NASA ’s OSIRIS - REx is getting quick to touchdown onasteroid Bennu next monthand the team has just released some more brainwave into the asteroid . Researchers account that Bennu is suffer pieces of rocks into space at a higher rate than expected .
In a series of document published in theJournal of Geophysical Research : Planets , the OSIRIS - REx team studying Bennu describes the release of these atom , what make them , and how they ’ve been using them to translate Bennu in greater detail .
The team tracked 100 of ejected corpuscle and they have a bit of a secret on their hands . The size of the particles matches what is expected to break away from an asteroid like Bennu due to thermal fracturing . The asteroid rotates on its axis in just over four hours , so its airfoil decease from hot to cold promptly , cracking its rocks . However , the localisation of the expulsion events meet a model that go through these releases being down to the shock of micrometeor on the surface of Bennu . investigator are unsure which is the rightful cause . perhaps it ’s a combination of both .
But that ’s is not all . The particles have also helped the team study the extremely weak gravitational puff of the asteroid . They move far nearer to Bennu than it would be safe for OSIRIS - REx so can provide a more accurate account of the asteroid ’s irregular gravity .
" The speck were an unexpected gift for gravity skill at Bennu since they allowed us to see tiny magnetic declination in the asteroid ’s gravity field that we would not have known about otherwise , " enjoin the confidential information author of one of the papers Steve Chesley , from NASA ’s Jet Propulsion Laboratory , in astatement .
These pieces of rocks are roughly 7 mm ( 0.25 inches ) across . The squad reports how some are flip into place and come back down before long , others ride out around in orbit for a few days , others hop across the aerofoil , and some are just lost into space .
" We retrieve that Bennu ’s bowlder - cover surface was the dotty card discovery at the asteroid , but these particle events emphatically surprised us , " allege Dante Lauretta , the OSIRIS - king main investigator and a professor at the University of Arizona . " We ’ve expend the last year investigating Bennu ’s active surface , and it ’s provided us with a noteworthy opportunity to dilate our noesis of how combat-ready asteroid behave . "
OSIRIS - REx is expect to fly down to the surface of Bennu onOctober 20to gather up a sample . It will then return to Earth on September 24 , 2023 , making it the third spacecraft ever to bring a sample distribution of an asteroid home .
