|Posted by Jeevan ॐ Mirthu Gupt on July 31, 2013 at 8:15 AM|
In this Hubble Space Telescope composite image taken in April 2013, comet ISON floats against a seemingly infinite backdrop of numerous galaxies and a handful of foreground stars. Credit: NASA, ESA, and the Hubble Heritage Team
Will the much talked about comet ISON, discovered by Russian amateur astronomers last year, turn out to be what some are calling the ‘comet of the century’ ? Not likely, says one researcher who has just concluded a preliminary study using the latest observations of the icy interloper. (Related: “New Comet Discovered.”)
Astronomer Ignacio Ferrin, from the University of Antioquia in Medellin, Colombia, believes that comet C/2012 S1 ISON may possibly fall apart before even reaching its closest encounter with the sun later this fall.
Stargazers were initially very excited when astronomers calculated the comet’s orbit and they realized it would be skimming the sun’s surface by only 700,000 miles (1.1 million kilometers) on November 28, 2013. But continual observations by both professional and amateur telescopes, including Hubble, have since shown that the comet has not brightened as expected.
“Comet ISON has presented a peculiar behavior,” said Ferrin in a press statement.
“The light curve has exhibited a ‘slowdown event’ characterized by a constant brightness with no indication of a brightness increase tendency. This slowdown took place around January 13, 2013. For 132 days after that date, and up to the last available observation, the brightness has remained constant.”
Ferrin interprets this lackluster behavior as meaning that the comet may not live up to all the hoopla.
That’s because during its closest encounter with the sun, the comet’s three-mile (five-kilometer) wide icy core – in the worst case scenarios- will either be torn apart by intense solar gravitational forces, or simply melted away by the scorching 2,700 degree temperatures, Ferrin says.
The consensus in the astronomical community is that it is especially unlikely that ISON will flare up to be as bright as the full moon, as some media accounts have reported.
For now, however, the comet is still currently out between the orbits of Mars and Jupiter, hurtling towards the Sun at 48,000 miles (77,000 kilometers) an hour. The latest infrared views from NASA’s Spitzer Space Telescope—taken in June—shows ISON’s nucleus spewing out a healthy 186,000-mile-long (299,000-kilometer-long) tail of carbon dioxide and dust as it melts due to the sun’s heat.
Will comet ISON blossom into a naked-eye comet, sporting a long, beautiful tail across the sky? Comets are notoriously unpredictable and can surprise even experts. Unfortunately, it’s now a wait-and-see game since the comet is currently lost in the glare of the sun and will only be visible again in early September.
One thing is for sure, ISON will make an uncomfortably close approach to the sun in just a few months. Thanks to an armada of telescopes on Earth and in space trained on this cosmic event, we will be witness to a rare spectacle no matter what’s in store for this sun-grazer.
By: Andrew Fazekas