The asteroids Ryugu and Bennu which orbit between Earth and Mars formed after a much larger rock was split apart, scientists have claimed.
Mathematical modelling suggests the pair – measuring 3,280-foot and 1,610-foot in diameter – formed after two centres of gravity were created.
But rock pulled from both will need to be tested to confirm the theory.
Samples from Ryugu are already onboard Japan‘s Hayabusa2 spacecraft and expected to touchdown on Earth in late 2020.
And NASA’s OSIRIS-REx is scheduled to land on its suspected-sister by October 20, to collect further samples which will also be flown to Earth.
Mathematical modelling revealed Ryugu (left) and Bennu (right) may have formed from a larger asteroid that broke apart
The model showed after an asteroid shattered its pieces came together at two points
It was based on observations of asteroids in the Mars-Jupiter belt, where Bennu and Ryugu may have originated
Astronomers at the University of Arizona and Laboratoire Lagrange, Ivory Coast, modelled collisions in the Mars-Jupiter asteroid belt before making the proposal.
Their study, published in Nature Communications, showed fragments are ejected but then re-accumulate into a spinning-top shape – like that of both asteroids.
They also noted a difference in hydration between the possible-siblings, but said this did not discount the proposed relationship.
The team hopes to be able to measure the composition and age of formation of the samples from both asteroids to confirm their theory.
OSIRIS-REx has beamed images of Bennu’s rocky surface back to Earth, revealing the barren lunar surface.
The pictures show its chosen landing site – dubbed ‘Nightingale’ – which is located in a crater high up the asteroids northern hemisphere.
The spacecraft will cut chunks 0.8 inches in diameter from the asteroid before beginning the journey home.
NASA has sent pictures of Bennu back to Earth. The image above shows the proposed landing site on the asteroid for its spacecraft OSIRIS-REx
OSIRIS-REx will collect small (less than 0.8 inches in diameter) rocks from the surface before beginning the journey back to Earth. (Artists impression)
Hayabusa2, not to be outdone, sent images of Ryugu’s lunar-surface back to Earth in February.
Its pictures revealed reddening in some of the rocks, leading scientists at the University of Tokyo to conclude that it once passed much closer to the sun.
‘Immediately after touchdown, Hayabusa2’s thrusters disturbed dark, fine grains that originate from the redder materials,’ wrote planetary scientist Tomokatsu Morota of the University of Tokyo and colleagues in their paper,
‘The stratigraphic relationship between identified craters and the redder material indicates that surface reddening occurred over a short period of time.’
‘We suggest that Ryugu previously experienced an orbital excursion near the Sun.’
Japan’s Hayabusa2 spacecraft has captured this picture of Ryugu’s surface. It revealed reddened rocks, which suggests at one point the asteroid may have passed near the Sun
Scientific number: 162173
Discovery date: 10 May 1999 by astronomers in Socorro, New Mexico
Name: It refers to a magical underwater palace in Japanese folklore
Size: 3,280-foot in diameter
Orbit: Around the sun between Earth and Mars once every 16 months
Danger to Earth: Not at present
Visit description: Hayabusa2 arrived in June 2018. It has now left and is returning to Earth
Scientific number: 101955
Discovery date: 11 September 1999 by astronomers in Socorro, New Mexico
Name: Bird in Egyptian myth linked to the sun, creation and re-birth
Size: 1,610-foot in diameter
Orbit: Around the sun between Earth and Mars
Danger to Earth?: Yes. Crosses our planet’s orbit. Eight potential Earth impacts are predicted between 2169 and 2199. It will pass near Earth in 2060.
Visits planned?: Yes. OSIRIS-REx is expected to touch down this month.
Source: Daily Mail – Articles