As the U.S. celebrated Thanksgiving Day, Comet ISON suffered a pretty severe cosmic flesh wound as it flew perilously close to the sun. Many concluded that the dirty snowball had vaporized, but, it seems, reports of Comet ISON’s death are greatly exaggerated.
In observations by an armada of solar telescopes, ISON’s perihelion (point of closest approach in the comet’s orbit) was closely tracked and in the run-up to the grand Thanksgiving event at 1:45 p.m. EST, it seemed that the much-hyped “Comet of the Century” had turned into the Turkey of the Century.
As the comet took the plunge into the sun’s corona, images from the Solar and Heliospheric Observatory (SoHO) depicted a bright Comet ISON with huge tail and hopes were high for its survival. However, as it passed a little over a million miles from the sun’s “surface” (the photosphere), the comet’s nucleus noticeably shrunk and appeared to vaporize.
But after several hours of confusion and searching for ISON in SoHO, Solar TErrestrial RElations Observatory (STEREO) and Solar Dynamics Observatory (SDO) images, a noticeable trail of debris could be seen as the comet carried out its solar slingshot — adding weight to the idea that the comet had undergone catastrophic tidal stresses and solar heating, causing it to break apart.
Remarking on the debris stream, NASA’s Tony Phillips of Spaceweather.com said: “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.”
Then, in some striking images released by SoHO’s LASCO instrument (pictured top), which has a wide-angle view of the sun’s lower atmosphere (the corona), a very comet-like object appears to have survived after perihelion.
“Now, in the latest LASCO C3 images, we are seeing something beginning to gradually brighten up again,” said astrophysicist Karl Battams, of the U.S. Naval Research Laboratory, in a NASA Comet ISON Observing Campaign (CIOC) blog update. “One could almost be forgiven for thinking that there’s a comet in the images!”
Has Comet ISON succumbed to its fiery encounter, breaking up, leaving only a few pieces of ex-comet behind? Or has it really risen from the dead, re-brightening and set to dazzle our night skies as it swings back out into deep space? It’s too early to tell, but it’s also too early to write ISON off.
“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,” said Battems.
Watch ISON as it approached the sun on Nov. 28:
Image: A SoHO LASCO observation of Comet ISON shortly after perihelion — a component of the cometary nucleus appears to be re-brightening after close approach. Credit: NASA/ESA