JPL: Small Asteroid Is Earth's Constant Companion

[bystander]

Small Asteroid Is Earth's Constant Companion
NASA | JPL-Caltech | 2016 Jun 15

[c][youtube]https://www.youtube.com/watch?v=SbbAnVU4rmY[/youtube]Asteroid 2016 HO3 has an orbit around the sun that keeps it as
a constant companion of Earth. Credit: NASA/JPL-Caltech[/c][hr][/hr]

A small asteroid has been discovered in an orbit around the sun that keeps it as a constant companion of Earth, and it will remain so for centuries to come.

As it orbits the sun, this new asteroid, designated 2016 HO3, appears to circle around Earth as well. It is too distant to be considered a true satellite of our planet, but it is the best and most stable example to date of a near-Earth companion, or "quasi-satellite."

"Since 2016 HO3 loops around our planet, but never ventures very far away as we both go around the sun, we refer to it as a quasi-satellite of Earth," said Paul Chodas, manager of NASA's Center for Near-Earth Object (NEO) Studies at the Jet Propulsion Laboratory in Pasadena, California. "One other asteroid -- 2003 YN107 -- followed a similar orbital pattern for a while over 10 years ago, but it has since departed our vicinity. This new asteroid is much more locked onto us. Our calculations indicate 2016 HO3 has been a stable quasi-satellite of Earth for almost a century, and it will continue to follow this pattern as Earth's companion for centuries to come." ...

[professional beer drinker]

NASA has indicated that an asteroid 2016 HO3 is actually a second moon of the Earth. Another way of describing the object is that it is a natural satellite of the Earth-Moon binary planetary system. Wish to know whether the object is visible in the evening sky for observation from northern hemisphere. Object is thought to be about 110 meters in diameter and is probably a remnant companion of the Earth-Moon system from antiquity. Venus is also known to be orbited by a minor body of approximately 400 meters in diameter; refered to as quasi satellite 2002 VE 68.

If the orbit of 2016 HO3 is indeed stable, then an official announcement should be made of its existence.

[heehaw]

Thank you, Professional Beer Drinker, for posting HO3. It is amazing to me that I'd never heard of this until your post. It does seem to me that this is big news. NASA has been looking for somewhere to send people, and it seems to me that HO3 is a natural! Am I missing something? Here's Wikipedia on it: https://en.wikipedia.org/wiki/(469219)_2016_HO3

[heehaw]

Compare HO3 with our other Moon's path - our other Moon goes around the Sun too, you know!
https://en.wikipedia.org/wiki/Orbit_of_ ... ctory1.svg

[Case]

Wish to know whether the object is visible in the evening sky for observation from northern hemisphere.

First, this post is unrelated to today's APOD, thus should be elsewhere. Bystander informed us all about this news more than a month ago in the Science News forums. [Thanks for moving this, moderator ]
Second, it can be seen from the northern hemisphere, as it was discovered using the Pan-STARRS telescopes on Hawaii (20.7°N). You may need a 1.8 m (5.9 feet) telescope to see (photograph) the small, faint object. Currently it is at RA/DE 11h42m/-31°50', in Hydra, best seen very southern hemisphere. Next April will be good opportunity for the north, though.

[bystander]

Earth's New Traveling Buddy Is an Asteroid, Not Space Junk
University of Arizona | Large Binocular Telescope | 2017 Oct 17

Astronomers led by Vishnu Reddy of the UA's Lunar and Planetary Laboratory confirm the true nature of one of Earth's companions on its journey around the sun.

[img3="Just a space rock, not a tumbling rocket booster: Earth's traveling buddy 2016 HO3 is an asteroid that appears to orbit around Earth due to the mechanics of its peculiar orbit around the sun. (Credit: NASA JPL)"]https://cdn.uanews.arizona.edu/s3fs-pub ... 160615.jpg[/img3][hr][/hr]

Is it a bird? Is it a plane? Or maybe, as some have speculated, a burned-out rocket booster, trapped in a near-Earth orbit around the sun and only occasionally getting close enough to be studied with even the largest telescopes?

Not at all, as it turns out. Based on previous observations, most astronomers had strongly suspected that object (469219) 2016 HO3 was an ordinary asteroid and not space junk. But it took a team of astronomers led by Vishnu Reddy, assistant professor at the University of Arizona's Lunar and Planetary Laboratory, working with one of the world's largest telescopes, the Large Binocular Telescope, or LBT, on Mount Graham in southeastern Arizona, to learn the true nature of this near-Earth object.

2016 HO3 is a small near-Earth object, or NEO, measuring no more than 100 meters (330 feet) across that, while orbiting the sun, also appears to circle around the Earth as a "quasi-satellite." Only five quasi-satellites have been discovered so far, but 2016 HO3 is the most stable of them. The provenance of this object is unknown. On timescales of a few centuries, 2016 HO3 remains within 38-100 lunar distances from us. ...

Ground-based Characterization of Earth Quasi Satellite (469219) 2016 HO3 - Vishnu Reddy et al

Asteroid (469219) 2016 HO3, the smallest and closest Earth quasi-satellite - C. de la Fuente Marcos, R. de la Fuente Marcos

• Monthly Notices of the RAS 462(4):3441 (11 Nov 2016) DOI: 10.1093/mnras/stw1972
  arXiv.org > astro-ph > arXiv:1608.01518 > 04 Aug 2016 (v1), 16 Aug 2016 (v2)