Explanation: What could shoot out a neutron star like a cannon ball? A supernova. About 10,000 years ago, the supernova that created the nebular remnant CTB 1 not only destroyed a massive star but blasted its newly formed neutron star core -- a pulsar -- out into the Milky Way Galaxy. The pulsar, spinning 8.7 times a second, was discovered using downloadable software Einstein@Home searching through data taken by NASA's orbiting Fermi Gamma-Ray Observatory. Traveling over 1,000 kilometers per second, the pulsar PSR J0002+6216 (J0002 for short) has already left the supernova remnant CTB 1, and is even fast enough to leave our Galaxy. Pictured, the trail of the pulsar is visible extending to the lower left of the supernova remnant. The featured image is a combination of radio images from the VLA and DRAO radio observatories, as well as data archived from NASA's orbiting IRASinfrared observatory. It is well known that supernovas can act as cannons, and even that pulsars can act as cannonballs -- what is not known is how supernovas do it.
Re: APOD: Supernova Cannon Expels Pulsar J0002 (2019 Aug 13)
Posted: Tue Aug 13, 2019 5:48 am
by Ann
I read somewhere that if the supernova explodes asymmetrically, it can send the neutron star or plusar flying.
Of course, just because I read it doesn't make it true.
Ann
Re: APOD: Supernova Cannon Expels Pulsar J0002 (2019 Aug 13)
Posted: Tue Aug 13, 2019 6:47 am
by BDanielMayfield
Ann wrote: ↑Tue Aug 13, 2019 5:48 am
I read somewhere that if the supernova explodes asymmetrically, it can send the neutron star or plusar flying.
Of course, just because I read it doesn't make it true.
Ann
But it often can be if you're selective in what you read. And remember.
I was intending, before seeing Ann's post, just to write two words:
Asymmetrical detonation.
Bruce
Re: APOD: Supernova Cannon Expels Pulsar J0002 (2019 Aug 13)
Posted: Tue Aug 13, 2019 7:02 am
by BDanielMayfield
The stellar core appears to be moving at least twice as fast as the supernova blast front. Amazing.
Re: APOD: Supernova Cannon Expels Pulsar J0002 (2019 Aug 13)
Posted: Tue Aug 13, 2019 8:40 am
by JohnD
There are more things in Heaven and Earth, BDanial Mayfield, than are dreamt of in your philosophy.
"Asymmetric detonation" may explain a cannonball pulsar, but explain asymmetric detonation?
John
Re: APOD: Supernova Cannon Expels Pulsar J0002 (2019 Aug 13)
Posted: Tue Aug 13, 2019 9:35 am
by Ann
JohnD wrote: ↑Tue Aug 13, 2019 8:40 am
There are more things in Heaven and Earth, BDanial Mayfield, than are dreamt of in your philosophy.
"Asymmetric detonation" may explain a cannonball pulsar, but explain asymmetric detonation?
Betelgeuse heading into a wall of dust. Photo: ESA/Herschel.
There might be reasons why a supernova could explode asymmetrically. We know, for example, that red supergiant Betelgeuse is not only colossal in size, but also asymmetrical in shape. Also it is about to crash into a cosmic wall of dust.
Roughly 1000 times the diameter of our Sun and shining 100 000 times more brightly, Betelgeuse’s impressive statistics come with a cost. For this star is likely on its way to a spectacular supernova explosion, having already swelled into a red supergiant and shed a significant fraction of its outer layers.
The new far-infrared view from Herschel shows how the star’s winds are crashing against the surrounding interstellar medium, creating a bow shock as the star moves through space at speeds of around 30 km/s.
A series of broken, dusty arcs ahead of the star’s direction of motion testify to a turbulent history of mass loss.
Closer to the star itself, an inner envelope of material shows a pronounced asymmetric structure. Large convective cells in the star’s outer atmosphere have likely resulted in localised, clumpy ejections of dusty debris at different stages in the past.
And what if the supernova progenitor has a companion? Couldn't a companion star sink into the supergiant's bloated "body" and possibly cause a "sideways" explosion?
Ann
Re: APOD: Supernova Cannon Expels Pulsar J0002 (2019 Aug 13)
Posted: Tue Aug 13, 2019 10:36 am
by neufer
Click to play embedded YouTube video.
Click to play embedded YouTube video.
Re: APOD: Supernova Cannon Expels Pulsar J0002 (2019 Aug 13)
Posted: Tue Aug 13, 2019 12:23 pm
by orin stepanek
Aww! The star went Kaboom! Pretty fast projectile! Fast enough to push it out of the galaxy? Wow!
Re: APOD: Supernova Cannon Expels Pulsar J0002 (2019 Aug 13)
Posted: Tue Aug 13, 2019 1:33 pm
by BDanielMayfield
JohnD wrote: ↑Tue Aug 13, 2019 8:40 am
There are more things in Heaven and Earth, BDanial Mayfield, than are dreamt of in your philosophy.
As is true of ALL human philosophies.
"Asymmetric detonation" may explain a cannonball pulsar, but explain asymmetric detonation?
John
My simple comment was merely offered as an prompt for people to attempt to do exactly that, even as Ann's informative comment has demonstrated. May you have peace doctor.
Bruce
Re: APOD: Supernova Cannon Expels Pulsar J0002 (2019 Aug 13)
Posted: Tue Aug 13, 2019 1:49 pm
by Chris Peterson
JohnD wrote: ↑Tue Aug 13, 2019 8:40 am
There are more things in Heaven and Earth, BDanial Mayfield, than are dreamt of in your philosophy.
"Asymmetric detonation" may explain a cannonball pulsar, but explain asymmetric detonation?
Every supernova is asymmetric, because no progenitor is completely symmetric, in terms of star shape, mass distribution, alignment of magnetic and physical rotation axes, and probably other factors. So really, it's just a question of degree, and given the huge population, not surprising there are outliers.
Re: APOD: Supernova Cannon Expels Pulsar J0002 (2019 Aug 13)
JohnD wrote: ↑Tue Aug 13, 2019 8:40 am
There are more things in Heaven and Earth, BDanial Mayfield, than are dreamt of in your philosophy.
"Asymmetric detonation" may explain a cannonball pulsar, but explain asymmetric detonation?
John
There might be reasons why a supernova could explode asymmetrically. We know, for example, that red supergiant Betelgeuse is not only colossal in size, but also asymmetrical in shape. Also it is about to crash into a cosmic wall of dust.
Roughly 1000 times the diameter of our Sun and shining 100 000 times more brightly, Betelgeuse’s impressive statistics come with a cost. For this star is likely on its way to a spectacular supernova explosion, having already swelled into a red supergiant and shed a significant fraction of its outer layers.
The new far-infrared view from Herschel shows how the star’s winds are crashing against the surrounding interstellar medium, creating a bow shock as the star moves through space at speeds of around 30 km/s.
A series of broken, dusty arcs ahead of the star’s direction of motion testify to a turbulent history of mass loss.
Closer to the star itself, an inner envelope of material shows a pronounced asymmetric structure. Large convective cells in the star’s outer atmosphere have likely resulted in localised, clumpy ejections of dusty debris at different stages in the past.
And what if the supernova progenitor has a companion? Couldn't a companion star sink into the supergiant's bloated "body" and possibly cause a "sideways" explosion?
Ann
Those are excellent ideas Ann. Personally (sorry JohnD), I think you're last question could be on the right track. The asymmetric blobs that turbulently come and go at the surface of stars like Betelgeuse might not be able to have that much of an effect way down deep where the explosion starts.
Bruce
Re: APOD: Supernova Cannon Expels Pulsar J0002 (2019 Aug 13)
Posted: Tue Aug 13, 2019 3:48 pm
by MDB
Had the supernova progenitor been massive enough to produce a black hole, could that have been ejected as well?
Re: APOD: Supernova Cannon Expels Pulsar J0002 (2019 Aug 13)
Posted: Tue Aug 13, 2019 4:20 pm
by Ann
MDB wrote: ↑Tue Aug 13, 2019 3:48 pm
Had the supernova progenitor been massive enough to produce a black hole, could that have been ejected as well?
Apparently black holes can be sent flying by receiving a mighty kick. Hubble has confirmed that a supermassive black hole has been kicked from the center of its galaxy, apparently by gravitational waves.
Astronomers have uncovered a supermassive black hole that has been propelled out of the center of a distant galaxy by what could be the awesome power of gravitational waves.
Though there have been several other suspected, similarly booted black holes elsewhere, none has been confirmed so far. Astronomers think this object, detected by NASA's Hubble Space Telescope, is a very strong case. Weighing more than 1 billion suns, the rogue black hole is the most massive black hole ever detected to have been kicked out of its central home...
Ann
Re: APOD: Supernova Cannon Expels Pulsar J0002 (2019 Aug 13)
Re: APOD: Supernova Cannon Expels Pulsar J0002 (2019 Aug 13)
Posted: Tue Aug 13, 2019 5:27 pm
by MarkBour
Regarding the asymmetry. For any explosion, whether it propels a pulsar or black hole in some direction at great speed. It must propel and equal amount of matter in the opposite direction (okay, actually an opposite delta of momentum).
Re: APOD: Supernova Cannon Expels Pulsar J0002 (2019 Aug 13)
Posted: Tue Aug 13, 2019 5:40 pm
by Chris Peterson
MarkBour wrote: ↑Tue Aug 13, 2019 5:27 pm
Regarding the asymmetry. For any explosion, whether it propels a pulsar or black hole in some direction at great speed. It must propel and equal amount of matter in the opposite direction (okay, actually an opposite delta of momentum).
That's true... although for extremely energetic explosions like this we might need to consider mass-energy equivalence. The momentum need not all come from matter.
Re: APOD: Supernova Cannon Expels Pulsar J0002 (2019 Aug 13)
Posted: Tue Aug 13, 2019 6:32 pm
by JohnD
Earthbound asymmetric detonations are caused by shaped charges, which have a void in the centre of the explosive, and direct a strong pulse out of that void. And Ann points out the asymmetry of Betalgeuse is due to to it meeting an area of greater density in the cosmos, which would lead to a lowering of the density of the nebula around a proto-supernova opposite the dense area. Could this approximate a shaped charge, and lead to the pulsar being ejected in that opposite diection?
BUT, I note the original APOD shows the track of the pulsar, as a glowing streak. A radio- or visual image? And also similar glowing patches on the skin of the nebular left by the exploding star, no seen anywhere else on its perimeter. The pulsar is plouging through some material, and energising it to radiate at some wavelength, and so is the nebula, right behind it. This shows that the above 'shaped charge' theory cannot be the mechanism for the cannon ball effect.
Oh, well, back the drawing board. Next!
JOhn
MarkBour wrote: ↑Tue Aug 13, 2019 5:27 pm
Regarding the asymmetry. For any explosion, whether it propels a pulsar or black hole in some direction at great speed. It must propel and equal amount of matter in the opposite direction (okay, actually an opposite delta of momentum).
That's true... although for extremely energetic explosions like this we might need to consider mass-energy equivalence. The momentum need not all come from matter.
The momentum of the "cannonball" is an easy calculation, with the assumption that the projectile is a neutron star. P=mv, so 1.4 sols x 1127 km/s. Converting to SI units gives 1.4 x 2x10^30kg x 1127x1000m/s = 2.25x10^36kg.m/s or 2.25 Billion Quadrillion Newtons.
MarkBour wrote: ↑Tue Aug 13, 2019 5:27 pm
Regarding the asymmetry. For any explosion, whether it propels a pulsar or black hole in some direction at great speed. It must propel and equal amount of matter in the opposite direction (okay, actually an opposite delta of momentum).
That's true... although for extremely energetic explosions like this we might need to consider mass-energy equivalence. The momentum need not all come from matter.
The momentum of the "cannonball" is an easy calculation, with the assumption that the projectile is a neutron star. P=mv, so 1.4 sols x 1127 km/s. Converting to SI units gives 1.4 x 2x10^30kg x 1127x1000m/s = 2.25x10^36kg.m/s or 2.25 Billion Quadrillion Newtons.
Except... kg⋅m/s (correct units for momentum) are not newtons (a unit of force, kg⋅m/s2). And to be a little picky, "newton" is not capitalized as a unit, although "N" is.
That's true... although for extremely energetic explosions like this we might need to consider mass-energy equivalence. The momentum need not all come from matter.
The momentum of the "cannonball" is an easy calculation, with the assumption that the projectile is a neutron star. P=mv, so 1.4 sols x 1127 km/s. Converting to SI units gives 1.4 x 2x10^30kg x 1127x1000m/s = 2.25x10^36kg.m/s or 2.25 Billion Quadrillion Newtons.
Except... kg⋅m/s (correct units for momentum) are not newtons (a unit of force, kg⋅m/s2). And to be a little picky, "newton" is not capitalized as a unit, although "N" is.
I sit corrected, which was needed here, so thanks. So then to compute the violence of this canon shot we also need to know the duration (time) it took to accelerate the stellar remnant. How long might this have taken?
The momentum of the "cannonball" is an easy calculation, with the assumption that the projectile is a neutron star. P=mv, so 1.4 sols x 1127 km/s. Converting to SI units gives 1.4 x 2x10^30kg x 1127x1000m/s = 2.25x10^36kg.m/s or 2.25 Billion Quadrillion Newtons.
Except... kg⋅m/s (correct units for momentum) are not newtons (a unit of force, kg⋅m/s2). And to be a little picky, "newton" is not capitalized as a unit, although "N" is.
I sit corrected, which was needed here, so thanks. So then to compute the violence of this canon shot we also need to know the duration (time) it took to accelerate the stellar remnant. How long might this have taken?
Well, if it's a core collapse SN, most of the energy is released in the form of neutrinos, perhaps 1046 joules (with maybe 1% of that released in the kinetic energy of ejecta, and a tiny fraction as electromagnetic radiation). Most of this energy is released over a few hundred seconds. So really, just the tiniest imbalance of radiation could result in huge momentum imbalances of ordinary matter.
Chris Peterson wrote: ↑Tue Aug 13, 2019 5:40 pm
That's true... although for extremely energetic explosions like this we might need to consider mass-energy equivalence. The momentum need not all come from matter.
The momentum of the "cannonball" is an easy calculation, with the assumption that the projectile is a neutron star. P=mv, so 1.4 sols x 1127 km/s. Converting to SI units gives 1.4 x 2x10^30kg x 1127x1000m/s = 2.25x10^36kg.m/s or 2.25 Billion Quadrillion Newtons.
Except... kg⋅m/s (correct units for momentum) are not newtons (a unit of force, kg⋅m/s2).
Also...
1) You use the non-English "long scale" for Billion Quadrillion.
2) You forgot to multiply by the "1.4" :
1.4 x 2x1030kg x 1127x1000 m/s = 3.16x1036kg.m/s = 3.16 million million yottanewton seconds.
https://en.wikipedia.org/wiki/Long_and_short_scales wrote:
Long scale: Every new term greater than million is one million times as large as the previous term. Thus, billion means a million millions (1012), trillion means a million billions (1018), and so on. Thus, an n-illion equals 106n.
Short scale: Every new term greater than million is one thousand times as large as the previous term. Thus, billion means a thousand millions (109), trillion means a thousand billions (1012), and so on. Thus, an n-illion equals 103n + 3.
The short scale is now used in most English-speaking and Arabic-speaking countries, in Brazil and several other countries. For most of the 19th and 20th centuries, the United Kingdom largely used the long scale, whereas the United States used the short scale, so that the two systems were often referred to as British and American in the English language. After several decades of increasing informal British usage of the short scale, in 1974 the government of the UK adopted it, and it is used for all official purposes.
Countries where the long scale is currently used include most countries in continental Europe and most that are French-speaking, Spanish-speaking (except Spanish-speakers born into an English-speaking culture, e.g. Puerto Rico, because of its influence from English-speaking United States) and Portuguese-speaking countries, except Brazil.
To avoid confusion resulting from the coexistence of short and long term in any language, the International System of Units (SI) recommends using the metric prefix to indicate orders of magnitude. As opposed to words like billion and million, metric prefixes keep the same meaning regardless of the country and the language.>>
<<In classical mechanics, impulse (symbolized by J or Imp) is the integral of a force, F, over the time interval, t, for which it acts. Since force is a vector quantity, impulse is also a vector in the same direction. Impulse applied to an object produces an equivalent vector change in its linear momentum, also in the same direction. The SI unit of impulse is the newton second (N⋅s), and the dimensionally equivalent unit of momentum is the kilogram meter per second (kg⋅m/s). The corresponding English engineering units are the pound-second (lbf⋅s) and the slug-foot per second (slug⋅ft/s).>>
<<Slug, or land slug, is a common name for any apparently shell-less terrestrial gastropod mollusc. Gastropods typically have a ventral foot, which gives them their name (Greek gaster, stomach, and poda, feet).>>
Re: APOD: Supernova Cannon Expels Pulsar J0002 (2019 Aug 13)
MarkBour wrote: ↑Tue Aug 13, 2019 5:27 pm
Regarding the asymmetry. For any explosion, whether it propels a pulsar or black hole in some direction at great speed. It must propel and equal amount of matter in the opposite direction (okay, actually an opposite delta of momentum).
That's true... although for extremely energetic explosions like this we might need to consider mass-energy equivalence. The momentum need not all come from matter.
And thanks also to Mark for taking the discussion in a Newtonian direction. Nice application of his second law of motion.
I was wondering how much of the opposing momentum might be being carried by the expanding SN remnant. For one thing, it probably out masses the stellar remnant by several times. With reference to the SN progenitor's location at the time of detonation, the whole bubble might be moving in the exact opposite direction of the "canonball", but at a much lower velocity due to its larger mass and to the Einsteinian factor Chris mentioned.
BDanielMayfield wrote: ↑Tue Aug 13, 2019 6:58 pm
The momentum of the "cannonball" is an easy calculation, with the assumption that the projectile is a neutron star. P=mv, so 1.4 sols x 1127 km/s. Converting to SI units gives 1.4 x 2x10^30kg x 1127x1000m/s = 2.25x10^36kg.m/s or 2.25 Billion Quadrillion Newtons.
Except... kg⋅m/s (correct units for momentum) are not newtons (a unit of force, kg⋅m/s2).
Also...
1) You use the non-English "long scale" for Billion Quadrillion.
2) You forgot to multiply by the "1.4" :
1.4 x 2x1030kg x 1127x1000 m/s = 3.16x1036kg.m/s = 3.16 million million yottanewton seconds.
https://en.wikipedia.org/wiki/Long_and_short_scales wrote:
Long scale: Every new term greater than million is one million times as large as the previous term. Thus, billion means a million millions (1012), trillion means a million billions (1018), and so on. Thus, an n-illion equals 106n.
Short scale: Every new term greater than million is one thousand times as large as the previous term. Thus, billion means a thousand millions (109), trillion means a thousand billions (1012), and so on. Thus, an n-illion equals 103n + 3.
The short scale is now used in most English-speaking and Arabic-speaking countries, in Brazil and several other countries. For most of the 19th and 20th centuries, the United Kingdom largely used the long scale, whereas the United States used the short scale, so that the two systems were often referred to as British and American in the English language. After several decades of increasing informal British usage of the short scale, in 1974 the government of the UK adopted it, and it is used for all official purposes.
Countries where the long scale is currently used include most countries in continental Europe and most that are French-speaking, Spanish-speaking (except Spanish-speakers born into an English-speaking culture, e.g. Puerto Rico, because of its influence from English-speaking United States) and Portuguese-speaking countries, except Brazil.
To avoid confusion resulting from the coexistence of short and long term in any language, the International System of Units (SI) recommends using the metric prefix to indicate orders of magnitude. As opposed to words like billion and million, metric prefixes keep the same meaning regardless of the country and the language.>>
<<In classical mechanics, impulse (symbolized by J or Imp) is the integral of a force, F, over the time interval, t, for which it acts. Since force is a vector quantity, impulse is also a vector in the same direction. Impulse applied to an object produces an equivalent vector change in its linear momentum, also in the same direction. The SI unit of impulse is the newton second (N⋅s), and the dimensionally equivalent unit of momentum is the kilogram meter per second (kg⋅m/s). The corresponding English engineering units are the pound-second (lbf⋅s) and the slug-foot per second (slug⋅ft/s).>>
<<Slug, or land slug, is a common name for any apparently shell-less terrestrial gastropod mollusc. Gastropods typically have a ventral foot, which gives them their name (Greek gaster, stomach, and poda, feet).>>
And thank you also. Even tho I err, in the attempt I learn.
Re: APOD: Supernova Cannon Expels Pulsar J0002 (2019 Aug 13)
Posted: Tue Aug 13, 2019 8:42 pm
by BDanielMayfield
To sum up, with the above corrections applied, the blast gave the cannonball so much of a kick that it is moving with 3.16x10^36kg.m/s of momentum.
Translation into common language; this stellar core got it's ass kicked hard. Real hard. So hard that it must leave the galaxy.
Supernova Cannon Expels Pulsar J0002
Pretty fast projectile! Fast enough to push it out of the galaxy? Wow!
