Wayward Comet makes a temporary stop near Jupiter’s Asteroids

Comet emerges from the cold and finds an exit on its solar journey

Long journeys can be tedious and tedious. Therefore, many travelers break up their arduous journey by making rest stops along the way.

Astronomers have found that at least one orbiting comet does the same. The wayward object made a temporary stop near the giant Jupiter. The icy visitor has a lot of company: it settled near the family of captured asteroids known as Trojans orbiting the Sun with Jupiter.

This is the first time a comet-like object has been spotted near the Trojan asteroid population. Hubble Space Telescope observations show that the orbiter shows signs of the transition from an icy asteroid-like body to an active comet, which germinates a long tail, protrudes rays of material and is shrouded in a coma of dust and gas.

The intermediary came from the icy outskirts of our solar system, a comet nest called the Kuiper Belt. This nomad was probably snapped up by Jupiter’s powerful gravity after having a brush with the giant planet.

Jupiter’s uninvited guest will probably not hang around the planet for very long. As the “bouncer” of the solar system, the gravitational pull of the monster planet will eventually recharge the comet after its journey to our sun.

For the first time, a quirky comet-like object was spotted near the family of ancient asteroids.

After traveling several billion miles to the sun, a young, comet-like object orbiting the giant planets found a temporary parking space. The object settled near a family of captured ancient asteroids, called Trojans, orbiting the Sun along Jupiter. This is the first time a comet-like object has been spotted near the Trojan population.

The unexpected visitor belongs to a class of icy bodies living in the space between Jupiter and Neptune. They are called Centaurs and become active for the first time when heated as they approach the sun, and dynamically change into more comet-like.

Visible light photos by NASAThe Hubble Space Telescope shows that the vagabond object shows signs of comet activity, such as a tail, which radiates in the form of jets and an envelope of dust and gas. Earlier observations by NASA’s Spitzer Space Telescope provided clues to the composition of the comet-like object and the gases that propelled its activity.

“Only Hubble could detect active comet-like features in such great detail, and the images clearly show these features, such as a broad tail of about 400,000 miles and high resolution near the core due to a coma and rays,” Bryce said. Bolin, principal investigator at Caltech in Pasadena, California, said.

Commenting on capturing Centaur as a rare event, Bolin added: ‘The visitor must have entered Jupiter’s orbit at the right orbit to have a kind of configuration that gives it the appearance of sharing its orbit with the planet. We investigate how it was captured by Jupiter and ended up under the Trojans. But we think it may be related to the fact that it had a somewhat close encounter with Jupiter. ‘

The team’s minutes appear in the issue of 11 February 2021 The Astronomical Journal.

The research team’s computer simulations show that the icy object, named P / 2019 LD2 (LD2), probably swung near Jupiter about two years ago. The planet then pulled the stray visitor to the Trojan asteroid group’s co-orbital location heavily, leading Jupiter about 437 million miles.

Bucket Brigade

The nomadic object was discovered in early June 2019 by the ATLAS telescopes of the Asteroid Asteroid Terrestrial Impact (ATLAS) on the extinct volcanoes, one on Mauna Kea and one on Haleakala. Japanese amateur astronomer Seiichi Yoshida suggested the Hubble team for possible comet activity. The astronomers then scan archival data from the Zwicky Transient Facility, a wide field survey conducted at the Palomar Observatory in California, realizing that from April 2019 the object was clearly active in images.

They followed up with observations from the Apache Point Observatory in New Mexico, which also hinted at activity. The team observed the comet with the help of Spitzer a few days before the observatory’s retirement in January 2020 and identified gas and dust around the comet’s core. These observations convinced the team to use Hubble to take a closer look. Aided by Hubble’s sharp vision, the researchers identified the tail, coma structure, size of the dust particles and their ejection velocity. These images helped them confirm that the features were due to relatively new comet-like activities.

Although the location of LD2 is surprising, Bolin wonders if this pit stop could be a common attraction for some comets bound by the sun. “It could be part of our solar system through the Jupiter Trojans to the inner solar system,” he said.

The unexpected gas will probably not stay between the asteroids for very long. Computer simulations show that it will have another close encounter with Jupiter in two years. The solid planet will pick up the comet from the system, and it will continue its journey to the inner solar system.

“The coolest thing is that you actually catch Jupiter to throw this object around and to change its orbital behavior and bring it to the inner system,” said team member Carey Lisse of the Johns Hopkins University Applied Physics Laboratory (APL) in Laurel , Maryland, said. . “Jupiter controls what goes on with comets as soon as they end up in the inner system by changing their orbits.”

The icy intermediary is most likely one of the youngest members of the so-called “bucket brigade” comets kicked out of its icy house in the Kuiper Belt and into the giant planetary region by interactions with another object of the Kuiper Belt. The Kuiper Belt is past the orbit of Neptune and is a refuge of icy, residual debris from the construction of our planets, 4.6 billion years ago, with millions of objects. Sometimes these objects almost miss or collisions that drastically change their orbits from the Kuiper belt inward into the giant planetary region.

The bucket brigade of icy remains endures a bumpy ride during their journey to the sun. They bounce gravely from one planet to the next in a game of celestial pinball before reaching the inner solar system, and they are warmed up as they get closer to the sun. According to the researchers, the objects spend as much or even more time around the giant planets, which draw gravity on them – about 5 million years – than they cross in the inner system where we live.

“Comets from the ‘transient’ inner system break up about once a century,” Lisse explained. “To maintain the number of local comets we see today, we think the bucket brigade should deliver a new comet about once every 100 years.”

An early bloom

To see researchers how degassing activities on a comet come 465 million miles from the sun (where the intensity of sunlight is 1 / 25th as strong as on Earth). “We were intrigued to see that the comet for the first time so far from the sun began to become active at distances where the ice was barely beginning to sublimate,” Bolin said.

Water remains frozen on a comet until it reaches about 200 million miles from the sun, where heat from sunlight converts water ice into gas escaping from the core in the form of rays. The activity therefore indicates that the tail may not have been made of water. In fact, observations by Spitzer indicated the presence of carbon monoxide and carbon dioxide gas, which could drive the creation of the tail and rays orbiting Jupiter’s comet. These volatiles do not need much sunlight to heat their frozen form and convert it into gas.

Once the comet is kicked out of Jupiter’s orbit and continues its journey, it can meet the giant planet again. “Comets as short periods as LD2 meet their fate by throwing into the sun and completely disintegrating, hitting a planet, or once again venturing too close to Jupiter and throwing out of the solar system, which is the usual fate, said Lisse. . “Simulations show that in about 500,000 years there is a probability that this object will become out of the solar system and become an interstellar comet.”

Reference: “Initial characterization of Active Transitioning Centaur, P / 2019 LD₂ (ATLAS), using Hubble, Spitzer, ZTF, Keck, Apache Point Observatory, and GROWTH Visible and Infrared Imaging and Spectroscopy ”by Bryce T. Bolin, Yanga R. Fernandez, Carey M. Lisse, Timothy R. Holt, Zhong- Yi Lin, Josiah N. Purdum, Kunal P. Deshmukh, James M. Bauer, Eric C. Bellm, Dennis Bodewits, Kevin B. Burdge, Sean J. Carey, Chris M. Copperwheat, George Helou, Anna YQ Ho, Jonathan Horner , Jan van Roestel, Varun Bhalerao, Chan-Kao Chang, Christine Chen, Chen-Yen Hsu, Wing-Huen Ip, Mansi M. Kasliwal, Frank J. Masci, Chow-Choong Ngeow, Robert Quimby, Rick Burruss, Michael Coughlin, Richard Dekany, Alexandre Delacroix, Andrew Drake, Dmitry A. Duev, Matthew Graham, David Hale, Thomas Kupfer, Russ R. Laher, Ashish Mahabal, Przemyslaw J. Mróz, James D. Neill, Reed Riddle, Hector Rodriguez, Roger M. Smith, Maayane T. Soumagnac, Richard Walters, Lin Yan and Jeffry Zolkower, 11 February 2021, The Astronomical Journal.
DOI: 10.3847 / 1538-3881 / abd94b

The Hubble Space Telescope is a project of international collaboration between NASA and ESA (European Space Agency). NASA’s Goddard Space Flight Center in Greenbelt, Maryland, controls the telescope. The Space Telescope Science Institute (STScI) in Baltimore, Maryland, conducts scientific operations of Hubble. STScI is operated for NASA by the Association of Universities for Research in Astronomy, in Washington, DC NASA’s Jet Propulsion Laboratory, a division of Caltech in Pasadena, California, has the Spitzer mission for NASA’s Directorate Science Mission in Washington, DC , management. at the Spitzer Science Center at IPAC at Caltech. Spitzer’s entire science catalog is available via the Spitzer Data Archive, housed in the Infrared Science Archive at IPAC. Spacecraft operations were based at Lockheed Martin Space in Littleton, Colorado.