Comet makes a pit stop near Jupiter’s asteroids

The unexpected guest probably won’t stay among the asteroids for long. Computer simulations show that it will have another close encounter with Jupiter in about another two years. The huge planet will tear the comet out of the system and continue its journey into the inner solar system.

“The good thing is that you are actually capturing Jupiter by launching this object and changing its orbital behavior and taking it into the internal system,” said team member Carey Lisse of the Johns Hopkins University Applied Physics Laboratory (APL) in Laurel, Maryland. . . “Jupiter controls what happens to comets once they enter the internal system by altering their orbits.”

The icy intruder is most likely one of the last members of the so-called “cube brigade” of comets to be expelled from its icy home in the Kuiper Belt and into the giant planet region through interactions with another Kuiper Belt object. . Located beyond the orbit of Neptune, the Kuiper Belt is a haven of icy debris left over from the construction of our planets 4.6 billion years ago, containing millions of objects, and occasionally these objects have near misses or collisions that alter drastically their orbits from the Kuiper Belt inward. in the region of the giant planet.

The Frozen Relic Brigade endures a bumpy ride during their journey into the sun. They gravitationally bounce from one outer planet to the next in a celestial pinball game before reaching the inner solar system, heating up as they get closer to the Sun. Researchers say objects spend as much time or even longer around giant planets that they are pulling them gravitationally, about 5 million years ago, than crossing into the internal system where we live.

“Comets in the internal ‘short period’ system break about once a century,” Lisse explained. “So to maintain the number of local kites that we see today, we think the bucket brigade has to launch a new short-period kite about once every 100 years.”

An early bloom

Seeing degassing activity on a comet 465 million miles away from the Sun (where the intensity of sunlight is 1/25 that of Earth) surprised the researchers. “We were intrigued to see that the comet had just started to activate for the first time so far from the Sun at distances where the water ice is just beginning to sublimate,” Bolin said.

Water remains frozen in a comet until it reaches about 200 million miles from the Sun, where the heat from sunlight converts the water ice into gas that escapes from the nucleus in jets. So the activity indicates that the tail might not be made of water. In fact, Spitzer’s observations indicated the presence of carbon monoxide and carbon dioxide gas, which could be driving the creation of the tail and jets seen on the comet in orbit around Jupiter. These volatiles don’t need a lot of sunlight to heat up their frozen form and turn them into gas.

Once the comet is ejected from the orbit of Jupiter and continues its journey, it may meet the giant planet again. “Short-period comets like LD2 find their fate by being thrown into the Sun and completely disintegrating, hitting a planet, or venturing too close to Jupiter once more and being ejected from the solar system, which is the usual fate,” he said. Lisse. . “The simulations show that in about 500,000 years, there is a 90% chance that this object will be ejected from the solar system and become an interstellar comet.”

The Hubble Space Telescope is an international cooperation project between NASA and ESA (European Space Agency). NASA’s Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore, Maryland, conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy, in Washington, D.C. NASA’s Jet Propulsion Laboratory, a division of Caltech in Pasadena, California, managed the Spitzer mission for the Science Mission Directorate NASA in Washington, DC Science operations were conducted at the Spitzer Science Center at IPAC at Caltech. The complete Spitzer science catalog is available through the Spitzer data archive, located in the Infrared Science Archive at IPAC. The spacecraft’s operations were based at Lockheed Martin Space in Littleton, Colorado.

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