New Images Captured by Gemini Observatory Reveal Comet ISON Speeding Toward Sun
Comet ISON, dubbed the comet of the century, is steadily racing toward our sun. The sight should be spectacularly bright during late November in the twilight sky and should remain easily visible into early December. Now, the Gemini Observatory has captured a series of images that shows off the comet.
The time-sequence images, spanning early February through May 2013, show the comet's remarkable activity despite its current great distance from both the sun and Earth. The information gleaned from these images actually provides vital clues as to the comet's overall behavior--and what we should expect when watching for it in the night sky.
How bright the comet is largely depends on evaporation rates and how quickly it sheds its dust and water. Like all comets, ISON is made up of frozen gases mixed with dust. When Gemini obtained this particular time sequence, the comet ranged between roughly 455 to 360 million miles from the sun, or just inside the orbital distance of Jupiter. Each image shows the comet in the far red part of the optical spectrum, which emphasizes the comet's dusty material already escaping.
So what do these images tell astronomers about the comet? Currently, researchers are still working on preliminary analysis of the new Gemini data. However, it does seem that the comet's activity has been decreasing somewhat over the past month.
"Early analysis of our models shows that ISON's brightness through April can be reproduced by outgassing from either carbon monoxide or carbon dioxide," said Karen Meech, one of the astronomers analyzing the data, in a news release. "The current decrease may be because this comet is coming close to the sun for the first time, and a 'volatile frosting' of ice may be coming off revealing a less active layer beneath. It is just now getting close enough to the sun where water will erupt from the nucleus revealing ISON's inner secrets."
Currently, it's still possible that the comet could become spectacularly bright as it passes close to the sun. Yet it's still too early to predict what will happen to ISON. It's very possible that the comet will fizzle and instead produce a much less spectacular show.