wiki/Crab_nebula), M1, in Taurus. And their first reference (http://www.seds.org/messier/more/m001_sn.html)says Chinese astronomers first noted seeing it on 4th July 1054, and that it was daylight visible for 23 days.

I looked for a calculator to see where in the sky it appeared relative to the sun on that date: according to this calculator (http://www.fourmilab.ch/cgi-bin/Yoursky)(as best I can drive it), on that day M1 was barely 8° away from the sun from Earth's POV, so it would only rise 40 minutes before the sun itself. Reading by its light at night doesn't make any sense. To be daylight visible, it must have been amazingly bright.

Or I'm doin' it wrong.

[Undesired Walrus]

What would the event look like? Would it suddenly burst into existence and briefly light up (If it was at night) the entire sky, only to remain there for a few months?

It would be interesting to see how the media would report it. And for how long.

Are there any bible quotes about a 'bright light' predicting the end?

[Undesired Walrus]

I think the reports of reading by the nova's light at night must be hyperbole.


But it's not implausible that some star could be effectively used as reading light?

[Jack by the hedge]

But it's not implausible that some star could be effectively used as reading light?

Not implausible at all. The sun just happened to be almost exactly between this supernova and us, so it never appeared in the night sky for the few weeks it was at it's brightest.

[Aepervius]

Supernovas are very rare events. I doubt we will ever see a nearby one in the next say, 1 million years. Betelgeuse may have already gone supernova, but we will not see any sign of it for hundreds of years if at all.

IF wiki is to be believed, there is one about every 50 years. So not so rare.
(On average, supernovae occur about once every 50 years in a galaxy the size of the Milky Way.[5])

About beltegeuse, with about 935 time the solar radius, at 7.10^8 meter the radius, and a shrinking of 220 meter s-1, that would mean with 94 years the radius would be zero (935*7.10^8/220 in years). naturally that is not possible the star would go supernovae long before that.

Still I doubt that 2 years will make a difference.

[BenBurch]

But it's not implausible that some star could be effectively used as reading light?

You can read by Venus at its brightest.

So, not implausible whatsoever.

[MG1962]

The article goes on to say that Betelguese has been observed by the Mt Wilson Observatory to be shrinking since 1993 at an increasing rate. The average speed at which it is shrinking over the last 15 years is 470-490mph.

I predict the woos will have a field-day when Betelgeuse goes ka-boom - especially if it happens anytime between now and 2012!

Betelguese is a semi regular variable star so this sort of shrinkage and expansion is not unusal. I believe it is on something like a 27 year cycle. The has been a lot of discussion about where exactly the star is in its cycle. Because we can not directly observe the core of stars, there have been arguments that Betelguese may already be in its iron phase now

[MG1962]

I think the reports of reading by the nova's light at night must be hyperbole.

According to Wikipedia, the remnant of the 1054 supernova is the Crab Nebula (http://en.wikipedia.org/wiki/Crab_nebula), M1, in Taurus. And their first reference (http://www.seds.org/messier/more/m001_sn.html)says Chinese astronomers first noted seeing it on 4th July 1054, and that it was daylight visible for 23 days.

I looked for a calculator to see where in the sky it appeared relative to the sun on that date: according to this calculator (http://www.fourmilab.ch/cgi-bin/Yoursky)(as best I can drive it), on that day M1 was barely 8° away from the sun from Earth's POV, so it would only rise 40 minutes before the sun itself. Reading by its light at night doesn't make any sense. To be daylight visible, it must have been amazingly bright.

Or I'm doin' it wrong.

No you are doing it right. 40 minutes before sunrise is a pretty long time, most bright naked eye comets are closer. The actual light curve of the supernova is a bit of an unknown. M1 as an event is a bit problematic. Some evidence points to one type of supernova, others point to different conclussions. Resolving this, resolves the brightness and length of daylight observation.

Also with the reading at night. Remember they would not be reading a Dan Brown novel. The scripts I have seen from that era point to a much larger and distinctive font

[MG1962]

Hey, well this is a fun find!

Make money of your friends by getting a few hours head start and betting a huge explosion in the sky will occur! :D

SuperNova Early Warning System (http://snews.bnl.gov/)

Apparently the neutrinos will hit us a few hours before the light, and people are watching ....

And it works! When Supernova 1987A went off. Bells were ringing all over the planet about 4 hours before. Trouble is the detection system is not directional. It took a janitor in Chile to actually spot the star

[Grizzly Bear]

It's not nearly big enough, is it? The vast majority of starts aren't even as big as our own Sun, and that's not big enough.

Alpha Centauri (http://en.wikipedia.org/wiki/Alpha_Centauri) is a triple binary system if memory serves, one of them is a dwarf star while the other two are definitely won't be of any consequence as far as supernovas are concerned. :)

[icerat]

About beltegeuse, with about 935 time the solar radius, at 7.10^8 meter the radius, and a shrinking of 220 meter s-1, that would mean with 94 years the radius would be zero (935*7.10^8/220 in years). naturally that is not possible the star would go supernovae long before that.

Assuming no major variations in shrinking/expansion (anyone know the astrophysics on this?) your calcs would imply that Betelgeuse probably went nova a few hundred years ago and there's a good chance we'll get the news in our lifetime :wackyjiggy:

[ben m]

And it works! When Supernova 1987A went off. Bells were ringing all over the planet about 4 hours before. Trouble is the detection system is not directional. It took a janitor in Chile to actually spot the star

Actually, that's not how it happened. There was no supernova "warning system" in 1987---these detectors were running, yes, but nobody looked at their data in real time.

The supernova was first noticed by several optical observers, including (famously) Duhalde. Later, after the IAUC telegrams had gone around, the neutrino people scanned through the previous days' data and saw that there had been a burst.

The new SNEWs system is meant to do it the other way around---if the neutrino experiments see something, they'll email it out to the astronomers first.

[Fnord]

Actually, that's not how it happened. There was no supernova "warning system" in 1987---these detectors were running, yes, but nobody looked at their data in real time.

The supernova was first noticed by several optical observers, including (famously) Duhalde. Later, after the IAUC telegrams had gone around, the neutrino people scanned through the previous days' data and saw that there had been a burst.

The new SNEWs system is meant to do it the other way around---if the neutrino experiments see something, they'll email it out to the astronomers first.
.
Exactly.

The neutrino burst was generated about 3 hours before the visible light emissions began to rise, and they travelled at the same velocity. The burst itself lasted only about 13 seconds, and consisted of only 24 neutrinos.

I'm sure that the "Janitor Detects Supernova" story is largely apocryphal.

[RussDill]

Assuming no major variations in shrinking/expansion (anyone know the astrophysics on this?) your calcs would imply that Betelgeuse probably went nova a few hundred years ago and there's a good chance we'll get the news in our lifetime :wackyjiggy:

As MG1962 noted, its a cyclical star. Playing the odds, its much more likely that the change in size is part of that cycle, not that we just happened to start looking in a small window of time before it goes supernova (at the only star other than the sun that can be resolved as a disc)

[amb]

IF wiki is to be believed, there is one about every 50 years. So not so rare.
(On average, supernovae occur about once every 50 years in a galaxy the size of the Milky Way.[5])

About beltegeuse, with about 935 time the solar radius, at 7.10^8 meter the radius, and a shrinking of 220 meter s-1, that would mean with 94 years the radius would be zero (935*7.10^8/220 in years). naturally that is not possible the star would go supernovae long before that.

Still I doubt that 2 years will make a difference.

But the point in the spiral we are part of is around 30 thousand light years from the center bulge of the galaxy where most of the stars are, and therefore, most of the S/Ns occur.

[MG1962]

Actually, that's not how it happened. There was no supernova "warning system" in 1987---these detectors were running, yes, but nobody looked at their data in real time.

I recall reading at the time - might have been the old Omni magazine. Where a number of nutrino detectors showed unexpected activity, but until the supernova showed, they didn't know what to make of it. Basically the incredibly long lead time threw them off.


The supernova was first noticed by several optical observers, including (famously) Duhalde. Later, after the IAUC telegrams had gone around, the neutrino people scanned through the previous days' data and saw that there had been a burst.

At the time Duhalde was described as the janitor at the place (obviously wrong) The story goes that Shellton spoke to Duhalde when he arrived at the observatory to begin the nights work when Duhalde casually mentioned the new star. Shellton raced inside to take the photos and the rest became urban myth

[MG1962]

But the point in the spiral we are part of is around 30 thousand light years from the center bulge of the galaxy where most of the stars are, and therefore, most of the S/Ns occur.

The location of the star means less than the type of star. Classic type 1b and type II are extremely common in rich star formation areas. Generally these stars are high mass and unstable - an explosion waiting to happen.

In the cores of most galaxies, these types of stars are long gone, have spent their fuel long before most stars in the region had even settled down

[shadron]

This got me thinking about what damage a nearby supernova could do to us, and might that include Betelgeuse, which is 'only' 640 LY away.

It turns out that the key apparently is not just the distance of the supernova from Earth but also the direction of the star's axis with relation to us.

The difference is between experiencing a supernova or experiencing a gamma ray burster. They are the same phenomenon, both create a cone of gamma rays shooting out perpendicular to the rotation of the former star for maybe 10 seconds or so as the star explodes. You don't want to be within 100 light years or so of a supernova; a GRB can wallop the planet hard from 8000 light years or so. It's not quite a shotgun blast; the cones appear to usually be about 3 degrees in angular size, and at 8000 lyr would be a near-cylinder 50 light years in radius.

One theory has it that the worst extinction event of all time was a 10-second GRB that blasted us from about 5000 light years away. We won't know whether the theory is true until we get to the moon and see if we can find remnants of the GRB's radioactive paw print on the surface.

Supernovas are very rare events. I doubt we will ever see a nearby one in the next say, 1 million years. Betelgeuse may have already gone supernova, but we will not see any sign of it for hundreds of years if at all.

It was estimated somewhere that a visible supernova should happen in our galaxy every 400 years or so. The Crab nebula SN was in 1074. We had Tycho's supernova in 1582, and then Kepler's in 1604, and now we are about due for another one, on the average. SN1987A was in the LGM, not in our galaxy, though it was eyeball visible.

If Betelgeuse goes supernova, oh, yeah, we'll see it. Crab Nebula SN was 6500 light years away, and had magnitude -6; Tycho's star (magnitude -4) was about 5000 light years away, and Kepler's (magnitude -2.5) was 20,000 light years; Betelgeuse is 520 light years, and has 15 solar masses, bordering on the mass required for black hole formation. For comparison Venus has a maximal magnitude of -4. Each step in magnitude is about 2.5 time in apparent brightness, with the lesser values being higher brightness; on that scale the sun is about -27, the moon -12.6. I would think Betelgeuse would outshine the moon for a while.

[shadron]

Actually, that's not how it happened. There was no supernova "warning system" in 1987---these detectors were running, yes, but nobody looked at their data in real time.

The supernova was first noticed by several optical observers, including (famously) Duhalde. Later, after the IAUC telegrams had gone around, the neutrino people scanned through the previous days' data and saw that there had been a burst.

The new SNEWs system is meant to do it the other way around---if the neutrino experiments see something, they'll email it out to the astronomers first.

The story of the discovery: http://www.aavso.org/vstar/vsots/0301.shtml

An astronomer in Chile found it on a plate he had just developed, and then he walked outside and found it with his naked eyes.

[shadron]

As MG1962 noted, its a cyclical star. Playing the odds, its much more likely that the change in size is part of that cycle, not that we just happened to start looking in a small window of time before it goes supernova (at the only star other than the sun that can be resolved as a disc)

However, they are detecting Ni56 and Co56 in Betelgeuse. These both decay into iron. This is (I'm told) a pretty sure sign that the end is nigh; the core is cooking up it's last batch of fusion products and they've had time to make it to the star's atmosphere, and Betelgeuse is showing those isotopes.

Of course, no one identified what "nigh" is.

[shadron]

No you are doing it right. 40 minutes before sunrise is a pretty long time, most bright naked eye comets are closer. The actual light curve of the supernova is a bit of an unknown. M1 as an event is a bit problematic. Some evidence points to one type of supernova, others point to different conclussions. Resolving this, resolves the brightness and length of daylight observation.

Also with the reading at night. Remember they would not be reading a Dan Brown novel. The scripts I have seen from that era point to a much larger and distinctive font

Also note that the sun moves at a rate of a degree a day, so within a month is will be 30 degrees away from the nova. The sun is in Taurus around June 1, and the nova happened in July, so 8 degrees is probably a pretty good figure.

[MG1962]

However, they are detecting Ni56 and Co56 in Betelgeuse. These both decay into iron. This is (I'm told) a pretty sure sign that the end is nigh; the core is cooking up it's last batch of fusion products and they've had time to make it to the star's atmosphere, and Betelgeuse is showing those isotopes.

Of course, no one identified what "nigh" is.

The only thing that suggests this particular contraction is not 'nigh' is the reported speeds of the contraction. 400 odd miles and hour is way slower than we would be expecting to see.

And I agree if you are seeing nickel, its time to go. I recall a very old article, pre 1987A that suggested a star once reaching the iron cycle can have its life span measured in hours. I wonder if this still holds true, or if they now think the stars can hang on longer

[ArcturusA]

The only thing that suggests this particular contraction is not 'nigh' is the reported speeds of the contraction. 400 odd miles and hour is way slower than we would be expecting to see.

Yeah, the star should collapse in something a little longer than the dynamical time scale (http://en.wikipedia.org/wiki/Dynamical_time_scale), which for Betelgeuse is around four months. But at a constant speed of 200m/s it'd take around 100 years.

[MG1962]

Yeah, the star should collapse in something a little longer than the dynamical time scale (http://en.wikipedia.org/wiki/Dynamical_time_scale), which for Betelgeuse is around four months. But at a constant speed of 200m/s it'd take around 100 years.

Would there be still that much pressure? Just doing it back of the enevelope based on a diameter of 5 AU and using free fall, I get a result of about 15 hours or so