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| Space on Aug 30, 2011

Has Comet Elenin split in two or disintegrated?

Infamous Comet Elenin might be self-destructing. Its core appears elongated, and its brightness has decreased – telltale signs of a cometary break-up.

SkyandTelescope.com reported today (August 30, 2011) that the infamous Comet Elenin – which is now only two weeks from its closest passage to the sun, and was scheduled for an appearance in our skies later this year – appears to have “self-destructed.”

Images show the comet’s bright core becoming elongated and diffuse. And, within the past week, the comet’s brightness has declined by 50 percent, says S&T’s Senior Contributing Editor J. Kelly Beatty. According to him (and he should know, as a long-time astro-journalist and veteran observer of the skies), these are:

… telltale signs that its icy nucleus has either broken in two or disintegrated altogether.

Comet Elenin on May 5, 2011 when it was 170 million miles (274 million kilometers) from Earth. Each picture is a combination of frames taken through green, red, and infrared filters. The stars appear as three separate images because the comet moved between each frame. Via astronomers Paul Weissman, Michael Hicks, and James Somers. Hicks and Somers were using the 24-inch (0.6-meter) AstroMechanics telescope and CCD camera at JPL's Table Mountain Observatory.

Had you heard of Comet Elenin before this? Many have, and for all the wrong reasons. For a reason that astronomers don’t understand, this comet has been associated by doomsdayers with various prophecies (such as “Thirst and famine when the comet will pass” from Nostradamus: Century 2, Quatrain 62).

Yet it has behaved only as an ordinary comet after all. At its closest point to Earth – on October 16, 2011 – Elenin will pass 35 million kilometers (22 million miles) from us, or nearly 100 times the moon’s distance. No doomsday prophecies needed.

Comet LINEAR broke apart shortly after its perihelion on July 26, 2000. The upper image is before the breakup. The lower image, from the Hubble Space Telescope, is after the breakup. Notice that the pieces have comet tails. Image Credit: HST, University of Hawaii

Other comets have been known to break up or disintegrate on their passage into the inner solar system. One was Comet LINEAR (1999 S4), which disintegrated shortly after its passage closest to the sun in the year 2000. Later, to astronomers’ surprise and delight, the Hubble Space Telescope discovered a small armada of “mini-comets” left behind by what seemed to be a total disintegration of Comet LINEAR. The pieces – which were still traveling in LINEAR’s old orbit – had each grown short comet tails, as the image at right shows.

EarthSky spoke earlier this year to Don Yeomans of the Near-Earth Object Program Office at NASA’s Jet Propulsion Laboratory in Pasadena, California. He warned months ago that Comet Elenin might not put on a great show for earthly stargazers. Even then, he said, the comet looked “wimpy.”

In today’s S&T post, J. Kelly Beatty asked long-time comet-watcher John Bortle about Elenin. Four months ago, based on Elenin’s performance to that point, Bortle had cautioned:

The comet may be intrinsically a bit too faint to even survive perihelion passage.

Apparently, Bortle was right. Perihelion – an object’s closest point to the sun – comes just two weeks from now, on September 10, for Comet Elenin. In fact, Beatty said in his post:

… there’s speculation that this object or its remnants might not be around much longer.

Elenin is currently located in a place in the sky that is nearly impossible to view from northerly latitudes, like ours in the U.S., but Australian observers have reported the decrease in brightness and other changes.

Bottom line: Comet Elenin appears to have disintegrated, or at least split in two, according to an article posted today (August 30, 2011) by Kelly Beatty at SkyandTelescope.com. For reasons unknown to astronomers, this comet has come to be associated with doomsday prophecies. Now it looks as if the comet itself is the one that’s doomed. It might not survive its passage into the inner solar system.

Don Yeomans with the truth about Comet Elenin (May, 2011)

Icy heart of Comet Hartley 2 is tumbling, at a changing rate

Don Yeomans with the truth about close-passing asteroid Apophis

Kathryn Reese-Taylor on the Mayans and 2012