Did Comet ISON survive? Scientists see tiny hope

[Buster's Uncle]

Did Comet ISON survive? Scientists see tiny hope
Associated Press
2 hours ago



In this frame grab taken from enhanced video made by NASA's STEREO-A spacecraft, comet ISON, left, approaches the sun on Nov. 25, 2013. Comet Encke is shown just below ISON, The sun is to the right, just outside the frame. ISON, which was discovered a year ago, is making its first spin around the sun and will come the closest to the super-hot solar surface on Thanksgiving Day, Thursday, Nov. 28, 2013, at 1:37 p.m. EST. (AP Photo/NASA)



STOCKHOLM (AP) — A comet that gained an earthly following because of its bright tail visible from space was initially declared dead after essentially grazing the sun. Now, there is a silver of hope that Comet ISON may have survived.

New images, basically faint smudges on a screen, being analyzed Friday showed a streak of light moving away from the sun that some said could indicate it wasn't game over just yet.

"It certainly appears as if there is an object there that is emitting material," said Alan Fitzsimmons, an astronomer at Queens University in Belfast, Northern Ireland.

Basically a dirty snowball from the fringes of the solar system, scientists had pronounced Comet ISON dead when it came within 1 million miles (1.6 million kilometers) of the sun Thursday.

Some sky gazers speculated early on that it might become the comet of the century because of its brightness, although expectations dimmed over time. But it wouldn't be all bad news if the 4.5-billion-year-old space rock broke up into pieces, because some scientists say they might be able to study them and learn more about comets.

The European Space Agency, which had declared ISON's death on Twitter late Thursday, was backtracking early Friday, saying the comet "continues to surprise."

Comet ISON was first spotted by a Russian telescope in September last year, and became something of celestial flash in the pan this week for its vivid tail — visible by the naked eye — and compelling backstory of impending doom.

The comet was two-thirds of a mile wide as it got within 1 million miles (1.6 million kilometers) of the sun, which in space terms basically means grazing it.

NASA solar physicist Alex Young said Thursday the comet had been expected to show up in images from the Solar Dynamics Observatory spacecraft at around noon eastern time (1700 GMT), but almost four hours later there was "no sign of it whatsoever."

Images from other spacecraft showed a light streak continuing past the sun, but Young said that was most likely a trail of dust continuing in the comet's trajectory.

However, instead of fading, that trail appeared to get brighter Friday, suggesting that "at least some small fraction of ISON has remained in one piece," U.S. Navy solar researcher Karl Battams wrote on his blog. He cautioned that even if there is a solid nucleus, it may not survive for long.

Two years ago, a smaller comet, Lovejoy, grazed the sun and survived, but fell apart a couple of days later.

"This is what makes science interesting," said Fitzsimmons, who specializes in comets and asteroids. "If we knew what was going to happen, it wouldn't be interesting."

ISON's slingshot toward the sun left astronomers puzzled and excited at the same time.

Made up of loosely packed ice and dirt, the space rock came from the Oort cloud, an area of comets and debris on the fringes of the solar system.


http://news.yahoo.com/did-comet-ison-survive-scientists-see-tiny-hope-093132207.html

[Buster's Uncle]

Thanksgiving Comet Gets Gobbled Up
ISON Makes Fatal Approach to the Sun
By Gautam Naik Updated Nov. 28, 2013 2:32 p.m. ET



A pristine comet called ISON, which left its home at least a million years ago, will be making its closest approach to the sun on Thanksgiving day



A new guest arrived just in time for Thanksgiving dinner, but apparently didn't survive the festivities.

The visitor, a pristine comet called ISON that left its home at least a million years ago, made its closest approach to the sun Thursday afternoon.

But based on images arriving from various spacecraft, the consensus among scientists appeared to be that ISON, like the mythical Icarus, didn't survive its close encounter with the sun.

The comet's sweep near the sun was a moment that thousands of astronomers around the world had anxiously awaited, and before hopes dimmed about its survival, ISON was predicted to possibly loop around the star and emerge as a bright object visible to the naked eye in the skies of the Northern Hemisphere.

However, scientists now suspect it fragmented into countless pieces—never to be seen again.

Before the close approach, observations "showed that the comet had brightened and then lost brightness. So there's a lot of conjecture that it might be fading," said Padma Yanamandra-Fisher, a planetary scientist at the Space Science Institute in Boulder, Colo., before the comet made its close pass with the sun.



Comet ISON approaches the sun as seen by a NASA spacecraft on Nov. 25, 2013. U.S. National Aeronautics and Space Administration


Since it was spotted more than a year ago, ISON's behavior has constantly surprised astronomers, and they had held out hope that the comet could still put on a pretty display. On Monday, for example, it looked like it wouldn't survive. Yet it was still there on Tuesday.

In addition to being a cosmic tease, ISON was one of the most tracked comets in history.

Thousands of telescopes—amateur, professional and space-borne—were being trained on this relatively tiny clump of ancient rock and ice no more than three or four miles in diameter.

The comet was discovered in September 2012 by Russian astronomers Vitali Nevski and Artyom Novichonok using data from the International Scientific Optical Network, whose initials provided the name.

Nothing like ISON has been seen in living memory. It is a relatively rare "sungrazer," a comet that flies especially close to our sun.

Unlike periodic comets that come and go like the famous Halley's, ISON is pristine and was making its first journey toward the sun. Its composition—mainly rock and ice—has barely changed since it formed some 4.5 billion years ago, making it one of the oldest objects in the solar system.

That had scientists intrigued, because ISON's proximity to the sun, and the chance to study what it is made of, could provide valuable clues about origins of the solar system.

When a new comet flies close to the sun, the tremendous heat can help reveal rarer materials, such as metals, of which it is made.

"It's the first time in 200 years that we've seen a comet that's both a sungrazer and brand new," said Matthew Knight from the Lowell Observatory in Arizona.

Comet ISON left its home in the faraway Oort cloud—a vast area of cosmic debris a long way from the sun.

Remarkably, space telescopes have managed to film the latter part of its passage through the solar system.

At the beginning of November, ISON was traveling at 95,000 miles an hour. Since then, the sun's gravitational pull on it had gotten stronger and stronger. If it had survived its close encounter, ISON was expected to reach a speed of 845,000 miles an hour later on Thursday, catapulting around the sun at perihelion, its closest point to the solar surface.

At that point, it would have been about 1.9 million miles from the sun, a mere hop, skip and jump in cosmic terms. But the sun's heat and gravitational pull at that point would prove overpowering.

If ISON had survived, scientists predicted it would have been poised to put on a display in the first week of December, at least for Northern Hemisphere viewers.

"It would have a very long and bright tail as it comes up from the horizon shortly before sunrise," said Dr. Knight, before Thursday's fatal close encounter.

"If you go out 30 minutes before [sunrise], you should be able to see it with the naked eye."

But that was only if ISON had survived Thursday's flyby.


http://online.wsj.com/news/articles/SB10001424052702303562904579226000269988992

[Buster's Uncle]

Comet ISON Gets Roasted by Sun and Vanishes, But Did It Survive?
SPACE.com
By Tariq Malik 3 hours ago






Call it a cosmic holiday miracle. The much-anticipated Comet ISON appeared to disintegrate during its Thanksgiving Day slingshot around the sun Thursday, but something — it seems — may have survived.

The sungrazing Comet ISON vanished from the view of NASA's Solar Dynamics Observatory (SDO) during an extremely close encounter with the sun on Thursday (Nov. 28), leading scientists to suspect the worst.

"We didn't see Comet ISON in SDO," said Dean Pesnell, project scientist for SDO. "So we think it must have broken up and evaporated before it reached perihelion."

But late Thursday night, images from another sun-watching spacecraft, the Solar and Heliospheric Observatory (SOHO) run by NASA and the European Space Agency, picked up a blip of something rounding the sun in a camera called LASCO C3.

"Now, in the latest LASCO C3 images, we are seeing something beginning to gradually brighten up again," comet expert Karl Battams, of the U.S. Navy Research Laboratory in Washington, D.C., wrote in an evening blog post.  "One could almost be forgiven for thinking that there's a comet in the images!"



This image shows Comet ISON extremely close to the sun as seen by the SOHO spacecraft on Nov. 28, 2013


Roasted by the sun

Comet ISON came within 684,000 miles (1.1 million kilometers) of the sun's surface during its Thanksgiving Day solar passage, and was subjected to extreme gravitational forces and solar wind during the encounter. The comet's survival was always an open question since it was first discovered by Russian amateur astronomers Vitali Nevski and Artyom Novichonokin September 2012.  [Comet ISON's Sun Encounter: Complete Coverage]

Going into the solar rendezvous, Comet ISON was less than a mile wide and made up of 2 billion tons of ice and dust, NASA scientists said. What the comet, or comet fragment is now, though remains to be seen as scientists review images from SOHO and NASA's twin STEREO sun observatories.

"We have no way to estimate nucleus size from SOHO or STEREO and it's just way too early to speculate on ISON's future," Battams told SPACE.com in an email. "It is only a few hours old if we consider its survival as a 'rebirthing.'"


Astronomers and skywatchers had high hopes for Comet ISON. Its discovery 14 months ago gave scientists an unprecedented lead time to track the comet. Because of its close approach to the sun, the comet had the potential to become a brilliant object in the night sky, leading some scientists to dub ISON a potential "comet of the century."



Ben Leshchinsky sent SPACE.com this image of Comet C/2012 S1 ISON over Oregon's Willamette Valley


Interest was so high that Battams and his colleagues assembled a Comet ISON Observing Campaign in conjunction with NASA to track the comet. NASA spacecraft, including orbiters around Mars, Mercury as well as the Hubble Space Telescope, photographed the comet from space while amateur and professional astronomers observed it from Earth.

Scientists also hoped to learn more about the building blocks of our solar system from ISON, which is a relic from the formation of the Earth and other planets 4.5 billion years ago.

Comet ISON comes from the Oort cloud, a vast realm of icy objects that surrounds the outer solar system. By studying the comet's orbit, scientists think this is ISON's first trip to the inner solar system, and that the comet won't return for millions of years, if ever.



This NASA graphic shows the possible location of Comet ISON in the December night sky if the comet has survived


A visible comet once more?

While Comet ISON did not brighten as scientists had hoped on its way into the inner solar system, it did flare up to become visible to the naked eye in recent weeks as it neared the sun. If it survived the trip around the sun, some scientists were hopeful the comet would brighten enough to remain visible to the unaided eye.

"As December goes on, it will get farther way from the sun, and it will be up in the night sky," NASA scientist Michelle Thaller of the Goddard Space Flight Center said before the solar passage. "By the time you get to mid to late December, if you look up to about the Big Dipper, it should be right there if it survives the sun."

Over the next few days, Battams and other scientists will be monitoring the Comet ISON remnant to see how much of the comet, if any, has truly survived, as well as what it may mean for skywatchers on Earth.

"I think the next couple of days will be interesting and hopefully that will be enough time to figure out what is really going on," solar astrophysicist C. Alex Young told SPACE.com. "On its journey here, ISON has been an odd comet for many of the comet experts and it continues to not disappoint."


http://news.yahoo.com/comet-ison-gets-roasted-sun-vanishes-did-survive-145840058.html

[Buster's Uncle]

No sign of comet after pass around sun: scientists
Reuters
By Irene Klotz 22 hours ago



The Comet ISON is pictured in this handout image from a November 25, 2013 footage from the STEREO-A spacecraft



(Reuters) - A comet's 5.5-million-year journey to the inner solar system apparently ended during a suicidal trip around the sun, leaving no trace of its once-bright tail or even remnants of rock and dust, scientists said on Thursday.

The comet, known as ISON, was discovered last year when it was still far beyond Jupiter, raising the prospect of a spectacular naked-eye object by the time it graced Earth's skies in December.

Comet ISON passed just 730,000 miles (1.2 million km) from the surface of the sun at 1:37 p.m. EST/1837 GMT on Thursday. Astronomers used a fleet of solar telescopes to look for the comet after its slingshot around the sun, but to no avail.

"I'm not seeing anything that emerged from the behind the solar disk. That could be the nail in the coffin," astrophysicist Karl Battams, with the Naval Research Laboratory in Washington, said during a live broadcast on NASA TV."

"It's sad that it seemed to have ended this way, but we're going to learn more about this comet," he added.



Comet ISON is pictured in this November 19, 2013 handout photo by NASA, taken using a 14-inch telescope


At closest approach, the comet was moving faster than 217 miles per second(350 km per second) through the sun's atmosphere.

At that distance, it reached temperatures of 5,000 degrees Fahrenheit(2,760 degrees Celsius) - hot enough to vaporize not just ices in the comet's body, but dust and rock as well.

If the comet or any large fragments survived the close encounter with the sun, they would be visible to the naked eye in Earth's skies in a week or two.

The comet was discovered last year by two amateur astronomers using Russia's International Scientific Optical Network, or ISON.

Comets are believed to be frozen remains left over from the formation of the solar system some 4.5 billion years ago.

The family of comets that ISON belongs to resides in the Oort Cloud, located about 10,000 times farther away from the sun than Earth, halfway to the next star.

Occasionally, an Oort Cloud comet is gravitationally nudged out of the cloud by a passing star and into a flight path that millions of years later brings it into the inner solar system. Computer models show ISON was a first-time visitor.

"I hope we see another one soon," said Dean Pesnell, project scientist for NASA's Solar Dynamics Observatory.


http://news.yahoo.com/no-sign-comet-pass-around-sun-scientists-203418044.html

[Buster's Uncle]

Comet ISON reappears in new NASA images, scientists say nucleus 'may still be intact'
By Chris Welch on November 29, 2013 12:55 pm



Despite earlier evidence that comet ISON had burned up and disintegrated during a close encounter with the sun, NASA now believes the comet may have survived the heat. New imagery captured last night shows material from the comet heading up and away from the sun, and scientists believe a small nucleus could still be intact. That's according to "late-night analysis" from scientists that are part of NASA's comet ISON Observing Campaign. Before this latest discovery, a series of images that showed a comet trail (but no comet) led some observers to declare ISON as an "ex-comet."

But NASA says ISON's reemergence continues "a history of surprising behavior" that has seen the comet brighten and dim "in unexpected ways." According to the space agency, these variations in brightness are the result of material boiling off the comet and provide valuable clues as to just what ISON is made of.





http://www.theverge.com/2013/11/29/5157440/comet-ison-reappears-new-nasa-images-nucleus-may-be-intact

[Geo]

Even if ISON brightens, the weather forecast here isn't good.  The Canary Isles experience uncharacteristically cloudy and even rainy weather in the parts it should be clear and dry.