They all found out that 2017 YE5 was actually a pair of pieces of rock, which circled each other every 20-24 hours. They each have their own unique structure and properties. Scientists initially noticed what they thought were two lobes, but a closer look showed a gap between the distinct parts.
The new observations allowed to detect that the outdoor a year ago, the asteroid is actually made up of two rotating around each other are the same object.
The same situation goes for a system like Didymos, where a very large asteroid has a much smaller one orbiting it. But coming across a binary consisting of two similar-sized objects is much more rare.
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.
The announcement came yesterday from NASA, which observed this exotic pair with its Goldstone Solar System Radar (GSSR) in California and uncovered that asteroid 2017 YE5 is even more special than we imagined.
Calculations revealed that the asteroid would make its closest approach to Earth for the next 170 years in June. But with some time, the researchers were able to witness an orbital rotation that revealed a clear void between the objects.
Then the Arecibo Observatory in Puerto Rico and the Green Bank Observatory in West Virginia did something unbelievable: using a technique called "bi-static radar configuration" Arecibo broadcasted a radar signal to detect 2017 YE5, which Green Bank then received.
Are those twins? That's how astronomers reacted a month ago when they studied an asteroid called 2017 YE5. Arecibo bounced its radar signal off the object and Green Bank recorded the return signal.
Its dual nature wasn't the only unusual attribute to come to light, either. Astronomers can use those received signals to paint a picture of the shape of an asteroid. However, radar imaging showed that the duo is darker in color and reflects less sunlight than typical asteroids, making it larger than its optical brightness lets on. They saw two objects which orbited each other! Different levels of reflectivity suggests the two rocks feature different densities and compositions.
In addition to the resources NASA puts into understanding asteroids, the PDCO also partners with other USA government agencies, university-based astronomers, and space science institutes across the country, often with grants, interagency transfers and other contracts from NASA.
The video below discusses 2017 YE5.