APOD: The Snows of Churyumov-Gerasimenko (2024 Jan 06)

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APOD: The Snows of Churyumov-Gerasimenko (2024 Jan 06)

Post by APOD Robot » Sat Jan 06, 2024 5:06 am

Image The Snows of Churyumov-Gerasimenko

Explanation: You couldn't really be caught in this blizzard while standing by a cliff on periodic comet 67P/Churyumov-Gerasimenko. Orbiting the comet in June of 2016, the Rosetta spacecraft's narrow angle camera did record streaks of dust and ice particles similar to snow as they drifted across the field of view close to the camera and above the comet's surface. Still, some of the bright specks in the scene are likely due to a rain of energetic charged particles or cosmic rays hitting the camera, and the dense background of stars in the direction of the constellation of the Big Dog (Canis Major). In the video, the background stars are easy to spot trailing from top to bottom. The stunning movie was constructed from 33 consecutive images taken over 25 minutes while Rosetta cruised some 13 kilometers from the comet's nucleus. In September 2016, the nucleus became the final resting place for the Rosetta spacecraft after its mission was ended with a successful controlled impact on 67P/Churyumov-Gerasimenko.

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Re: APOD: The Snows of Churyumov-Gerasimenko (2024 Jan 06)

Post by AVAO » Sat Jan 06, 2024 10:28 am

APOD Robot wrote: Sat Jan 06, 2024 5:06 am Image The Snows of Churyumov-Gerasimenko
The X-account and astrodon-account from Jacint Roger Perez (landru79) with all the GIFs of Churyumov-Gerasimenko are very, very cool. Well done.

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Re: APOD: The Snows of Churyumov-Gerasimenko (2024 Jan 06)

Post by AVAO » Sat Jan 06, 2024 10:37 am

neufer wrote: Thu Apr 26, 2018 12:45 pm
Click to play embedded YouTube video.
Heaven is where everything is white!
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Older discussions:
viewtopic.php?t=38236
viewtopic.php?t=40370

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Re: APOD: The Snows of Churyumov-Gerasimenko (2024 Jan 06)

Post by Ann » Sat Jan 06, 2024 11:32 am

AVAO wrote: Sat Jan 06, 2024 10:37 am
neufer wrote: Thu Apr 26, 2018 12:45 pm
Click to play embedded YouTube video.
Heaven is where everything is white!
Tribute to Neufer



Older discussions:
viewtopic.php?t=38236
viewtopic.php?t=40370
:D :thumb_up:

And I think Neufer approves.

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Re: APOD: The Snows of Churyumov-Gerasimenko (2024 Jan 06)

Post by johnnydeep » Sat Jan 06, 2024 3:19 pm

I assume that the longer a streak is the more likely it is due to a charged particle or cosmic ray hitting the detector? Hmm, but why do those cause streaks anyway? Is it because they strike the detector at an angle (the farther from orthogonal to the plane of the detector, the longer the streak) and trigger multiple pixels during each exposure?
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Re: APOD: The Snows of Churyumov-Gerasimenko (2024 Jan 06)

Post by alex555 » Sat Jan 06, 2024 9:57 pm

At a given moment in the video, around 0:02, very close to the large cliff, we can see a globular cluster

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Re: APOD: The Snows of Churyumov-Gerasimenko (2024 Jan 06)

Post by rwlott » Sat Jan 06, 2024 10:33 pm

AVAO wrote: Sat Jan 06, 2024 10:37 am
neufer wrote: Thu Apr 26, 2018 12:45 pm
Click to play embedded YouTube video.
Heaven is where everything is white!
Tribute to Neufer
I sure do miss Neufer. APOD hasn't been the same since Art left us. And now Orin's gone, too.

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Re: APOD: The Snows of Churyumov-Gerasimenko (2024 Jan 06)

Post by johnnydeep » Sat Jan 06, 2024 11:11 pm

alex555 wrote: Sat Jan 06, 2024 9:57 pm At a given moment in the video, around 0:02, very close to the large cliff, we can see a globular cluster
Or an open cluster? I don't think there are enough stars for it to warrant being deemed a globular cluster.

Extra points if someone can identify it!
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Re: APOD: The Snows of Churyumov-Gerasimenko (2024 Jan 06)

Post by Ann » Sun Jan 07, 2024 4:54 am

johnnydeep wrote: Sat Jan 06, 2024 11:11 pm
alex555 wrote: Sat Jan 06, 2024 9:57 pm At a given moment in the video, around 0:02, very close to the large cliff, we can see a globular cluster
Or an open cluster? I don't think there are enough stars for it to warrant being deemed a globular cluster.

Extra points if someone can identify it!
The only cluster I can think of that bears the slightest resemblance to it is NGC 2362, the Tau Canis Majoris cluster.


But when we are talking about open clusters, there are many possible candidates. Around 1100 open clusters have been detected in the Milky Way, according to ESA/Hubble.

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Re: APOD: The Snows of Churyumov-Gerasimenko (2024 Jan 06)

Post by AVAO » Sun Jan 07, 2024 8:56 am

rwlott wrote: Sat Jan 06, 2024 10:33 pm
AVAO wrote: Sat Jan 06, 2024 10:37 am
neufer wrote: Thu Apr 26, 2018 12:45 pm
Click to play embedded YouTube video.
Heaven is where everything is white!
Tribute to Neufer
I sure do miss Neufer. APOD hasn't been the same since Art left us. And now Orin's gone, too.
This is certainly the case. Unfortunately, in cosmic dimensions, each of us is only granted a short stay on this wonderful planet for a blink of an eye.

We have eyes - now technically expanded - to briefly look up into nature, sky and the universe and to feel humble when we see the size and beauty of the universe compared to our negligible tinyness. The fact that we as humans have lost this humility is one of the reasons why we were able to completely devastate our home planet - previously also called the Garden of Eden - with brute force and in just a few decades without feeling guilty about it.
Just to cry.

I'm sure there are an astronomical number of cats in Orin's heaven - that gives me a smile in return :-)

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Re: APOD: The Snows of Churyumov-Gerasimenko (2024 Jan 06)

Post by johnnydeep » Sun Jan 07, 2024 6:41 pm

Ann wrote: Sun Jan 07, 2024 4:54 am
johnnydeep wrote: Sat Jan 06, 2024 11:11 pm
alex555 wrote: Sat Jan 06, 2024 9:57 pm At a given moment in the video, around 0:02, very close to the large cliff, we can see a globular cluster
Or an open cluster? I don't think there are enough stars for it to warrant being deemed a globular cluster.

Extra points if someone can identify it!
The only cluster I can think of that bears the slightest resemblance to it is NGC 2362, the Tau Canis Majoris cluster.


But when we are talking about open clusters, there are many possible candidates. Around 1100 open clusters have been detected in the Milky Way, according to ESA/Hubble.

Ann
Thanks Ann. That could be it for all I know. It's a pity that the links to images at the ESA Hubble site link are stale, e.g., this one (and the one at the similar "globular cluster" page) - https://cdn.spacetelescope.org/archives ... w2134a.jpg

As for identifying this particular cluster, I'm sure someone sufficiently clever could use the "familiar" stars in the background for guidance, although ignoring the non-stars presents a special challenge. Here's the clearest image from among the consecutive ones that make up this video:

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Re: APOD: The Snows of Churyumov-Gerasimenko (2024 Jan 06)

Post by Knight of Clear Skies » Mon Jan 08, 2024 8:06 pm

Ann wrote: Sun Jan 07, 2024 4:54 am The only cluster I can think of that bears the slightest resemblance to it is NGC 2362, the Tau Canis Majoris cluster.

...

Ann
Wow. Great call Ann, I was able to plate solve @johnnydeep's screengrab and that's what it came up with too.

https://worldwidetelescope.org/webclien ... ov=5.41236
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Re: APOD: The Snows of Churyumov-Gerasimenko (2024 Jan 06)

Post by johnnydeep » Mon Jan 08, 2024 8:19 pm

Knight of Clear Skies wrote: Mon Jan 08, 2024 8:06 pm
Ann wrote: Sun Jan 07, 2024 4:54 am The only cluster I can think of that bears the slightest resemblance to it is NGC 2362, the Tau Canis Majoris cluster.

...

Ann
Wow. Great call Ann, I was able to plate solve @johnnydeep's screengrab and that's what it came up with too.

https://worldwidetelescope.org/webclien ... ov=5.41236
Wow! I'm very impressed with both Ann's guess and your verification!!
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Re: APOD: The Snows of Churyumov-Gerasimenko (2024 Jan 06)

Post by Ann » Mon Jan 08, 2024 9:21 pm

Knight of Clear Skies wrote: Mon Jan 08, 2024 8:06 pm
Ann wrote: Sun Jan 07, 2024 4:54 am The only cluster I can think of that bears the slightest resemblance to it is NGC 2362, the Tau Canis Majoris cluster.

...

Ann
Wow. Great call Ann, I was able to plate solve @johnnydeep's screengrab and that's what it came up with too.

https://worldwidetelescope.org/webclien ... ov=5.41236
Thank you for identifying the cluster! I'm impressed that you were able to! And I'm very glad that I managed to get the cluster right.

The reason why I could tentatively identify it is that alex555 described it as a globular cluster, but johnnydeep pointed out that it doesn't contain enough stars to be a globular. So the cluster we were looking for looked like a globular in its spherical shape and typical brightness distribution, with a steeply rising brightness in the center. I could only think of one open cluster that looks like that, and that is NGC 2362. This is what it looks like in Simbad's astronomical database:

NGC 2362 DSS.png

The reason why NGC 2362 looks like that is that the B-type members are perfectly spherically distributed around the supergiant central star, Tau Canis Majoris. I know of no other open cluster that looks like that. Compare it, for example, with NGC 3293, which is quite rich, compact and spherical as open clusters go, but not nearly as bright in the center as NGC 2362:


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Re: APOD: The Snows of Churyumov-Gerasimenko (2024 Jan 06)

Post by johnnydeep » Mon Jan 08, 2024 10:47 pm

Ann wrote: Mon Jan 08, 2024 9:21 pm
Knight of Clear Skies wrote: Mon Jan 08, 2024 8:06 pm
Ann wrote: Sun Jan 07, 2024 4:54 am The only cluster I can think of that bears the slightest resemblance to it is NGC 2362, the Tau Canis Majoris cluster.

...

Ann
Wow. Great call Ann, I was able to plate solve @johnnydeep's screengrab and that's what it came up with too.

https://worldwidetelescope.org/webclien ... ov=5.41236
Thank you for identifying the cluster! I'm impressed that you were able to! And I'm very glad that I managed to get the cluster right.

The reason why I could tentatively identify it is that alex555 described it as a globular cluster, but johnnydeep pointed out that it doesn't contain enough stars to be a globular. So the cluster we were looking for looked like a globular in its spherical shape and typical brightness distribution, with a steeply rising brightness in the center. I could only think of one open cluster that looks like that, and that is NGC 2362. This is what it looks like in Simbad's astronomical database:


NGC 2362 DSS.png


The reason why NGC 2362 looks like that is that the B-type members are perfectly spherically distributed around the supergiant central star, Tau Canis Majoris. I know of no other open cluster that looks like that. Compare it, for example, with NGC 3293, which is quite rich, compact and spherical as open clusters go, but not nearly as bright in the center as NGC 2362:


Ann
Nice work guys - NGC 2362 is quite an interesting - and large! - open cluster as well! From Wikipedia:
https://en.wikipedia.org/wiki/NGC_2362 wrote:The cluster is located at a distance of approximately 1.48 kpc from the Sun,[1] and appears associated with the giant nebula Sh2-310 that lies at the same distance,[7] about one degree to the east. This giant H II region is being ionized by the brighter members of the NGC 2362 cluster.[4]

NGC 2362 is a relatively young 4–5 million years in age[3] but is devoid of star-forming gas and dust, indicating that the star formation process has come to a halt.[4] It is a massive open cluster, with more than 500 solar masses,[3] an estimated 100-150 member stars, and an additional 500 forming a halo around the cluster. Of these cluster members, only around 35 show evidence of a debris disk.[3] There is one slightly evolved O-type star, Tau Canis Majoris, and around 40 B-type stars still on the main sequence. Only one candidate classical Be star has been found, as of 2005.[4]
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Re: APOD: The Snows of Churyumov-Gerasimenko (2024 Jan 06)

Post by Knight of Clear Skies » Tue Jan 09, 2024 9:49 am

Ann wrote: Mon Jan 08, 2024 9:21 pm The reason why NGC 2362 looks like that is that the B-type members are perfectly spherically distributed around the supergiant central star, Tau Canis Majoris. I know of no other open cluster that looks like that. Compare it, for example, with NGC 3293, which is quite rich, compact and spherical as open clusters go, but not nearly as bright in the center as NGC 2362:

...

Ann
You certainly know your clusters Ann. I guess it must be a very young cluster, to have a supergiant in the middle of it.

I was surprised the plate solving software came back with a result given the badly trailing stars and mess of dust and cosmic ray artifacts. But I guess the algorithm is pretty good at finding the centre of any points. Thinking about it, it does have to deal with diffraction spikes.
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