Comet ISON

[Luther Blissett]

What woke ISON from the Oort Cloud?

Despite the popular media, predicting the brightness of a comet with a once-and-done pass like this is difficult. But in a year from now, we may be getting a spectacular show.

Both Melancholia and Tristan and Isolde have been occupying some of my thought space this year, so the similarity to the name Isolde is striking, at least for me personally.

http://en.m.wikipedia.org/wiki/C/2012_S1

[Ben D]

Perihelion is due to occur on 28 November 2013, at 18:37:45 UTC



Perihelion & Distance: LIVE Information....http://www.cometison2013.co.uk/perihelion-and-distance/

[Ben D]

http://www.spacedaily.com/reports/Will_comet_ISON_survive_its_near_brush_with_the_Sun_999.html

Will comet ISON survive its near brush with the Sun?

by Staff Writers Washington (AFP) Nov 28, 2013

US astrophysicists are split over what will happen when the comet ISON passes near the sun Thursday, but a majority think it will break apart.

Comets are frozen balls of space dust left over from the formation of stars and planets billions of years ago.

So when one of them zips close to a hot star, like the Sun, sometimes the icy core... melts.

"Many of us think it could break up into pieces, and some people think it won't survive at all" after its brush near the Sun, said comet expert Carey Lisse of the Johns Hopkins Applied Physics Laboratory during a telephone press conference.

But he conceded, there are others who think the icy mass "will actually survive and come back out" on the other side of the sun, albeit somewhat shrunken down from its encounter with the Sun's heat.

ISON will be just 1.17 million kilometers (727,000 miles) from the sun as it passes by where it will be hit by temperatures of around 2,700 degrees Celsius (4,900 Fahrenheit).

"I think it has a maybe 30 percent chance to make it" past the sun intact, Lisse said.

The comet "is like a loose snow ball," he explained, saying it is "maybe half or a third water and it's rather weak." It's also smaller than most comets, currently measuring around 1.2 kilometers in diameter.

"The average size for a comet is about three kilometers diameter, so this comet is maybe about half the size of the average, typical comet," he said.

Either way it turns out, astronomers are watching keenly.

"We have never seen a comet like this coming from the Oort cloud and going in the sun grazing orbit," said astrophysicist Karl Battams, of the Naval Research Laboratory in Washington.

We "don't really have any past experience we can use to judge or predict what is going to happen to this one," he said, adding it's "a very peculiar object but also a fascinating object."

Scientists say the comet comes from the very origin of the solar system, 4.5 billion years ago -- preserved "in deep freeze in the Oort cloud halfway to the next star for the last four and a half billion years," Lisse said.

If ISON survives its passage near the Sun, it will be visible at night from December through February, crossing nearest Earth -- about 64 million kilometers away) on December 26.

The US space agency is gathering a round table of astronomers on Thursday starting at 1700 GMT to answer questions from the public and from the scientific community as they follow the comet's brush with the Sun.

About Stereo...http://www.nasa.gov/mission_pages/stereo/news/gravity_parking.html

[Wombaticus Rex]

Ben D, superb links, thank you for the brainfood, especially the bit about STEREO, I didn't appreciate quite how rad that system was.

[Ben D]

Thank you Wombat.

A video from http://spaceweather.com/....latest developments...



In the movie, Comet ISON is clearly falling apart as it approaches the sun. Researchers working with the Solar Dynamics Observatory report that they are saw nothing along the track that ISON was expected to follow through the sun's atmosphere.

Update: Nevertheless, something has emerged from the sun's atmosphere. Watch this movie all the way to the end. Whether this is a small fragment of Comet ISON's nucleus or perhaps a "headless comet"--a stream of debris marking the remains of the comet's disintegrated core--remains to be seen.

COMET ISON--UPDATE: New images from SOHO show something emerging from behind the sun. It could be a small fragment of Comet ISON's nucleus or perhaps a "headless comet"--a stream of debris marking the remains of the comet's disintegrated core.

[Ben D]

Well it seems something survived, but it's on a very different trajectory than planned...



Image from SOHO..

[Ben D]

From sapceweather.com...

CANCEL THE EULOGY ... FOR NOW: Comet ISON flew through the sun's atmosphere on Nov. 28th and the encounter did not go well for the icy comet. Just before perihelion (closest approach to the sun) the comet rapidly faded and appeared to disintegrate. This prompted reports of ISON's demise. However, a fraction of the comet might have survived. Click on the image below to see what emerged from Comet ISON's brush with solar fire:

[Ben D]

Seems the verdict is in, ISON has been fatally wounded. Nice end tho..a Thanksgiving meal for the Solar Logos, ..a sacrifice..

http://www.digitaljournal.com/article/363018#ixzz2m1gvCwx0

Comet ISON disintegrates as it goes around the sun

Comet ISON, once deemed the "comet of the century," was destroyed Thursday during its encounter with the sun leaving behind a trail of dust that continued traveling through space, scientists say.

"It does seem that Comet ISON probably hasn't survived this journey," Karl Battams, an astrophysicist at the Naval Research Laboratory, said during a NASA sponsored Google + hangout according to NBC News.

"We see zero sign of a nucleus, which is not good," Battams said.

Solar physicist Alex Young said: "It's unfortunate that it doesn't appear that we'll see it," ABC News reports.

"For whatever reason, we don't know right now, we may never know the reason why it just was not stable enough or perhaps the gravity from the sun (was the cause)," Young said. "The gravity is so strong that each ends experience is different than the other end and that just tears and rips and pulls at the comet and in this case, perhaps it just experienced so much stress that it broke apart and once it broke into its little pieces then they all melted much quicker and perhaps we lost it."

Despite its large size, ISON was probably torn apart due to the immense heat and tidal forces near the Sun, BBC News reports.

The European Space Agency's twitter announced the death of ISON at 9:30 PM GMT.

Our Soho scientists have confirmed, Comet ISON is gone."

NASA's Veronica McGregor joked about ISON being destroyed on Thanksgiving. "The sun may have cooked Comet ISON. ... Now it's time for me to start cooking Thanksgiving dinner," she tweeted.

Comet ISON stands for International Scientific Optical Network. It was discovered over a year ago by Vitali Nevski and Artyom Novichonok.

[norton ash]

ISON the sun and the sun won. (Breakin' rocks in the hot sun.)

[Col Quisp]

Not so fast, there, varmints.
Update from Spaceweather:

'Cancel the funeral. Comet ISON is back from the dead. Yesterday, Nov. 28th, Comet ISON flew through the sun's atmosphere and appeared to disintegrate before the cameras of several NASA and ESA spacecraft. This prompted reports of the comet's demise. Today, the comet has revived and is rapidly brightening. (updated Nov. 29 @ 1800 UT):'

Before the flyby, experts had made many predictions about what might happen to the comet, ranging from utter disintegration to glorious survival. No one predicted both.

Karl Battams of NASA's Comet ISON Observing Campaign says, "[colleague] Matthew Knight and I are ripping our hair out right now as we know that so many people in the public, the media and in science teams want to know what's happened. We'd love to know that too! Right now, here's our working hypothesis:

"As comet ISON plunged towards to the Sun, it began to fall apart, losing not giant fragments but at least a lot of reasonably sized chunks. There's evidence of very large dust in the long thin tail we saw in the [SOHO coronagraph] images. Then, as ISON plunged through the corona, it continued to fall apart and vaporize, losing its coma and tail completely just like sungrazing Comet Lovejoy did in 2011. What emerged from the Sun was a small but perhaps somewhat coherent nucleus that has resumed emitting dust and gas for at least the time being."

Battams emphasizes that it is too soon to tell how big the remnant nucleus is or how bright the resurgent comet will ultimately become. "We have a whole new set of unknowns, and this ridiculous, crazy, dynamic and unpredictable object continues to amaze, astound and confuse us to no end. We ask that you please be patient with us for a couple of days as we analyze the data and try to work out what is happening."

Astrophotographer Babak Tafreshi has edited an HD video that compares views of ISON from both of SOHO's coronagraphs. "It seems the comet could become a naked eye object with several degrees of scattered tail by Dec 2nd or 3rd," he predicts. "It's not the comet of the century for sure, and fainter than the Lovejoy sungrazer in Dec. 2011, but an interesting imaging target is just a few nights away!"
http://spaceweather.com/


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Update from SOLARHAM:
http://www.solarham.net/index.htm
'Thursday was a day full of excitement and also many questions in regards to Comet ISON. The eyes of sky watchers around the world were tuned into a number of space weather websites wondering if the sungazing comet would survive its close encounter with our star. Comet ISON brightened throughout the day as it neared the sun, with a long dusty tail visible behind it in both LASCO and STEREO imagery. When it came time for the predicted perihelion (closest approach to the Sun) at 18:44 UTC, initial indications were that ISON did not survive the intense solar atmosphere and burned up. Comet ISON was declared dead by many. After a few hours had passed, what appeared to be a fragment of the comet re-emerged in both LASCO C2 and STEREO Ahead coronagraph imagery. Did ISON survive? Imagery and video below appear to support that scenario. More updates to follow regarding this event. Stay Tuned!'

Added 11/30/2013 @ 01:40 UTC
Bright CME and Comet ISON
Below is an updated image by LASCO C3 @ 00:08 UTC (Nov 30) showing a bright Coronal Mass Ejection (CME) leaving the sun, along with Comet ISON. The source of the CME appears to be from a position beyond the west limb and is directed away from Earth. In the image you also get an updated look at Comet ISON. The plasma cloud does should not have an impact on the comet.

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Update from Never a Straight Answer:
'Continuing a history of surprising behavior, material from Comet ISON appeared on the other side of the sun on the evening on Nov. 28, 2013, despite not having been seen in observations during its closest approach to the sun.

As ISON appeared to dim and fizzle in several observatories and later could not be seen at all by NASA's Solar Dynamics Observatory or by ground based solar observatories, many scientists believed it had disintegrated completely.

However, a streak of bright material streaming away from the sun appeared in the European Space Agency and NASA's Solar and Heliospheric Observatory later in the evening. The question remains whether it is merely debris from the comet, or if some portion of the comet's nucleus survived, but late-night analysis from scientists with NASA's Comet ISON Observing Campaign suggest that there is at least a small nucleus intact.'

[

[NaturalMystik]

11/29/13-- Despite early reports which declared Comet ISON dead, following its close encounter with the sun, astronomers have now observed evidence that the much-discussed comet survived the event, albeit missing a considerable amount of its original mass. More on the story at Discovery News.

Meanwhile, C2C science advisor, Richard C. Hoagland, provided us with images that suggest Comet ISON not only survived the solar rendezvous, but also changed course due to some mysterious force. Richard writes ...

Here is our Enterprise Mission evidence that ISON not only "survived" its close approach to the Sun on Thursday afternoon ... it's also now "changed course!"

These diagrams illustrate ISON's position early this AM, at 06:30 UTC -- overlaid on an official NASA plot of ISON's pre-perihelion projected orbit.

They're obviously NOT the same ....

"Something" dramatic happened around perihelion ... to not only fundamentally change the geometric shape of ISON's "coma" [it's now definitely "triangular" ... ("tetrahedral?")], but its trajectory as well; ISON is now following a significantly different, slower solar orbit away from the Sun than NASA calculated previously -- as can easily be seen in these Enterprise Mission orbit plots of the official NASA data.

So far, NASA has made NO "official comment."

http://www.coasttocoastam.com/pages/iso ... ges-course

Seems to me Hoaglands contention was that ISON was not a natural object... Take it with however many grains of salt you like.

[DrEvil]

It sure does seem like it's almost maneuvering. Maybe it's on a fuel run?

[NaturalMystik]

If it is indeed is not a man made object, then fuel run is a great theory. I'll have to check out enterprise mission and figure out why Hoagland thinks it is so... As much as I'd love to believe ISON is a UFO, it's probably just a boring chunk of dirt from the Oort cloud... Which still begs the question though, what knocked it loose and sent it trucking?

[Luther Blissett]

I can't help but feel that it did not change course after perihelion. Am I looking at it with too amateur of an eye?

[justdrew]

I can't help but feel that it did not change course after perihelion. Am I looking at it with too amateur of an eye?

didn't look like much of a course change to me either. It's a 3d trajectory flattened to a 2d image. Anyway, since it was unknown how much mass would disassociate with the nucleus, a perfect guesstimate would have been impossible to make.

Depending on what the dust is made of, the nucleus might have been fairly protected by the large could of material around it.