APOD: The Structured Tails of Comet NEOWISE (2020 Jul 22)

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APOD Robot
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APOD: The Structured Tails of Comet NEOWISE (2020 Jul 22)

Post by APOD Robot » Wed Jul 22, 2020 4:07 am

Image The Structured Tails of Comet NEOWISE

Explanation: What is creating the structure in Comet NEOWISE's tails? Of the two tails evident, the blue ion tail on the left points directly away from the Sun and is pushed out by the flowing and charged solar wind. Structure in the ion tail comes from different rates of expelled blue-glowing ions from the comet's nucleus, as well as the always complex and continually changing structure of our Sun's wind. Most unusual for Comet C/2020 F3 (NEOWISE), though, is the wavy structure of its dust tail. This dust tail is pushed out by sunlight, but curves as heavier dust particles are better able to resist this light pressure and continue along a solar orbit. Comet NEOWISE's impressive dust-tail striations are not fully understood, as yet, but likely related to rotating streams of sun-reflecting grit liberated by ice melting on its 5-kilometer wide nucleus. The featured 40-image conglomerate, digitally enhanced, was captured three days ago through the dark skies of the Gobi Desert in Inner Mongolia, China. Comet NEOWISE will make it closest pass to the Earth tomorrow as it moves out from the Sun. The comet, already fading but still visible to the unaided eye, should fade more rapidly as it recedes from the Earth.

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RocketRon

Re: APOD: The Structured Tails of Comet NEOWISE (2020 Jul 22)

Post by RocketRon » Wed Jul 22, 2020 6:08 am

That is a truly spectacular image.
Thankyou.

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orin stepanek
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Re: APOD: The Structured Tails of Comet NEOWISE (2020 Jul 22)

Post by orin stepanek » Wed Jul 22, 2020 12:03 pm

Neowise_Lin_960.jpg

Lovely to look at; delightful to behold! You cannot
stop it; and it's very old! :mrgreen:
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Orin

Smile today; tomorrow's another day!

JRock

Re: APOD: The Structured Tails of Comet NEOWISE (2020 Jul 22)

Post by JRock » Wed Jul 22, 2020 1:54 pm

Is it possible that the rotation of the nucleus contributes to the tail striations? Material may be ejected tangentially to the solar wind at some times and parallel to it as others. I am certainly not deeply learned in comet structure and behavior but the thought jumped out at me.

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neufer
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Comet Klinkenberg-Chéseaux

Post by neufer » Wed Jul 22, 2020 2:48 pm

JRock wrote:
Wed Jul 22, 2020 1:54 pm

Is it possible that the rotation of the nucleus contributes to the tail striations? Material may be ejected tangentially to the solar wind at some times and parallel to it as others. I am certainly not deeply learned in comet structure and behavior but the thought jumped out at me.
http://en.wikipedia.org/wiki/C/1743_X1 wrote:
<<Charles Messier (26 June 1730 – 12 April 1817) [first took an] interest in astronomy by the appearance of the spectacular, great six-tailed comet in 1744 and by an annular solar eclipse visible from his hometown on 25 July 1748.

The Great Comet of 1744, also known as Comet Klinkenberg-Chéseaux, was a spectacular comet that was observed during 1743 and 1744. It became visible with the naked eye for several months in 1744 and displayed dramatic and unusual effects in the sky. Its absolute magnitude — or intrinsic brightness — of 0.5 was the sixth highest in recorded history. By February 18, 1744, it reportedly was as bright as the planet Venus (with an apparent magnitude of -4.6) and at this time displayed a double tail.

The comet reached perihelion about March 1, 1744, when it was 0.2 astronomical units from the sun. At about this time it was bright enough to be observed in daylight with the naked eye. As it moved away from perihelion, a spectacular tail developed — extending well above the horizon while the comet's head remained invisible due to the morning twilight. In early March 1744, Chéseaux and several other observers reported an extremely unusual phenomenon — a 'fan' of six separate tails rose above the horizon. It has been suggested that the 'fan' of tails was generated by as many as three active sources on the cometary nucleus, exposed in turn to solar radiation as the nucleus rotated. It also has been proposed that the tail phenomenon was a very prominent example of the "dust striae" seen in the tails of some comets, such as Comet West and C/2006 P1 (McNaught).

The Great Comet of 1744 also was noted in Chinese astronomical records. Researchers have found that some of their observations describe audible sounds associated with the comet, which may, if true, have resulted from the interaction of particles with the Earth's magnetosphere, as sometimes described for the aurora.>>
Art Neuendorffer

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Re: APOD: The Structured Tails of Comet NEOWISE (2020 Jul 22)

Post by XgeoX » Wed Jul 22, 2020 4:20 pm

Dang, this is beautiful and so is the illustration Neufer posted. Thank you!

Eric

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MarkBour
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Re: Comet Klinkenberg-Chéseaux

Post by MarkBour » Wed Jul 22, 2020 6:54 pm

neufer wrote:
Wed Jul 22, 2020 2:48 pm
http://en.wikipedia.org/wiki/C/1743_X1 wrote: In early March 1744, Chéseaux and several other observers reported an extremely unusual phenomenon — a 'fan' of six separate tails rose above the horizon. It has been suggested that the 'fan' of tails was generated by as many as three active sources on the cometary nucleus, exposed in turn to solar radiation as the nucleus rotated. It also has been proposed that the tail phenomenon was a very prominent example of the "dust striae" seen in the tails of some comets, such as Comet West and C/2006 P1 (McNaught).
Capture.png
Six tales in one (http://www.entwinedtales.com/)
Today's APOD is really beautiful -- great detail!


Thanks, Art, for the clip about the comet of 1744, that must have been truly spectacular.
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sillyworm 2

Re: APOD: The Structured Tails of Comet NEOWISE (2020 Jul 22)

Post by sillyworm 2 » Thu Jul 23, 2020 1:32 pm

Was able to get a good view of NEOWISE up on our property in Michigan.There was an hour window,after the reflected light of the sun on Lake Michigan and it passing the horizon,that we received an absolutely beautiful glimpse of the comet.It was truly a fantastic experience.