APOD: Filaments of the Vela Supernova Remnant (2013 Oct 01)

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APOD: Filaments of the Vela Supernova Remnant (2013 Oct 01)

Post by APOD Robot » Tue Oct 01, 2013 4:05 am

Image Filaments of the Vela Supernova Remnant

Explanation: The explosion is over but the consequences continue. About eleven thousand years ago a star in the constellation of Vela could be seen to explode, creating a strange point of light briefly visible to humans living near the beginning of recorded history. The outer layers of the star crashed into the interstellar medium, driving a shock wave that is still visible today. A roughly spherical, expanding shock wave is visible in X-rays. The above image captures some of that filamentary and gigantic shock in visible light. As gas flies away from the detonated star, it decays and reacts with the interstellar medium, producing light in many different colors and energy bands. Remaining at the center of the Vela Supernova Remnant is a pulsar, a star as dense as nuclear matter that rotates completely around more than ten times in a single second.

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Re: APOD: Filaments of the Vela Supernova Remnant (2013 Oct

Post by Boomer12k » Tue Oct 01, 2013 6:50 am

Always amazes me...."Ten Times a Second"....a Star.....Amazing!!!!!
Is that Conservation of Angular Momentum?

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Re: APOD: Filaments of the Vela Supernova Remnant (2013 Oct

Post by Markus Schwarz » Tue Oct 01, 2013 7:37 am

Boomer12k wrote:Is that Conservation of Angular Momentum?
It is. The process is similar to that of a spinning ice skater who pulls in her arms to increase her spin. During a supernova the outer region of the star is shaken off and the inner region contracts, which leads to an increase in angular speed of the neutron star.

If you have an office chair, you can do the following experiment: With your arms outstretched, push with your feed so that you start rotating. Now pull in your arms and notice an increase in your angular velocity. The speed decreases once you stretch out your arms again.

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Re: APOD: Filaments of the Vela Supernova Remnant (2013 Oct

Post by Ann » Tue Oct 01, 2013 2:46 pm

It's a beautiful image, but I'm not sure of the orientation of it. Is north up?

A fascinating aspect of the general region of the Vela supernova remnant is that we can see many young and very bright stars in this part of the sky. There are several stars here which have extremely tiny Hipparcos parallaxes and appear to very far away and very very bright.

To put it differently, I get the impression, by looking at the stars in the vicinity, that the Vela supernova progenitor may also have been a very massive star, and that it was a core-collapse supernova.

Of course I don't know that this is the case, but that is the impression I get from looking at several of the stars that appear to be tangled in the filaments of the Vela supernova remnant.

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Re: APOD: Filaments of the Vela Supernova Remnant (2013 Oct

Post by Chris Peterson » Tue Oct 01, 2013 2:54 pm

As gas flies away from the detonated star, it decays and reacts with the interstellar medium, producing light in many different colors and energy bands.
That is an oddly worded and rather confusing statement.

I think something like this is intended: As atoms fly away from the detonated star, some undergo radioactive decay into other elements, which interact with the interstellar medium to produce light of many different colors.
Chris

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Re: APOD: Filaments of the Vela Supernova Remnant (2013 Oct

Post by Ann » Tue Oct 01, 2013 3:56 pm

I guess Vela X-1 has nothing to do with the Vela supernova remnant. Still, Vela X-1 is a binary star, whose components are a massive normal B-type supergiant and a neutron star. To the best of my understanding, the neutron star must be a supernova remnant. The Vela X-1 system is speeding through space, creating an elegant bow shock in front of it.

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Re: APOD: Filaments of the Vela Supernova Remnant (2013 Oct

Post by Andrew Garland » Tue Oct 01, 2013 6:59 pm

The explanation at the link to the x-ray image says that image covers 100 times the angular area of the full moon. So, it is roughly 10 times the diameter.

It would be interestingto see an overlay of what the sky would look like if many of the more interesting nebula, galaxies, and remnants were presented as if they were visible to the eye. It seems that the sky would be filled with large images of moon diameter or larger.

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Re: APOD: Filaments of the Vela Supernova Remnant (2013 Oct

Post by LocalColor » Tue Oct 01, 2013 9:40 pm

Got here via the mirror link - thank you for keeping it going APOD!

Two "wows" and six thumbs up for today's image. Stunning!

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Re: APOD: Filaments of the Vela Supernova Remnant (2013 Oct

Post by neufer » Wed Oct 02, 2013 2:47 am

Boomer12k wrote:
Always amazes me...."Ten Times a Second"....a Star.....Amazing!!!!!
http://en.wikipedia.org/wiki/Millisecond_pulsar wrote:
<<A millisecond pulsar (MSP) is a pulsar with a rotational period in the range of about 1-10 milliseconds. Millisecond pulsars have been detected in the radio, X-ray, and gamma ray portions of the electromagnetic spectrum. The origin of millisecond pulsars is still unknown. The leading theory is that they begin life as longer period pulsars but are spun up or "recycled" through accretion. For this reason, millisecond pulsars are sometimes called recycled pulsars.

Millisecond pulsars are thought to be related to low-mass X-ray binary systems. It is thought that the X-rays in these systems are emitted by the accretion disk of a neutron star produced by the outer layers of a companion star that has overflowed its Roche lobe. The transfer of angular momentum from this accretion event can theoretically increase the rotation rate of the pulsar to hundreds of times a second, as is observed in millisecond pulsars.

Many millisecond pulsars are found in globular clusters. This is consistent with the spin-up theory of their formation, as the extremely high stellar density of these clusters implies a much higher likelihood of a pulsar having (or capturing) a giant companion star. Currently there are approximately 130 millisecond pulsars known in globular clusters. The globular cluster Terzan 5 alone contains 33 of these, followed by 47 Tucanae with 22 and M28 and M15 with 8 pulsars each.

Millisecond pulsars, which can be timed with high precision, are better clocks than the best atomic clocks. This also makes them very sensitive probes of their environments. For example, anything placed in orbit around them causes periodic Doppler shifts in their pulses' arrival times on Earth, which can then be analyzed to reveal the presence of the companion and, with enough data, provide precise measurements of the orbit and the object's mass. The technique is so sensitive that even objects as small as asteroids can be detected if they happen to orbit a millisecond pulsar. The first confirmed exoplanets discovered several years before the first detections of exoplanets around “normal” solar-like stars, were found in orbit around a millisecond pulsar, PSR B1257+12. These planets remained for many years the only Earth-mass objects known outside our solar system. And one of them, with an even smaller mass, comparable to that of our Moon, is still today the smallest-mass object known beyond the solar system.

The first millisecond pulsar, PSR B1937+21, was discovered in 1982 by Backer et al. Spinning roughly 641 times a second, it remains the second fastest-spinning millisecond pulsar of the approximately 200 that have been discovered. Pulsar PSR J1748-2446ad, discovered in 2005, is, as of 2012, the fastest-spinning pulsar currently known, spinning 716 times a second.

Current theories of neutron star structure and evolution predict that pulsars would break apart if they spun at a rate of ~1500 rotations per second or more, and that at a rate of above about 1000 rotations per second they would lose energy by gravitational radiation faster than the accretion process would speed them up.

However, in early 2007 data from the Rossi X-ray Timing Explorer and INTEGRAL spacecraft discovered a neutron star XTE J1739-285 rotating at 1122 Hz. The result is not statistically significant, with a significance level of only 3 sigma. Therefore, while it is an interesting candidate for further observations, current results are inconclusive. Still, it is believed that gravitational radiation plays a role in slowing the rate of rotation. Furthermore, one X-ray pulsar that spins at 599 revolutions per second, IGR J00291+5934, is a prime candidate for helping detect such waves in the future (most such X-ray pulsars only spin at around 300 rotations per second).>>
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Re: APOD: Filaments of the Vela Supernova Remnant (2013 Oct

Post by Nitpicker » Wed Oct 02, 2013 3:34 am

The Jade Scope Observatory, in the dark boondocks of New South Wales and run remotely from Hong Kong, gives me a serious case of green envy, but I am nowhere near New Brunswick, so not related to the APOD from the day before.

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Re: APOD: Filaments of the Vela Supernova Remnant (2013 Oct

Post by ta152h0 » Sun Oct 13, 2013 11:21 pm

How come I cannot observe APOD beyong the Oct 1 page ? Something I said ????
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Re: APOD: Filaments of the Vela Supernova Remnant (2013 Oct

Post by geckzilla » Mon Oct 14, 2013 12:50 am

The site is down along with the US government shutdown. Anything you are viewing is either cache or a mirror.
Just call me "geck" because "zilla" is like a last name.