Ison Comet records a burst of activity and becomes visible - The País.com (Spain)

Ison

comet, discovered more than a year, is being observed by astronomers around the world as it nears the Sun And surprised to experience a burst of activity “that has greatly increased both its production gas as its brightness, to the point of doing observable to the naked eye, “according to experts at the Institute of Astrophysics of Andalusia (IAA), the CSIC. The object, in its orbit, reach the point of closest approach to the Sun on November 28, when it will be only 2.7 times the radius of the star (1.8 million kilometers), almost “saved in the Sun” astronomers say. Reach temperatures of about 5,000 degrees Celsius and can then increase its brightness by releasing huge amounts of dust, or it may be fragmented and vaporized due to tidal forces and heat of the star, as has happened more than two thousand known kites. Scientists are very outstanding.

For now, the Ison has already surprised with the sudden increase of activity: there has been an increase of about 15 times the sublimation of hydrocyanic acid in just 48 hours, as reported by the researcher Pablo Santos Sanz, the IAA , which is involved in a campaign of observations of the comet with the IRAM telescope, 30 meters in diameter. “Several sources also point to an increase in water sublimation,” the IAA.

“One possible explanation for the outbreak is that the axis of rotation [the comet] has been quite aligned with the direction to the Sun, so that only one hemisphere of the comet nucleus has had radiation, and can have fresh ice , in the other hemisphere, which just received sunlight until now, “explains José Luis Ortiz, a researcher at IAA. “As the Ison gets closer to the Sun will change also the position of the subsolar point on the comet and, therefore, there will be parts that suddenly receive radiation and can sublimate.”

Comets IAA remind researchers are frozen solid suffering dramatic changes as it approaches the Sun With increasing temperature the ice is heated, evaporate (sublimate) and carry with dust grains, to be free reflect sunlight and they form the tail and coma or diffuse spot that wraps the core center. Moreover, as has happened now to Ison, may intensify its brightness suddenly.

Ison was discovered on September 21 last year by Russian astronomers. According to the calculations of its orbit, comes from the Oort cloud, “a bubble that surrounds the Solar System and are believed to consists of the remains of the nebula that gave rise to the sun and planets 4,600 million years ago .