Comet ISON (C/2012 S1) continues its highly publicized venture through space, heading perilously towards the extreme temperatures of the scorching sun.
A talented astrophotographer managed to snap a breathtaking image of Comet ISON, streaking through space, using a SBIG STX16803 charge-coupled device camera, fitted with a Schulman Telescope. The image was taken at Mount Lemmon from the University of Arizona’s SkyCenter, during the early hours of Oct. 8, and shows the comet’s tail illuminated in a beautiful blaze of green.
The new image was sent to Space.com, revealing the comet to be intact, disproving previous theories that the illustrious celestial body might have already started to disintegrate. Since the comet is largely composed of fragile deposits of ice, dust and small rocky particulate, the fear is that ISON will burn up before reaching perihelion, at which point it will be at its closest distance from the sun (730,000 miles).
Comet ISON Breaking Apart?
Recently detected light signatures emitted from Comet ISON, also dubbed the “Christmas Comet,” seemed to suggest the structure could break apart prior to its Nov. 28 solar approach. Ignacio Ferrin, an astrophysicist at the University of Antioquia in Medellin, Colombia, had this to say:
“This disintegration will take place before it reaches perihelion… There are also predictions for disintegration at perihelion. But based on the evidence, the comet will not get there.”
Ordinarily, a comet will begin to burn more intensely as it crosses a specific temperature threshold near the sun. The extreme temperatures cause the icy surfaces of its nucleus to evaporate, depositing water vapor and dust, as it is subjected to great thermal pressures.
Some sungrazers are large enough to survive several perihelion passages. For example, Halley’s Comet has survived numerous passages, protected by a crust of silicates and carbon structures that provide insulation from the blistering heat.
On the other hand, smaller comets frequently fracture and disintegrate, due to strong tidal forces and high temperatures. Duncan Steele, an astronomer at Armagh Observatory in Northern Ireland, explains that Comet ISON does not possess any such protection. As a consequence, the internal gases will begin to swell, exerting enormous pressure on the delicate cosmic snowball.
Ferrin suggested that ISON’s light curve began to slow, eventually reaching a plateau, and failed to demonstrate any increase in brightness.
Hubble Space Telescope Finds ISON Alive
Meanwhile, images taken by the Hubble Space Telescope on Oct. 9, 2013, also provided evidence that Comet ISON remains alive. The image shows the comet continuing with its
journey, hurtling 47,000 miles per hour towards the sun. The comet’s coma, enveloping the nucleus, is smooth and symmetrical, a find that indicates the comet is still fully intact. According to NASA officials, the absence of small fragments of debris, breaking off from the comet’s reverse, shows that its nucleus is in better health than some experts previously conjectured.
The image was taken whilst ISON was within the orbit of Mars, some 177 million miles from Earth. Much to the relief of avid stargazers, the integrity of the comet’s nucleus appears to be holding together.
Comet ISON was originally discovered by a pair of Russian astronomers, and was named after the ISON (International Scientific Optical Network) telescope. The comet is believed to have originated from the vastness of the Oort Cloud, harboring billions of icy planetesimals at the edge of our Solar System.
Space.com also has a number of other spectacular photographs submitted by a great many astronomers, and are all certainly well worth a look.
By: James Fenner