Saturday, December 30, 2017

Newly Discovered Small Asteroid Passes by Earth

Credit: NASA

A newly detected small asteroid, known as 2017 YZ4, flew by the Earth on Thursday, December 28 at 16:50 UTC. The space rock passed by our planet at a distance of about 0.58 lunar distances (LD), what corresponds to 223,000 kilometers.

2017 YZ4 was discovered on December 25 by the Mount Lemmon Survey (MLS), which utilizes a 1.52 m cassegrain reflector telescope at Mount Lemmon Observatory in Arizona. MLS is one of the most prolific surveys when it comes to discovering near-Earth objects (NEOs). So far, it has detected more than 50,000 minor planets.

According to astronomers, 2017 YZ4 is an Apollo-type near-Earth object (NEO) with an estimated diameter between 4 and 14 meters. It has an absolute magnitude of 28.1 and orbits the sun every 1.74 years at a distance of 1.45 AU. On Thursday, it whizzed by our planet with a relative velocity of 9.6 km/s.

Besides flying past Earth on December 28, 2017, YZ4 also flew by Moon on the same day at a distance of approximately 0.68 LD, or 261,000 kilometers. Next close approach of this asteroid to Earth is expected on May 22, 2018, when it will pass at 182 LD (70 million kilometers).

On December 30, there were 1,872 Potentially Hazardous Asteroids (PHAs) detected, however none of them is on a collision course with our planet. PHAs are asteroids larger than 100 meters that can come closer to Earth than 19.5 LD.

To date, astronomers have discovered more than 17,500 NEOs. Only this year, nearly 2,100 such objects were detected.