Hubble Space Telescope Offers a Closer Look at Comet ISON

NASA's Hubble Space Telescope has offered astronomers their clearest view yet of Comet ISON, which is a recently-discovered sun grazer comet that may light up the sky later this year, or come so close to the Sun that it disintegrates.

A University of Maryland-led research team is closely following ISON, which offers a rare opportunity to witness a comet's evolution as it makes its first-ever journey through the inner solar system.

"Like all comets, ISON is a 'dirty snowball' - a clump of frozen gases mixed with dust, formed in a distant reach of the solar system, traveling on an orbit influenced by the gravitational pull of the Sun and its planets," explained Maryland assistant research scientist Michael S. Kelley. "ISON's orbit will bring it to a perihelion, or maximum approach to the Sun, of 700,000 miles on November 28.

Comet ISON was discovered by amateur astronomers in September 2012, Comet ISON is about to reach the outer edge of the asteroid belt, located some 280 million miles from Earth, said William Cooke, lead scientist at NASA's Meteoroid Environment Office at the Marshall Space Flight Center in Huntsville, Alabama.

"We want to look for the ratio of the three dominant ices, water, frozen carbon monoxide, and frozen carbon dioxide, or dry ice," said Maryland astronomy Prof. Michael A'Hearn. "That can tell us the temperature at which the comet formed, and with that temperature, we can then say where in the solar system it formed."

According to the report,the Maryland team will use both the Hubble Space Telescope and the instruments on the Deep Impact spacecraft to continue to follow ISON as it travels toward its November close up (perihelion) with the sun.