wunderkammer: Comets, planets, and stars, photographed by STEREO, November 2013.

Comet ISON moves left-to-right. Comet Encke (smaller) moves downward across its path. In the background are Mercury (left) and Earth (right). The cloud that blows right-to-left across the image is matter ejected from the Sun (out of frame right).

30 images taken by STEREO A, 1 every 4 hours 22nd-26th November.

Image credit: NASA/STEREO. Animation: AgeOfDestruction.

Not strictly true - this’ll only happen if the comet survives its close encounter with the Sun with enough volatiles intact to make a nice tail by the time it’s close to Earth, which isn’t guaranteed.

If it does survive, though, this is going to be the comet of the century, outshining the full moon at night and possibly visible during the day.

It turns out that a nucleus-free dust cloud of comet ISON survived encounter with the Sun!

With a comet like this you just have to wait and see what will happen. It held together a long time, got very bright last night, faded this morning, then apparently fell apart. Still, there’s more observing to do, and of course much data over which to go through.
(Source. The last post on ISON here)

Comet ISON as seen from the ISS

This image reveals a pin-head sized view of an object which is actually the comet ISON. Hardware components of the orbital outpost and Earth’s atmosphere above the horizon take up most of the image. Most of the other bright dots in the sky are heavenly bodies. The comet is distinguishable by its tail.

Image credit: ISS038-E-007980 (23 Nov. 2013) 

RIP Comet ISON: scientists declare famous ‘sungrazer’ dead after Sun encounter

It’s time to accept reality: Comet ISON is dead.

Comet ISON broke apart during its highly anticipated solar flyby on Nov. 28, emerging from behind the sun as a diffuse cloud of dust that has since all but dissipated in the darkness of deep space, scientists say.

“At this point, it seems like there’s nothing left,” comet expert Karl Battams, of the U.S. Naval Research Laboratory in Washington, D.C., said here today at the annual meeting of the American Geophysical Union. “Comet ISON is dead; its memory will live on.”

Comet ISON, which was discovered by two Russian amateur astronomers in September 2012, was making its first trip to the inner solar system from the distant and frigid Oort Cloud. The comet skimmed just 684,000 miles (1.1 million kilometers) above the surface of the sun on Nov. 28.

Comet ISON’s perilous journey was tracked closely by skywatchers, who hoped the icy wanderer would put on a great celestial show, and scientists, who watched the gases boiling off ISON to learn more about comet composition and structure.

Both groups had hoped the viewing campaign would last beyond perihelion, or closest approach, but Comet ISON couldn’t survive the sun’s intense heat and powerful gravitational pull.

“It looks like dust production more or less stopped when the comet reached perihelion,” said Geraint Jones of University College London. “The comet continued to fade after perihelion, as it moved away from the sun.”

ISON gave one tantalizing hint that it may still be intact, brightening considerably a few hours after the perihelion passage. But that may simply have been a consequence of orbital dynamics and nothing more, Jones said.

Comet ISON’s fragment cloud likely stretched out as the icy object reached perihelion, with the more anterior pieces speeding up relative to the ones farther behind, Jones explained. This would have caused ISON to dim, and then re-brighten briefly as the fragments clumped up again on the other side of the sun.

Comet behavior is incredibly difficult to predict, so it’s tough to know exactly why ISON didn’t make it. But its disintegration may have something to do with the comet’s relatively small size. Recent observations by NASA's Mars Reconnaissance Orbiter (MRO) suggest that ISON’s nucleus was between 330 feet and 3,300 feet (100 to 1,000 meters) wide, scientists said today.

“It was probably smaller than maybe 600 meters [in] diameter,” said Alfred McEwen of the University of Arizona, principal investigator of MRO’s powerful HiRISE camera. “And from past sungrazing comets, those smaller than about half a kilometer, they don’t survive.”

While Battams and other experts have said their farewells to ISON, several NASA space telescopes will continue scanning the heavens just in case the comet makes a miraculous reappearance.

“NASA is going to try to look for it with Hubble, and I’ve heard that Spitzer and Chandra may be attempting observations as well,” Battams said. “That really is sort of a recovery mission, but I don’t know if we’re going to get any success with those.”

Image credit: Waldemar Skorupa


“Sungrazing” is an oxymoron
In spite of hopes and fantasy.
Nothing survives the touch of the Sun
(Save few like the Kreutz family).
Yet it is inexorable and fair
For comets’ deadly attempts.
Destined to keep on going,
They’re the Great Star’s contempt.
Like many have done before,
This mass of ice and dust
Ventured close to the Fire,
Bracing itself as it must,
‘Twas only around the corner,
The jubilation of the brilliance,
Endurance would keep it together
As it approached perihelion.
Wishing to mean something—
The comet of the century—
Not knowing that the Grace
Burns anything in its territory.
Like most other sungrazers,
It was defeated and gone,
Not a single trail left behind
To inspire with the coming of dawn.