Tag Archives: Near Earth Asteroids

Rare asteroid orbiting near Venus discovered

The Zwicky Transient Facility (ZTF), a new sky survey telescope whose main goal is to find Near Earth asteroids, has discovered a rare asteroid orbiting near Venus.

A state-of-the-art sky-surveying camera, the Zwicky Transient Facility, or ZTF, detected the asteroid on January 4, 2019. Designated 2019 AQ3, the object has the shortest “year” of any recorded asteroid, with an orbital period of just 165 days. It also appears to be an unusually big asteroidal specimen. “We have found an extraordinary object whose orbit barely strays beyond Venus’ orbit—that’s a big deal,” said Quanzhi Ye, a postdoctoral scholar at IPAC, a data and science center for astronomy at Caltech. Ye called 2019 AQ3 a “very rare species,” further noting that “there might be many more undiscovered asteroids out there like it.”

…The orbit, as it turns out, is angled vertically, taking 2019 AQ3 above and below the plane where the planets run their laps around the sun. Over its short year, 2019 AQ3 plunges inside of Mercury, then swings back up just outside of Venus’ orbit.

The telescope, in operation since March 2018, and so far found

nearly 60 new near-Earth asteroids. Two of these were spotted in July 2018 mere hours before they gave Earth quite a close shave. Designated 2018 NW and 2018 NX, the duo of bus-sized asteroids whipped past at a distance of about 70,000 miles, or only a third of the way to the moon. Fortunately, the newfound 2019 AQ3 poses no threat; the closest it ever comes to Earth is about 22 million miles.


Astronomers reduce estimate of still undiscovered dangerous asteroids

Astronomers have now reduced [pdf] their estimate of the number of still undiscovered dangerous Near Earth Asteroids (NEAs) that could impact the Earth from 100 to less than 40.

Observers have been cataloging potentially hazardous asteroids for decades. Based on the number of finds, the area of sky explored, and the limiting brightness our telescopes and cameras can reach, researchers can estimate what fraction of the NEA population has been detected so far and how many more objects lurk undiscovered. Harris has published numerous such estimates over the years. Recently he realized that his estimates have been plagued by a seemingly innocuous but nonetheless consequential round-off error. Once corrected, the estimated number of large (diameter > 1 kilometer) NEAs remaining to be discovered decreases from more than 100 to less than 40.

To put it mildly, there is a lot of uncertainty here. This also reminds me of the cavers’ joke question: “How many miles of unexplored passages does this cave have?”