Cannonball star blasts away from the scene of the crime

By Phil Plait | June 29, 2012 9:49 am

When I picture an exploding star in my head — which I do unsurprisingly often — the imaginary mental detonation I picture is symmetric. That is, it expands like a sphere, getting bigger in all directions equally.

Supernovae are actually not like that though. Stars are messy affairs, and when massive ones explode they tend to have internal factors that distort that nice, smooth expansion. One big factor is that the actual point of explosion is off-center in the star, not at its exact heart. That can create a massively asymmetric explosion, blasting vast amounts of material and energy off to one side.

Mind you, the core itself in such a star still collapses to become a super-dense neutron star (or a black hole), but the sideways nature of the explosion can give a kick to the leftover ball of neutrons. Quite a kick. In fact, the energies are so titanic that an off-center supernova explosion can blast the neutron star in the other direction, screaming away from the explosion site like a shell out of the muzzle of a battleship gun.

And now astronomers may have found the most extreme example of this: what looks to be just such a neutron star barreling away from a supernova at high speed:

[Click to Chandrasekharenate.]

This image is a combination of observations from the XMM-Newton and Chandra X-ray observatories, the Digitized Sky Survey, and the 2MASS infrared survey. It shows the supernova remnant SNR MSH 11-16A, located about 30,000 light years away. The purple glow is from X-rays emitted by the gas superheated to millions of degrees by the exposion.

But look off to the right. See that comet-looking thing? I’ve put a close up of it here. You can see a dot at the head of the "comet": astronomers think that might be the runaway neutron star from the explosion that created SNR MSH 11-16A! It’s hard to know for sure, but a lot of things add up to make me think they’re right.

The most obvious is that tail of gas pointing right back to the center of the supernova gas cloud. A hot, young neutron star blows out a high-energy wind of subatomic particles called a pulsar wind, and that pushes against gas floating out in space. As a runaway neutron star blasts through space, it would leave a glowing trail like that. The X-rays appear to be coming from a single, tiny point, just what you’d expect for a neutron star, and observations using optical and infrared don’t see it; again, just what you’d expect since neutron stars are tiny and don’t glow visibly. They’re brightest in X-rays due to their phenomenally strong magnetic fields whipping particles around at high energies.

The fainter tail to the side is something of a mystery, though. Apparently things like this have been seen before, but it’s not clear what’s causing it.

Knowing the distance to the supernova remnant we can get its size, which, together with its expansion rate, tells us that it’s something like 15,000 years old. If that dot is the ejected neutron star, it’s screaming away from the explosion site at a mind-numbing 10 million kilometers per hour (6 million mph) — fast enough to cross the entire United State in two seconds flat! Yegads.

Other runaway neutron stars have been seen moving away from supernovae at high speeds, but none this fast. Again, this has not been confirmed to be the neutron star in question, but if it is, it handily holds the speed record for such an event. Mind you, this star probably has about the mass of the Sun: over an octillion tons!

Can I get another "yegads" from the congregation?

Images like this show me that my mental images of some phenomena need to be updated. We like to simplify in our heads, and that’s fine if it helps us get a grip, a basic understanding, of a complex event. But we have to remember that the Universe is weird and complex and sometimes gleefully bent on crushing our preconceptions. That might make some people uncomfortable, but it fills me with joy. Who wants a boring Universe where we easily understand everything?

Weirdness is way more fun.

Image credit: X-ray: NASA/CXC/UC Berkeley/J.Tomsick et al & ESA/XMM-Newton, Optical: DSS; IR: 2MASS/UMass/IPAC-Caltech/NASA/NSF

Related Posts:

- Rampaging cannonball star is rampaging
- Runaway star
- The Crab is still crabby
- Shocking star is shocking. Shocking, I say!

CATEGORIZED UNDER: Astronomy, Pretty pictures, Top Post

Comments (32)

  1. Thanny

    Is there perhaps a massive star at the center of that arc, the wind of which gas from the supernova is piling up against?

  2. Has anyone ever visualised and calculated through what would happen if a neutron star with this speed would smash into the earth? Would it just fly straight through the planet in some 4,5 seconds (obviously leaving massive devastation at entry and exit, but not obliterating the planet) or would its gravity be so strong that the whole planet would essentially be sucked on and become part of the neutron star during the passage. I actually think it will be the first. I guess that parts of the earth that are more than a few dozen kilometers away from the ‘tunnel’ will mostly stay electrostatically bound to the planet, not succumbing to the force of gravity from the neutron star (which won’t last for more than a fraction of a second anyway). But this is just my gut feeling, I didn’t do any calculations.

  3. Timmy

    You seem to have a thing for kilometers. If the US ever officially changes over to the metric system I’m moving to Canada!

  4. Gaebolga

    I’m stuck on the phrase “hot, young neutron star”…sounds like something an aging main sequence star might try to strike up a relationship with.

    It would be an odd binary system, though….

  5. Jules: I used WolframAlpha to do some quick math. 10^7 kph is about .0093C, so no relativistic effects. Kinetic energy is a straight 1/2 m*(v^2) which equals 7.716*10^42 Joules.

    That compares to about 1/13 the energy of a typical supernova.

    Now I have to remember my equations for an (in)-elastic collision. But I imagine this would be more like a large bullet hitting a watermelon.

    Anyone else with thoughts?

  6. Chris

    @2 Jules

    You have to realize the neutron star is more massive than our own Sun, so if that is plowing through the solar system it is going to seriously perturb the planets’ orbits. Most of the time it’d probably slingshot the Earth into a new orbit or out of the Solar System. If it was a direct collision, the Earth would probably get torn to shreds by tidal forces (spaghettification is not just for black holes) and the pieces would fall to the surface, although some might get flung away. It would not be a nice hole through the Earth. Either way, majorly screwed.

    @4 Gaebolga

    Ironically a “hot young neutron star” would not be robbing the cradle, but robbing the grave!

  7. Timmy – Canada uses the metric system. So, good luck with that. When i was a kid, the US auto industry seemed hell bent on avoiding the metric system. It’s now metric. I overheard two engineers talking about 15 inch wheels. Once they were talking about real measurements, it was all metric. Apparently “15 inch wheels” is used as a marketing name. Parts drawings are all metric. And, the auto industry is metric for the same reason it used to avoid metric. It’s cheaper.

    Runaway neutron stars are fast, but they’re unlikely to be used for transportation any time soon.

  8. Will that leave the galaxy?

  9. Ians

    Timmy, the USA is already a metric country and has been for many many years : “Under the Mendenhall Order in 1893, metric standards, developed through international cooperation under the auspices of BIPM, were adopted as the fundamental standards for length and mass in the United States. The U.S. customary units such as the foot and pound have been defined in relation to metric units ever since.”


  10. Chris

    @8 Lab Lemming

    A quick search has the escape velocity from our galaxy as ~500 km/s. 10 million kph is ~2800 km/s. So this neutron star has more than it needs and it’s probably going to sail off into the void.

  11. scgvlmike

    “United States per second” should be a new ISO unit.

  12. Artor

    @ Everyone responding to Timmy- I think he was making a joke on all the teabaggers who are so upset that the Supremes upheld “socialized medicine,” that they’re moving to Canada, ignorant of the fact that Canada already has REAL socialized medicine.

    @Jules Stoop- Here’s what I would imagine, putting aside the slingshot effects such a body moving through the solar system might have. The neutron star plows through the planet like a bullet through a soap bubble, not slowing down in any measurable amount. The planet retains a spherical shape, sans the 20-mile wide hole cored through the middle. However, everything within 1000 miles or so of that hole experiences a fusion blast that dwarfs anything ever seen in this solar system as several trillion tons of earth are converted to neutrons on impact. The resulting x, gamma and cosmic rays sterilize any trace of life in the solar system, and the hot, lifeless carcass of the planet experiences several millennia of earthquakes as the mantle oozes into the empty shaft left behind. What do you say Phil? Am I far off?

  13. Chris

    Those talking about neutron star collisions. The Roche Limit is what decides how close a body can get before its own self gravity is overcome and the body is being torn apart by tidal forces. Probably what caused the Rings of Saturn. The Roche Limit for the Earth around the Sun (and similarly for the neutron star) is between a half and one million km. So this neutron star would take about 6-12 minutes to cross that distance. Assuming the Earth is still in once piece when the neutron star reaches the center of the Earth, we’d feel ~800,000 g’s of acceleration at the surface. For comparison, a Magnitude 9 earthquake has a peak ground acceleration of ~2 g. The big question here is how fast would the Earth respond to such massive gravity. I don’t know, but it wouldn’t be pretty.

  14. Jon

    Great picture and description, thank you! It’d be very interesting to see something like this interacting with other stars of various types, black holes, nebula, etc with that velocity.

    I think just like Shoemaker-Levy 9 sort of woke us up that we need to pay attention to comets and asteroids seriously in order to survive as a species, seeing a planetary system ripped apart by something like this plowing into it could hopefully convince a few more people that our priorities are a bit off at the moment.

  15. Stephen Olander-Waters

    What are the odds that the “purple” cloud off the side is a polar jet (or being illuminated by a polar jet)?

  16. rob
  17. Thanks people :) I was indeed aware of the mass of the neutron star, so initially I was also thinking more or less along the lines of Artor’s reasoning. But you can see I didn’t do the math, as Chris points out that at least 6 minutes before contact, stuff not tied to the earth would already start falling towards the neutron star rather than towards the center of the Earth. By the time it is some 10 seconds away, the acceleration caused by its gravitational field starts to run into the tens of thousands of g’s. I’d think that’s more than enough to turn our planet inside out, so to say. Maybe not all of our planet will gain enough speed to be sucked-in and become ultra-dense neutron-matter, but what’s left after the passage – just because of friction between parts of matter which were once part of our planet – will essentially be little more than a cloud of hot and vaporized rock/metal. Some of it might re-coalesce into a new solid body, but most of what doesn’t end up as part of the neutron star, will probably be slingshot away. Complete obliteration!

  18. Joseph G

    Speak it, Brother Phil!

  19. bruce

    So with that combination of speed and distance from us, how long will we wait before a second photo will give us an indication of speed?

    Oh, and yegads.

  20. Chris

    @20 bruce
    10 million km/hour for one year is 0.00927 light years. So the angle it’ll move in the sky is
    0.00927/30000 = 3 x 10^-7 radians/year
    Do a little converting into arc seconds and we get
    0.064 arcseconds per year.

    Chandra has an angular resolution of 0.5 arc seconds, so about 10 years.

  21. JB of Brisbane

    “It’s Praxis, sir…”

    @Timmy – good Poe, man.

  22. kat wagner

    Where in the Cosmos
    IGR J11014 was the focus of today’s “Where in the Cosmos” photo quiz on the Cosmic Log Facebook page, and I swear it took less than a minute for Turkish astronomer Arif Solmaz to figure out that the green blob in the picture was a pulsar. In recognition of his quick wits (and quick typing fingers), I’m sending him a pair of 3-D glasses, provided courtesy of the WorldWide Telescope team, as well as a signed 3-D picture of yours truly. Kathi Wagner wasn’t far behind, thanks to the fact that she had read about IGR J11014 on Phil Plait’s Bad Astronomy blog — and because any friend of Phil’s is a friend of mine, she’ll be getting some 3-D glasses as well.

    How ’bout that? From Alan Boyle at Cosmic Log, MSNBC. Now I can’t say I never won anything.

  23. Messier Tidy Upper

    Can I get another “yegads” from the congregation?

    Yegads! :-)

    If that dot is the ejected neutron star, it’s screaming away from the explosion site at a mind-numbing 10 million kilometers per hour (6 million mph) — fast enough to cross the entire United State in two seconds flat! .. this star probably has about the mass of the Sun: over an octillion tons!

    All crammed down into about the size of a city right? Do we know how many kilometers diameter this Neutron Star Supernovae-Slingshot-Stone is?

    Yegads indeed. 8)

    @kat wagner – June 29th, 2012 at 8:53 pm : Congratulations. :-)

  24. Svlad Cjelli

    And what happens when two of these meet?

  25. Wzrd1

    @Stephen Olander-Waters, you just gave me a headache thinking about the math involved in such a thing!
    But, it’s a way cool induced headache. :)

    @Jules Stoop, figure about 6 minutes before the Earth begins to disintegrate at best. I didn’t bother doing the math, but the nullified gravitation on the facing side is enough to approximate the effects.
    The Earth would be shredded by tidal effects quite quickly.
    As in, not getting WTF out and only getting “Wha-” before losing the planet under one’s feet, then, quickly losing one’s body.
    IF it’s on a collision course.

  26. bruce

    Thanks, Chris, I’ll wait.

    The numbers were way too big for me. – yegads.

  27. phdnk

    @ Jules Stoop
    Fusion yield estimation.

    I think, if a neutron star plowed through the Earth, it would cause fusion all the material upon contact. Let’s estimate the thermonuclear yield of such an event: all the mantle that would have been on the star’s path (R=10km) would have been fused to iron-56. It is two cylinders of rock (before and after the core) with combined mass ~10^19 kg. If we take into account the chemical composition of that rock and corresponding binding energies of the nuclei, we will come with the yield of ~3.7*10^60 eV.

    Wolfram Alpha says, that the Earth’s binding energy is 1.4*10^51 eV.
    So, the event would have produced more than enough of heat to disintegrate our planet, albeit with a delay.

    There will also be an impulse transfer via gravitation.

  28. Bob

    Should this be called a shooting star?

  29. @Stephen Olander-Wlaters. Yeah, it certainly seems associated with the neutron star, but still it’a hard to see the purple line being a jet from the high speed ejected star itself. The jet is just too straight. The material in jets is being channeled off the object itself, which is moving very rapidly away from the explosion event. From almost any line of sight, this should create a curved line away from the star.

    Everything would have to line up very precisely just for us to see it as a straight line from where we sit on earth. Also i notice that the “jet” also nearly at a right angle from the path of the neutron star. It flew out of an asymmetrical explosion, how is it managing such low levels of distortion? Even jets from relatively still neutron stars have a slightly mangled look to them. this one is traveling at record speeds!

    Also shouldn’t the jet curve or distort since the matter in the jet is encountering resistance in the interstellar medium? Its at a lower density and obviously doesn’t have the mass of the neutron star. this should make it interact more easily with the medium, and we should be able to see that. a lot of jets balloon out at the end because of this. This jet just plows through like a giant pole? That would be odd. If anything its curving forward instead of backward, don’t you think?

    And it looks like the total length of the jet (if thats what it is) is about one third of the length that the entire neutron star has traveled away from the center of the remnant’s nebula. Thats significant because it means the matter at the end of the jet has traveled further. how is the jet matter at the end keeping up the high speed?

    Also i think if it were a jet, that would make this an image of the more rare one sided jet, making an already extraordinary find that much more unlikely.

    but clearly, it seems associated with the neutron star. sure maybe its something else a lot closer or further, or another object is generating a one sided jet that happen to overlap the image of the one flying away from the supernova, but that seem even more silly.

    amazing image, i really wonder what that thing is.


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