|Update: Exceeding all expectations, Comet Lovejoy has become a beautiful sight in predawn skies for far-southern observers — and has even been photographed from the International Space Station! Click here for details.|
For two weeks, comet aficionados around the world have wondered whether an inbound iceball dubbed C/2011 W3 — Comet Lovejoy — would survive this week's close pass with the Sun. The odds weren't good: perihelion would occur just 116,000 miles (186,200 km) from the searing solar surface.We all looked on as spaceborne cameras, most notably two C2 and C3 coronagraphs on the Solar and Heliospheric Observatory, kept vigil. In the days leading up to perihelion, the comet blazed in brilliance and developed a long, bright tail as it edged ever closer to the Sun.
At one point images showed a tiny fragment moving alongside the main mass. Had the comet split, or was it an undetected traveling companion? "Both — and neither," says SOHO scientist Karl Battams. He explains that it must be a piece of the parent body that fragmented long ago to create Comet Lovejoy and the thousands of other kamikaze objects known as Kreutz sungrazers.
The seemingly-doomed visitor disappeared late yesterday behind the coronagraphs' occulting masks. Perihelion came and went earlier today (at 00:30 Universal Time). Hours later, we were all stunned to see the comet reemerge from behind the opposite limb. In fact, the brilliant head could be seen on one side of the Sun, while what remained of its tail appeared on the opposite side.Comet Lovejoy had survived! Clearly, it wasn't the inconsequential interloper that almost all other Kreutz sungrazers are, literally vaporizing as they near the Sun. Instead, it must be roughly 1 km across or larger to have avoided complete incineration.
"We are witnessing one of the most extraordinary events in cometary history," notes John Bortle, who has observed and studied these objects for more than 40 years. "The manner in which Comet Lovejoy is evolving is, to my knowledge, totally unique in the comet record. Its brilliant, starlike appearance this morning, when only at an extremely small heliocentric distance, harkens back once again to the reports of 'brilliant stars' being occasionally reported close to the Sun down through history.""I can hardly believe it!" Lovejoy told me via email. "I didn't rate it much chance of surviving to be honest, certainly not the nucleus. This exceeded all my expectations, and the perihelion coverage by all the satellites was just astounding."
Remarkably, Southern Hemisphere observers are already on the lookout for the reemergence of this celestial phoenix in the predawn sky. No one has reported success yet, suggesting that the comet's head is no brighter than magnitude 2 or 2½ (according to Bortle). But I'll wager that Terry Lovejoy is already up and getting ready to look as I write this. His discovery of C/2011 W3 on December 2nd marked the first time a sungrazing comet had been found from the ground since 1970.
Click here to check out the latest SOHO images and movies of Comet Lovejoy's remarkable passage. You'll also enjoy reading Battam's frequently updated postings about it.