Strange double asteroid discovered by world largest radio telescope: NASA
New Delhi : The world’s largest radio telescope reveals that an asteroid discovered last year is actually two objects, each about 900 metres in size and orbiting each other. Scientist discovered the asteroid 2017 YE5 with observations provided by the Morocco Oukaimeden Sky Survey in December last year. But, they were unknown about the physical properties of asteroid until the end of June, NASA mentioned in a statement.
Astronauts say that it is only the fourth "equal mass" binary near-Earth asteroid ever detected, consisting of two objects nearly identical in size, orbiting each other.
Now, the new observations by the radio telescope gave detailed images ever obtained of this type of binary asteroid, according to the US space agency.
On June 21, the asteroid 2017 YE5 made its closest approach to Earth for at least the next 170 years, coming to within six million kilometers of Earth, or about 16 times the distance between Earth and the Moon.
On June 21 and 22, observations by NASA's Goldstone Solar System Radar (GSSR) in California showed the first signs that 2017 YE5 could be a binary system.
The observations clarified two distinct lobes, but the orientation of the asteroid was positioned in such a way that scientists could not observe if the two bodies were separate or joined.
The only thing captured was that the two objects rotate at a distinct gap between them.
Scientists at the Arecibo Observatory in Puerto Rico teamed up with researchers at the Green Bank Observatory (GBO) in West Virginia to confirm that 2017 YE5 consists of two separated objects.
The new observations obtained between June 21 and 26 highlights that the two objects revolve around each other once every 20 to 24 hours.
Images captured by the Radar shows that the two objects are larger than their combined optical brightness originally suggested, indicating that the two rocks do not reflect as much sunlight as a typical rocky asteroid. 2017 YE5 is likely as dark as charcoal, NASA said.
The Goldstone images taken on June 21 also show a remarkable difference in the radar reflectivity of the two objects, a phenomenon not seen previously among more than 50 other binary asteroid systems studied by radar since 2000.
Scientists say that among near-Earth asteroids larger than 200 metres in size, about 15 per cent are binaries with one larger object and a much smaller satellite. Equal-mass binaries like 2017 YE5 are extra-ordinary.