2,000ft Halloween asteroid 2015 TB145
Up-close view of Halloween asteroid 2015 TB145 provides new details, says NasaNASA/JPL-Caltech/GSSR/NRAO/AUI/NSF

Nasa has released new close-up shots of asteroid 2015 TB145 that safely flew past Earth on Halloween on 31 October. A set of eight radar images provides new insights into the asteroid.

The pictures reveal that the asteroid, famously dubbed as Halloween asteroid, is spherical in shape and approximately 2,000ft (600m) in diameter, the space agency said in a statement. Astronomers have noticed bright spots on the surface of asteroid that could be boulders.

"The radar images of asteroid 2015 TB145 show portions of the surface not seen previously and reveal pronounced concavities, bright spots that might be boulders, and other complex features that could be ridges," said Nasa's asteroid radar research programme leader, Lance Benner.

Benner said the radar images looked significantly different from those taken on the eve of Halloween on 30 October. The images are "probably the result of seeing the asteroid from a different perspective in its three-hour rotation period", he said. According to Nasa, the radar images were taken when the asteroid was between 440,000 miles (710,000 km) and about 430,000 miles (690,000 km) distant.

Asteroid 2015 TB145 safely flew past Earth on 31 October at 10am PDT (1 pm EDT and 7pm BST) when it made its closest approach to Earth. At flyby, the Halloween asteroid was 1.3 times (300,000 miles or 480,000 km) farther away from Earth than the Moon.

"The next time that asteroid 2015 TB145 will be in Earth's neighbourhood will be in September 2018, when it will make a distant pass at about 24 million miles (38 million km), or about a quarter the distance between Earth and the sun," the agency said.