Preview of a forthcoming supernova

Preview of a Forthcoming Supernova
Credit: ESA/NASA

( -- NASA's Hubble Telescope captured an image of Eta Carinae. This image consists of ultraviolet and visible light images from the High Resolution Channel of Hubble's Advanced Camera for Surveys. The field of view is approximately 30 arcseconds across.

The larger of the two stars in the Eta Carinae system is a huge and unstable star that is nearing the end of its life, and the event that the 19th century astronomers observed was a stellar near-death experience. Scientists call these outbursts supernova impostor events, because they appear similar to supernovae but stop just short of destroying their star.

Although 19th century astronomers did not have telescopes powerful enough to see the 1843 outburst in detail, its effects can be studied today. The huge clouds of matter thrown out a century and a half ago, known as the Homunculus Nebula, have been a regular target for Hubble since its in 1990. This image, taken with the for Surveys High Resolution Channel, is the most detailed yet, and shows how the material from the star was not thrown out in a uniform manner, but forms a huge dumbbell shape.

Eta Carinae is one of the closest stars to Earth that is likely to explode in a supernova in the relatively near future (though in astronomical timescales the "near future" could still be a million years away). When it does, expect an impressive view from Earth, far brighter still than its last : SN 2006gy, the brightest supernova ever observed, came from a star of the same type, though from a galaxy over 200 million light-years away.

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Citation: Preview of a forthcoming supernova (2012, February 27) retrieved 18 July 2019 from
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Feb 27, 2012
It is possible that the Eta Carinae hypernova or supernova, when it occurs, could affect Earth, about 7,500 light years away. It is unlikely, however, to affect terrestrial lifeforms directly, as they will be protected from gamma rays by the atmosphere, and from some other cosmic rays by the magnetosphere. The damage would likely be restricted to the upper atmosphere, the ozone layer, spacecraft, including satellites, and any astronauts in space, although a certain few [1] claim that radiation damage to the upper atmosphere would have catastrophic effects as well. At least one scientist has claimed that when the star explodes, "it would be so bright that you would see it during the day, and you could even read a book by its light at night".
- wiki.

Now that's a big one.

This could probably cause a temporary spike in global temperatures.

It might even rival the noon Sun in brightness for seconds, minutes, or hours, if it's on the high end of the mass estimate.

Global Warming?

Feb 27, 2012
I don't think it would be a good thing for life on this planet if this star explodes, because destroying what's left of the ozone, or depleting the magnetosphere would cause significant environmental damage even if the supernova itself isn't immediately catastrophic.

We've go ozone holes the size of a continent. Imagine if an entire hemisphere's worth of ozone was destroyed instantaneously.

Feb 27, 2012
Lurker, the ozone layer has recovered quite a bit since CFC's were banned. Technically, all our CO2 pollution should actually help shield us more...

Feb 27, 2012
This could probably cause a temporary spike in global temperatures.

Why? You can see all sorts of stuff during the day (Venus at dawn or the Moon under certain conditions). This has no measurable impact on global temperatures.
SN 2006gy had a brightness of 14.3 (which is less than the brightness of Pluto in the night sky).
Even if it is much brighter (i.e. you can read a book by its light) we are still talking MUCH less bright than the Moon (and a lot smaller).

Feb 27, 2012

This star is ten times more massive than the crab pulsar's parent star, but only about 15% to 30% farther away, depending on range of margin of error.

Since the energy obvious depends on the type of explosion and how much matter is converted to energy, and how much of it escapes the cloud, then much larger stars should produce much larger explosions, although a higher fraction of the energy will be dissipated or converted to other forms of energy besides gamma, simply because the cloud will be so dense that it won't be transparent.

If it is ten times as energetic explosion, but 30% farther in distance, then we should observe it being at least about 5 or 6 times brighter than the Crab Nebula Supernova (assuming a good estimate on the Crab's distance as a gauge.)

Although it is so big that it may not be the same type of Supernova at all, in which case estimates of the energy release may be futile.

It is in the transition range for mainstream theory of pair instability SN.

Feb 27, 2012
A 2007 study found a supernova outburst by Eta Carina would produce negligible effects as far as Earth is concerned, even if the event was as energetic as SN 2006gy:

Also mentioned in the paper, the likelihood of a blast of gamma rays from Eta Car encountering Earth (in the event a GRB ensues) is negligible, as the axis of rotation of the system is inclined some 40 degrees to our line of sight.

Undoubtedly Eta Carina in outburst will be quite a sight in the southern skies, though as AP mentions, not as bright as the full moon.

Feb 27, 2012

I read the whole paper, and my only criticism at this point is nobody has yet explained what happened to the "missing mass" in the Crab Nebula explosion, although my own hypothesis explains it perfectly, it was ridiculed, so I'll leave that alone.

Point being, when the Crab blew up, it somehow totally annihilated and / or ejected about a third of it's original mass in such a way as that it has never been detected. If it was ejected as particles, there is no expanding shell massive enough to explain it.

Regardless of what happened to the missing mass, it represents an energy component which far exceeds considerations for luminosity or any energies that were converted to kinetic energy or heat in the nebula.

Any unknown massive particles that were ejected would need to be neutral, i.e. perhaps neutrons that somehow escaped during the collapse, etc, in order to evade detection...but the problem with that is you need even more fuel for the explosion to eject that much extra mass.

Feb 27, 2012
In any case, a couple extra solar masses from what is detectable "somehow" escaped the crab pulsar, either as pure photons of some wavelength, or as neutral particles that can't be detected, i.e. perhaps the top layers of the neutron star escaped before it's total collapse, etc.

Now...whatever the case, it's clear that "something" much more energetic than the standard supernova explanations happened.

And the question then becomes how do you account for that behavior and model it in other systems, such as Eta Carina or the Sn 2006gy?

If the Crab's missing mass was ejected as pure neutrons, most of them probably won't be moving very much faster than the atomic matter in the nebula, although there would probably be a curve from maximum to minimum velocities.

If the missing mass was in some form of radiation, photons, or an expanding shell of near-light-speed neutrons, then it's already past use and can't be observed, except possibly through light echos...

Feb 27, 2012
But until someone comes up with a theory to account for the missing mass of the Crab, I don't see how you can discount how serious some of the nearby supernova candidates are, in this case due to being roughly the same distance but ten times the mass.

Whatever the mechanism is, it's clearly more than just cosmic rays and photons involved.

Even if it isn't a threat to the Earth itself, clearly you would not want to be in a space craft or on a space walk on the Moon or Mars when the photons from this hits.

Feb 28, 2012
I read the whole paper, and my only criticism at this point is nobody has yet explained what happened to the "missing mass" in the Crab Nebula explosion, although my own hypothesis explains it perfectly, it was ridiculed -LurkerTard aka Quantum_ConundrumTard

You mean like here:

Feb 28, 2012
For all we know Eta Carinae might have already exploded.

All forms of light and EM Radiation might be hurtling towards us and may reach us tomorrow or the day after or maybe after 7500 years.

Mar 16, 2012
For all we know Eta Carinae might have already exploded.

All forms of light and EM Radiation might be hurtling towards us and may reach us tomorrow or the day after or maybe after 7500 years.

If you feel that this kind of a statement is necessary, then perhaps you need to become a little more familiar with the general definition of 'looking back ino time', every time you see something from a distance. ANYTHING that you see in the sky is an image of what it looked like when the light you are seeing now, left it. It only depends on how long it took it to get here. Even the moon is a bit over a second older (in real terms) than what you are looking at, at that moment. So, yes EC might have already exploded, but we won't know until the light generated by those events reaches us those ca 7500 years later. However, you need to PRESUME that this could be the case, when you read any article that involves astromonical distances. So, such a statement isn't really as sensational..cont

Mar 16, 2012 you are trying to make out.
Here are some links that you might find interesting and educational:
Hop they help, best regards, DH66

Mar 16, 2012
I realize I may have been stating the obvious but I was most definitely not trying to sensationalize this.

Thanks for the links!

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