Northern skywatchers are longing for a nice, bright comet to grace their skies — the kind of celestial spectacle that Comet McNaught (C/2006 P1) put on a few years ago for those Down Under.
When discovered last December, Comet Elenin (C/2010 X1) had the potential to at least crack the naked-eye-visibility threshold. OK, it was never going to be a McNaught or Hale-Bopp, but we're getting a little desperate up here north of the equator. The prediction was that Comet Elenin's inbound course would loop around the Sun at a distance of just 0.48 astronomical unit (45 million miles) on September 10th, followed by a quick climb into predawn skies for a couple weeks of nice visibility as it passed 0.23 a.u. from Earth in mid-October.
Alas, it was not to be. About 10% of such long-period comets randomly break apart on their first visits to the inner solar system, and Comet Elenin drew the short straw. By April the icy interloper was showing signs of pooping out, and it appeared to completely self-destruct about three weeks before perihelion.
"Disintegrating comets (as opposed to splitting ones) do not survive very long after the process has been observed to begin, which in the case with Comet Elenin was all the way back in the end of August," explains John Bortle, who's tracked the passages of these icy bodies for more than 50 years. "The decline/fade of Elenin was abrupt and dramatic."
Still, diehard observers have continued to look for the disrupted object's remains, with little success. Juan José González reports spotting a faint, diffuse cloud twice, on October 9th and 21st, from the summit of Alto del Castro (5,600 feet, 1,720 m) in northern Spain. It's a sighting claim that other comet observers, many armed with deep-probing cameras, dispute.
Putting the long-running "visual vs. CCD" debate aside, there's no question that Comet Elenin is — er, was — nothing like the Earth-threatening behemoth proffered by fringy pseudoscientists earlier this year. Using a remote-operated observatory in New Mexico, observers Ernesto Guido, Giovanni Sostero, and Nick Howes managed to record a wispy cloud at the comet's predicted location on October 21st and again on the 23rd. "The 'cloud' is roughly 40 arcminutes long with an extension of 6 arcminutes near the expected position of the comet," notes the report on their website.
In the meantime, comet-starved skygazers can always look to the stars of Hercules, where you'll find Comet Garradd (C/2009 P1) coasting along. It's not going to get much brighter than 7th magnitude, but on the other hand it'll stay nearly that brightness — and in the same region of sky —through January. So download S&T's finder chart, get those binoculars out, and have a look!