Rare double asteroid discovered near Earth

An asteroid discovered in December 2017 is surprisingly not one asteroid, but two, each about 900 metres in size and orbiting each other, reveal new observations by three of the world’s largest radio telescopes.

Near-Earth asteroid 2017 YE5 was discovered with observations provided by the Morocco Oukaimeden Sky Survey in December 2017, but no details about the asteroid’s physical properties were known until the end of June, NASA said in a statement.

Asteroid 2017 YE5

Asteroid 2017 YE5, first spotted on December 21, 2017 made its closest approach to Earth for at least the next 170 years, coming to within six million kilometres of Earth, or about 16 times the distance between Earth and the Moon on June 21. 2017 YE5 takes 1,730 days to orbit the Sun, or 4.74 years.

What is so special about this near-Earth asteroid 2017 YE5?

Asteroid 2017 YE5 is special as each of the two asteroids measured around 900 metres, which means they’re roughly around the same size.

Asteroids come in different shapes and sizes. Smaller asteroid of the family of near-Earth asteroids orbits around the larger one. However, if both asteroids are of equal size, the two asteroids orbits around each other as the foci of their orbit sit in empty space.

2017 YE5 is only the fourth equal mass binary near-Earth asteroid ever detected, consisting of two objects nearly identical in size, orbiting each other.

The new observation showed that one half of the binary looks to be much darker than the other.

According to NASA, the new observations provide the most detailed images ever obtained of this type of binary asteroid.

NASA’s Goldstone Solar System Radar (GSSR) finds 2017 YE5 could be a binary system

The December 2017 observation by the Morocco Oukaimeden Sky Survey could find out much about the properties of 2017 YE5.

Subsequently, astronomers at NASA’s Goldstone Solar System Radar (GSSR) in California conducted a series of radar observations.

Observations by the team showed the first signs that 2017 YE5 could be a binary system, on June 21 and 22. The observations found two distinct lobes.

The observation also proved the asteroids to have a distinct gap between them.

Arecibo Observatory with Green Bank Observatory (GBO) confirm 2017 YE5 consisting of two separated objects

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 confirmed that the two objects revolve around each other every 20 to 24 hours.

“Radar imaging 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.

(With inputs from agencies)