THE FOREST, Texas — Like the “Peanuts” character Pigpen, the near-Earth asteroid Bennu relocations around in a cloud of its own dust.

NASA’s OSIRIS-REx spacecraft has actually seen Bennu spit out plumes of dust 11 times because the spacecraft got to the asteroid in December2018 And a few of that dust is captured in orbit around the asteroid, researchers revealed March 19 at the Lunar and Planetary Science Conference. It’s the very first time astronomers have actually found such activity at an asteroid.

” Absolutely we did not anticipate to see this,” stated OSIRIS-REx primary private investigator Dante Lauretta of the University of Arizona in Tucson. “We are most likely seeing a brand-new sort of activity at asteroid Bennu.”

While this outcome has actually planetary researchers delighted, the total news from Bennu is combined. OSIRIS-REx’s main objective is to gather dust from the asteroid in 2020 and bring it back to Earth in 2023, in hopes that the rubbly, water-rich asteroid holds hints to the origin of life in the planetary system( SN: 1/19/19, p. 20). However that task might show challenging. In a series of research studies in Nature journals launched March 19, the OSIRIS-REx group reports that the area rock is a minefield of stones much larger than the craft was created to browse.

"the gargoyle" got to the near-Earth asteroid on December 3, when the rock had to do with130 million kilometers far from Earth( SN Online:12/ 3/18). To the group’s surprise, OSIRIS-REx’s navigation cams got a number of intense areas drifting near the asteroid on January 6.

Examining the areas exposed that they were eruptions of dust particles from Bennu’s surface area. The particles were ejected at speeds in between a couple of centimeters per 2nd and 3 meters per second. A few of the dust is flying off into area, however some is getting captured in orbit around Bennu, Lauretta stated. The group saw11 different plumes from January 6 to February18

” I’m surprised,” states planetary researcher William McKinnon of Washington University in St. Louis, who is not part of the OSIRIS-REx group.” I have actually never ever become aware of this prior to. That’s the coolest thing up until now.”

Lauretta and associates aren’t sure what triggers the plumes. One concept is that Bennu’s subsurface includes unpredictable gases, which leave from the rock as the sun warms them up and press out plumes of dust while doing so. If so, Bennu might have reached near-Earth area reasonably just recently, though it’s uncertain precisely when. Due to the fact that the asteroid was most likely born even more from the sun in the asteroid belt in between Mars and Jupiter, it most likely would have lost those volatiles had it roamed into the inner planetary system a long period of time back, the researchers state.

The group does not believe that the dust presents a risk to the spacecraft. However Bennu’s surface area might.

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The strategy was for the craft to briefly land in an area a minimum of 50 meters broad, where a vacuumlike instrument would gather dust no bigger than 2 centimeters throughout. However there are no clear areas that are broad enough on Bennu’s surface area. The majority of the asteroid is a stone field, and the largest locations of little, sandy particles cover simply 20 meters. The group is dealing with changing its strategies to effectively get the products from a smaller sized location.

” We do have sampleable product on this asteroid,” DellaGiustina states. “It’s not a fantastic sandy asteroid loaded with these centimeter-scale particles that we were expecting, however it is a practical circumstance.”

Another asteroid sample return objective might use more hope. The Japanese Hayabusa2 objective is likewise checking out a boulder-covered asteroid, called Ryugu. And Hayabusa2 appears to have taken a sample of product on February 21( SN Online: 2/22/19). “That provides us a great deal of self-confidence,” DellaGiustina states. The OSIRIS-REx group is preparing to consult with the Hayabusa2 group to see what lessons can be found out.