P/2010 A2 ripreso da Hubble Space Telescope [ita-eng]

AGGIORNAMENTO - NEWS

L'Hubble ha ripreso l'oggetto P/2010 A2 di cui si era già sentita notizia nei giorni passati. Questo asteroide, scoperto il 6 gennaio 2010 dal Lincoln Near-Earth Asteroid Research (LINEAR), fin dall'inizio ha incuriosito gli studiosi, per la luminosa coda che mostra una misteriosa "X".
Dalle prima analisi era già emersa la possibilità che in realtà si trattasse di emissioni provenienti direttamente dal suo nucleo. 

Questa ipotesi fa pensare che di recente P/2010 A2 abbia colliso con un altro asteroide e che la coda sia la "ferita che sanguina" dopo l'urto.

Lo scontro, dovrebbe essere avvenuto ad una velocità di moto di oltre 11.000 miglia orarie, cioè ben cinque volte quella di un proiettile. Il suo nucleo è stimato in circa 160 metri. E' la prima volta in assoluto, che si osserva una coda di emissioni  di polveri da un oggetto non cometario. 

Ricordiamo che questo asteroide non è pericoloso per la Terra e dista ben 145 milioni di km.

Tuttavia lo studio in corso ci rivela come nella fascia Principale degli asteroidi, le collisioni siano ancora frequenti e che non è cosa rara che in seguito a tali eventi, alcuni grossi frammenti mutino l'orbita fino ad avvicinarsi anche di molto al nostro pianeta.

Vi propongo questo video correlato, molto interessante sui NEO, gli asteroidi potenzialmente pericolosi:

articolo correlato: http://nemsisprojectresearch.blogspot.com/2010/01/impatto-tra-asteroidi.html




English
Slam! Two Asteroids Suspected in Space Collision
By SPACE.com Staff
posted: 02 February 2010
12:10 pm ET

A mysterious trail of debris spotted in space suggests two asteroids recently slammed into each other.
Though such space rock collisions are thought to be common, direct evidence of the cosmic smashups has never been seen before. New images from NASA's Hubble Space Telescope, however, have caught the suspected collision on camera.
An X-shaped debris pattern was observed by Hubble on Jan. 25 and 29. The pictures, released today, show a comet-like object, dubbed P/2010 A2, with the X-pattern of filamentary structures near the nucleus.
"This is quite different from the smooth dust envelopes of normal comets," said study leader David Jewitt of the University of California at Los Angeles. "The filaments are made of dust and gravel, presumably recently thrown out of the nucleus. Some are swept back by radiation pressure from sunlight to create straight dust streaks. Embedded in the filaments are co-moving blobs of dust that likely originated from tiny unseen parent bodies."
The two asteroids likely smashed into each other with an average impact speed of more than 11,000 miles per hour, or five times faster than a rifle bullet.
The Hubble photos show that the main nucleus of P/2010 A2 lies outside its own halo of dust. This pattern has never been seen before in a comet-like object. The nucleus is estimated to be about 460 feet (140 meters) in diameter.
Scientists think this nucleus is the surviving remnant of the collision, and the tail is the rubble left over from the crash.
"If this interpretation is correct, two small and previously unknown asteroids recently collided, creating a shower of debris that is being swept back into a tail from the collision site by the pressure of sunlight," Jewitt said.
P/2010 A2 orbits in the warm, inner regions of the asteroid belt between Mars and Jupiter. When the object was observed, it was approximately 180 million miles (290 million km) from the sun and 90 million miles (145 million km) from Earth.
The Hubble images were captured by its new Wide Field Camera 3, which was installed during the May 2009 space shuttle servicing trip. The camera can spot house-sized fragments at the distance of the asteroid belt.

Link:  
http://www.space.com/scienceastronomy/asteroid-collision-hubble-100202.html
http://hubblesite.org/newscenter/archive/releases/2010/07/image/d/

Adattamento e traduzione a cura di Arthur McPaul