APOD: Almost Three Tails for Comet Encke (2017 Feb 20)

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APOD: Almost Three Tails for Comet Encke (2017 Feb 20)

Post by APOD Robot » Mon Feb 20, 2017 5:07 am

Image Almost Three Tails for Comet Encke

Explanation: How can a comet have three tails? Normally, a comet has two tails: an ion tail of charged particles emitted by the comet and pushed out by the wind from the Sun, and a dust tail of small debris that orbits behind the comet but is also pushed out, to some degree, by the solar wind. Frequently a comet will appear to have only one tail because the other tail is not easily visible from the Earth. In the featured unusual image, Comet 2P/Encke appears to have three tails because the ion tail split just near to the time when the image was taken. The complex solar wind is occasionally turbulent and sometimes creates unusual structure in an ion tail. On rare occasions even ion-tail disconnection events have been recorded. An image of the Comet Encke taken two days later gives a perhaps less perplexing perspective.

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Re: APOD: Almost Three Tails for Comet Encke (2017 Feb 20)

Post by ta152h0 » Mon Feb 20, 2017 5:40 am

must have come to the fork in the road that Mr Johnny Carson always warned us about
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Re: APOD: Almost Three Tails for Comet Encke (2017 Feb 20)

Post by Chris Peterson » Mon Feb 20, 2017 6:01 am

If the comet were active enough, as we passed across its orbital plane we might see an anti-tail formed by our perspective on the dust. That could yield a comet with four apparent tails!
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Re: APOD: Almost Three Tails for Comet Encke (2017 Feb 20)

Post by rstevenson » Mon Feb 20, 2017 1:16 pm

An image of the Comet Encke taken two days later gives a perhaps less perplexing perspective.
Not really. I can still see, though they're faint and rotated into a different orientation, the same three tails.

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Re: APOD: Almost Three Tails for Comet Encke (2017 Feb 20)

Post by Ann » Mon Feb 20, 2017 2:44 pm

I'll refrain from saying that APOD comet ion tails appear to have given up their customary blue hue.

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Fred the Cat
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Re: APOD: Almost Three Tails for Comet Encke (2017 Feb 20)

Post by Fred the Cat » Mon Feb 20, 2017 6:29 pm

Must be a happy comet. Wagging its tail. :puppy:

Our dog was sound asleep the other day. Tail wagging. Hopefully having nice dreams. :)

Comets too. :wink:
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Re: APOD: Almost Three Tails for Comet Encke (2017 Feb 20)

Post by Boomer12k » Tue Feb 21, 2017 12:46 am

Interesting...

I am going to be out for a few days... I go in tomorrow morning for wrist surgery as I broke it in my car accident... but will try to look in... but might not be up for commenting...

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Re: APOD: Almost Three Tails for Comet Encke (2017 Feb 20)

Post by MarkBour » Tue Feb 21, 2017 1:27 am

Boomer12k wrote:Interesting...

I am going to be out for a few days... I go in tomorrow morning for wrist surgery as I broke it in my car accident... but will try to look in... but might not be up for commenting...

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Oof! Hopefully your surgeon can get it all set back perfectly. I read that wrist repair is a delicate business. May you have a full and pain-free recuperation.
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Re: APOD: Almost Three Tails for Comet Encke (2017 Feb 20)

Post by Ann » Tue Feb 21, 2017 11:44 am

Boomer12k wrote:Interesting...

I am going to be out for a few days... I go in tomorrow morning for wrist surgery as I broke it in my car accident... but will try to look in... but might not be up for commenting...

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Oh, sorry to hear that, Boomer! Get well soon!

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Re: APOD: Almost Three Tails for Comet Encke (2017 Feb 20)

Post by DavidLeodis » Tue Feb 21, 2017 10:05 pm

In the information brought up through the "featured unusual image" link https://www.flickr.com/photos/fhhemmeri ... 84377@N22/ it states the image was acquired on 2017-02-14. However, on the image brought up through the http://www.damianpeach.com/deepsky/2p_e ... 2_16dp.jpg link in the "An image of the Comet Encke taken two days later gives a perhaps less perplexing perspective" sentence in the explanation it states that image was taken on 2016-02-16.

Based on the "taken two days later" the 2016 is presumably just a clerical error but I thought I would mention it.