A new comet will be lighting up the Northern Hemisphere in 2013.
A year from now, it is possible that “comet fever” will be running high when a newfound comet emerges into view in the evening sky. But while some scientists have high hopes for a spectacular 2013 sky show by the comet, it is still far from certain.
When astronomers at the University of Hawaii at Manoa announced last June that they had discovered the new comet, it was a distant and inconspicuous object. But preliminary calculations at once made it clear that this new object had the potential to become a naked-eye object of considerable interest for skywatching enthusiasts in the Northern Hemisphere. The comet may ultimately shine as bright as some of the brightest stars in the night sky, but will likely pale in comparison to the brilliant planet Venus.
The comet was christened C/2011 L4 (PANSTARRS). Comets are usually named after their discoverers, but in this case a large team of observers, computer scientists, and astronomers was involved, so the comet was named after the telescope.
PANSTARRS stands for Panoramic Survey Telescope And Rapid Response System. It’s a 1.8-meter prototype for a quartet of military-funded telescopes that astronomers hope to build on the lip of the extinct volcano Haleakala.
Finding Comet PANSTARRS
The comet was initially photographed on June 6 and was confirmed the following day. Actually, the comet had been unknowingly imaged nearly two weeks earlier, on May 24 from Arizona’s Mount Lemmon Observatory. [Amazing Photos of Halley’s Comet]
When it was discovered in the constellation Libra, Comet PANSTARRS was a 19th-magnitude object — so faint that only telescopes with sensitive electronic detectors could pick it up — some 759 million miles (1.2 billion kilometers) from the sun.
Astronomers measure the brightness of objects in space on a reverse scale; the higher an object’s magnitude, the dimmer it appears to observers. The comet was so far away that at first there was difficulty in pinning down the exact date of when it would arrive at perihelion – its closest point to the sun. Initial estimates suggested anytime from early next February to the middle of April of 2013.
When I first wrote about comet PANSTARRS June 27 of last year, the date of perihelion was set for next April 17. But I also said at the time: “It may yet change again, so stay tuned.”
And so it did, to March 9, 2013 — less than one year from today.
The comet will pass to within 28 million miles (45 million kilometers) of the sun on that date. Such an enormous change in solar distance would cause a typical comet to increase in brightness dramatically. And indeed, the comet has responded to the increasing solar warmth as it has approached the sun.
On Feb. 13, the comet had brightened to magnitude 14.5, or in other words, it had increased in brightness by more than 60 times since it was first seen last June. The comet still has a long way to go — it’s still over 500 million miles (820 million km) from both the sun and Earth — out near the orbit of Jupiter. But it still appears on target to possibly become a bright naked eye object by this time next year.
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