Comet ISON is still shaping up to be one of the most spectacular comets of our lifetimes. On Friday afternoon, NASA released images and a report based on a two-month study of the oncoming comet with its Swift ultraviolet/optical telescope (UVOT), which includes the first estimates of how much debris the comet is shedding as it travels.
“Comet ISON has the potential to be among the brightest comets of the last 50 years,” said lead investigator Dennis Bodewits, who is also an astromomer at the University of Maryland at College Park (UMCP).
Among the findings: As of January 30, Comet ISON was losing about two-thirds the mass of a space shuttle every minute — around 112,000 pounds per minute.
Although the young comet is beginning to show a fuzzy tail, it isn’t yet streaming off much water. In fact, only 130 pounds a minute of all that weight is good old H2O. Instead, the particles that make up the “fuzz” are carbon dioxide or monoxide evaporating off the core.
Based on current data, the researchers think that the comet is around 3 miles across. They also believe that it’s probably making its first-ever trip around the solar system. The first real test of its brightness might come on Oct. 1, when it passes less than seven million miles from Mars, possibly providing a photo opportunity for the Mars Curiosity rover.
This month, many viewers enjoyed the appetizer — a delightful smaller comet called PanSTARRS. But that’s likely to be just a warm-up for the real thing.
When it was first discovered in September, some astronomers predicted that ISON might be brighter than the full moon, which means that it could even be visible during the day. In December, astronomers again predicted that if the comet held up on its journey, it will make its closest approach to the sun on November 28, providing spectacular viewing from October through January 2014.
While nothing is ever guaranteed with comets, the new report from the Swift suggested that ISON will be a true sungrazing comet getting as near as 730,000 miles from the sun. If it doesn’t completely collapse, it should instead stream off a truly spectacular tail. NASA said you may even be able to see it in broad daylight by holding up a hand to block the light from the sun.
Here’s the Jan. 30 UVOT photo taken by NASA’s Swift spacecraft when fuzzy comet ISON was 5,000 times fainter than anything we can see with human eyes:
Here’s a video that NASA’s Goddard Space Flight Center has created to show its path:
I admit it. I’m starting to get excited about comet ISON.
[black and white photo credit: NASA/Swift/D. Bodewits, UMCP]
[comet in Earth’s sky photo Hans Bernhard via Wikipedia Commons]