Published: Thu, July 11, 2019
Research | By Raquel Erickson

How This Huge, Superfast Asteroid Stayed Hidden in Near-Earth Orbit

How This Huge, Superfast Asteroid Stayed Hidden in Near-Earth Orbit

"Thirty years in the past, individuals began organizing methodical asteroid searches, discovering bigger objects first, however now that nearly all of them have been discovered, the larger ones are uncommon birds", Tom Price of Caltech describes.

"You don't find kilometer-size asteroids very often these days", said Quanzhi Ye, a postdoctoral scholar at Caltech who discovered 2019 LF6 via the Zwicky Transient Facility, a camera at the school's Palomar Observatory that scans the sky for objects.

The newly discovered kilometre-sized asteroid dubbed 2019 LF6 has the shortest solar year around our Sun - compared to all the other space rocks found floating around the Solar System at just 151 days.

A team of astronomers led by Quanzhi Ye from Caltech University in the USA found 2019 LF6 using the Zwicky Transient Facility (ZTF) at the Palomar Observatory in California, as noted in a press release. In other words, 2019 LF6's aphelion (farthest distance from the Sun) is still shorter than Earth's perihelion (closest distance to the Sun).

The space rock is an interior-Earth object, or Atira asteroid, one of 20 asteroids that orbit the sun inside Earth's orbit.


A massive asteroid has eluded astronomers because of its unusual orbit - until now. The camera scans the skies rapidly making it well-suited for finding Atira asteroids with short observing windows.

'We only have about 20 to 30 minutes before sunrise or after sunset to find these asteroids, ' says Ye.

"Both of the large Atira asteroids that were found by ZTF orbit well outside the plane of the Solar System", said Caltech Professor Tom Prince, a member of the ZTF team. The ZTF is responsible for scanning the skies for transient objects that can be anything from exploding stars to asteroids and, because it's capable of scanning the sky quite fast, it's flawless for finding the "Atira" asteroids, which usually only have 20 to 30-minute observation windows. "This means that sometime prior to now, they have been flung out of the plane of the solar system as a result of they came too close to Venus or Mercury". Both of the objects orbit basically perpendicular to the essentially flat plane of the solar system that the planets inhabit. NEOCam would pick up the infrared, or heat, signatures of asteroids.

ZTF is funded by the National Science Foundationand an worldwide collaboration of partners. NASA supports ZTF's search for near-Earth objects through the Near-Earth Object Observations program.

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