Surprise! Earth Passing Asteroid 1998 QE2 Has a Moon

by Nancy Atkinson on May 30, 2013

Want to stay on top of all the space news? Follow @universetoday on Twitter

Radar images from May 29, 2012 of Asteroid 1998 QE2, showing its binary companion. Credit: NASA.

Radar images from May 29, 2012 of Asteroid 1998 QE2, showing its binary companion. Credit: NASA.

Late yesterday, NASA turned the 230-foot (70-meter) Deep Space Network antenna at Goldstone, California towards Asteroid 1998 QE2 as it was heading towards its closest approach to Earth, and they got a big surprise: the asteroid is a binary system. 1998 QE2 itself is 1.7 miles (2.7 kilometers) in diameter, and the newly found orbiting moon is about 600 meters in diameter.

The radar images were taken were taken on May 29, 2013, when the asteroid was about 3.75 million miles (6 million kilometers) from Earth.

“Radar really helps to pin down the orbit of an asteroid as well as the size of it,” said Paul Chodas of NASA’s Near-Earth Object Program office, speaking during a JPL webcast about this asteroid on May 30. “We now know our size estimates were pretty good, but finding it was a binary was surprising.”

NASA said that about 16 percent of asteroids are binary or even triple systems.

Each of the images above are snippets of about 5 minutes of radar data. You can watch a movie of the data, below:

Other surprises were several radar-dark features, which may be cavities or impact craters, said Marina Brozovic, a scientist at JPL. The asteroid is also rotating more slowly than originally thought.

Near Earth Asteroid (NEA) 285263 (1998 QE2) will pass 5.86 million km from the Earth on Friday, May 31st at 20:59 Universal Time (UT) or 4:59PM EDT. This is the closest approach of 1998 QE2 for this century, and it poses no threat – and there’s not any threat in the future – as it is passing over 15 times as distant as the Earth’s Moon. But the rather large size of this space rock makes it an object of interest for astronomers.

Chodas added that they will continue to take radar data of this asteroid while they can to improve its orbital parameters, and that the presence of the moonlet means they can get an even more precise mass estimate of the asteroid.

Want to try and see this asteroid for yourself? Our very own David Dickinson has written a great “how-to” for this object, but you are going to need a fairly large backyard telescope, since it will be about 100 times fainter than what can be seen with the naked eye, even at closest approach.

The Slooh online telescope will have views of online tomorrow, which you can watch at their website. The webcast will start at 20:30 UTC (4:30 p.m. EDT) on Friday, May 31.

Also, starting at 20:00 UTC (4:00 p.m. EDT), astrophysicist Gianluca Masi will have a webcast from the Virtual Telescope Project in Italy.

Additionally, if you want to have a Bruce Willis-type view of this asteroid, check out NASA’s Eyes on the Solar System. They have a special feature on this asteroid, and you can “ride along with it for the next few days,” said Doug Ellison, Visualization Producer at JPL, speaking during the webcast.

This amazing tool creates realistic simulated views based on real data, and allows you to travel to any planet, moon or spacecraft across time and space, in 3D and in real time — or speed up to see the future.

Just go to the Eyes on the Solar System website, and when the window opens, click on “Tours and Features” in the upper right hand corner, then click on “1998 QE2″ in the dropdown box, and away you go. If you click on the “Live” button the left, you’ll see the current location; click on “Ride Along” and find yourself sitting on the asteroid heading towards Earth.

At the bottom control panel “dock” (click on the bottom box on the lower right side if the panel isn’t showing), you can speed up time and see how far from Earth this asteroid will get and where it will go in the future.

Ellison added that right now the imagery on Eyes on the Solar System doesn’t have the moonlet orbiting 1998 QE2, but they will be adding it soon to make the visualization as realistic as possible.

NASA’s @AsteroidWatch Twitter account shared the news about the moon:

Also, if you want more asteroids, on Friday May 31, the White House is hosting an asteroid-themed “We the Geeks” Google+ Hangout starting at 2 p.m. EDT.

The live video conference will feature Bill Nye the Science Guy, former astronaut Ed Lu, NASA Deputy Administrator Lori Garver, and Peter Diamandis, co-founder of asteroid mining company Planetary Resources. They will discuss identification, resource potential and threat of asteroids. Here’s the link the White House’s Google+ page.


Nancy Atkinson is Universe Today's Senior Editor. She also is the host of the NASA Lunar Science Institute podcast and works with Astronomy Cast. Nancy is also a NASA/JPL Solar System Ambassador.

Minor Planet Center May 30, 2013 at 7:24 PM

“Near Earth Asteroid (NEA) 285263 (1998 QE2) will pass 6.2 million kilometers from the Earth”

A little typo there, Nancy: 1998 QE2′s closest approach will be ~5.86 million km away.

—JL Galache
Minor Planet Center

NancyAtkinson May 30, 2013 at 8:29 PM

Thank you!

Minor Planet Center May 30, 2013 at 8:54 PM

It’s what we’re here for, Nancy, keeping tabs on the Solar System and the Interwebs ;-)

—JL Galache
Minor Planet Center

Ben Bernanke May 30, 2013 at 9:06 PM

Please change orbit and hit the federal reserve building. The only way to end QE is for an asteroid to hit Bens printing presses. Paul Krugman will be happy, while it may not be the alien invasion he was looking for to stimulate GDP growth, this should do nicely as a substitute. We should get at least 100 points on the DOW and 50 on the S&P if this even occurs.

DurkaDurka May 30, 2013 at 10:06 PM

So, that’s not good. So near Earth asteroid is now Nearer Earth Asteroid.

Aqua4U May 30, 2013 at 11:40 PM

Any spectroscopy available for QE2 and partner? Simple chondrite rock(s)? The moonlet appears to have high reflectivity… an icy body?

Minor Planet Center May 30, 2013 at 11:57 PM

No spectroscopy that I’m aware of, certainly not of the moon. We do know it’s a VERY dark asteroid—tit only reflects 6% of the visible light hitting it.

The moon appears bright in the radar images because it’s probably rotating very slowly.

—JL Galache
Minor Planet Center

steph mcd May 31, 2013 at 4:38 PM

A litle typo there, JL. “…tit only reflects 6% of the visible light hitting it…” Or have you inadvertently posted some of your own private bedroom research? ;-)

Grimbold May 30, 2013 at 11:53 PM

Why is the little moon so much brighter than the asteroid?

Minor Planet Center May 31, 2013 at 12:06 AM

A much longer (and better) explanation than mine by Emily Lakdawalla:


—JL Galache
Minor Planet Center

Grimbold May 31, 2013 at 2:32 AM

Thanks for that link. These dopplergrams always confuse me because the images sometimes look like the object and sometimes they don’t.

Bill May 31, 2013 at 12:42 AM

Moons usually orbit things, they don’t go in straight lines. Are you sure it’s not shooting at us?

Richard Colby-leveymg May 31, 2013 at 1:26 AM

Surprise, 1998 QE2 is a “planet” according to the In’t Astrological Union (IAU) definition.
Scroll down to the bottom of the post here:

Apparently it has sufficient mass to retain its own satellite, which
is surprising. Both of them are soon to be visiting our part of the
solar system.

The fact that it has a moon shows that 1998 that it has “cleared its
neighborhood” of other objects, and is is a full-fledged planet,
according to another IAU definition:

“Clearing the neighbourhood of its orbit” is a
criterion for a celestial body to be considered a planet in the Solar
System. This was one of the three criteria adopted by the International
Astronomical Union (IAU) in its 2006 definition of planet.

In the end stages of planet formation, a planet will have “cleared
the neighbourhood” of its own orbital zone, meaning it has become
gravitationally dominant, and there are no other bodies of comparable
size other than its own satellites or those otherwise under its
gravitational influence. A large body which meets the other criteria for
a planet but has not cleared its neighbourhood is classified as a dwarf
planet. This includes Pluto, which shares its orbital neighbourhood
with Kuiper belt objects such as the plutinos. The IAU’s definition does
not attach specific numbers or equations to this term, but all the
planets have cleared their neighbourhoods to a much greater extent than
any dwarf planet, or any candidate for dwarf planet.

The phrase may be derived from a paper presented to the general
assembly of the IAU in 2000 by Alan Stern and Harold F. Levison. The
authors used several similar phrases as they developed a theoretical
basis for determining if an object orbiting a star is likely to “clear
its neighboring region” of planetesimals, based on the object’s mass and
its orbital period.

Clearly distinguishing “planets” from “dwarf planets” and other
minor planets had become necessary because the IAU had adopted different
rules for naming newly discovered major and minor planets, without
establishing a basis for telling them apart. The naming process for Eris
stalled after the announcement of its discovery in 2005, pending
clarification of this first step.

This could change the way we view planetary systems, or that moon could just be an interstellar craft in a parking orbit. ;-)

Minor Planet Center June 3, 2013 at 2:08 PM


There are many Near Earth Asteroids in orbits similar to 1998 QE2, so it hasn’t fulfilled that particular requirement of clearing its orbit. Being a binary asteroid has noting to do with clearing its neighbourhood.

—JL Galache
Minor Planet Center

Blahable May 31, 2013 at 3:29 AM


Planemo May 31, 2013 at 7:47 AM

No, no , no …no , come on you guys. You all don’t know who that lil’shinny dude is napping beside that asteroid? No?
Ok, I’ll have to tell you then. He is actually none other then the most vulgar lil’alien dude in the solar system. The woman from Venus cannot get enough of the lil’alien dude. Why its the one and only “Anus from Uranus”. And you all call yourselves scientists?!


Glen May 31, 2013 at 1:55 PM
JonHanford May 31, 2013 at 3:00 PM

Yes, but Tom Van Flandern’s “Exploded Planet Hypothesis” would seem to be in doubt. In light of Tom’s NEAR Challenge (“If the NEAR rendezvous with Eros [in January, 1999] shows it to be an isolated, single body, or even a simple ‘binary asteroid’, but without a debris field orbiting it, I will publicly concede before the next Division of Planetary Sciences meeting that the hypothesis leading to that prediction has failed.”) I wonder if Dr Van Flandern made good on the wager? Tom Van Flandern passed away in 2009 and mysteriously his web site has no more about the challenge or the NEAR results(AFAIK no debris fields or moons were found at Eros by NEAR):

Glen June 2, 2013 at 3:35 AM

Hi Jon, thanks for the thoughtful comments. I’m not here to defend what Dr. Van Flandern did, but your question seems to be addressed here:

JonHanford June 2, 2013 at 2:37 PM

Thanks for the link Glen.

1MadMax1 May 31, 2013 at 6:22 PM

1998 QE2′s moon should be named ‘Monty’….after Queen Elizabeth’s Corgi, that recently died. Just sayin.

Isisosiris June 1, 2013 at 2:39 PM

Not only do this classified asteroid seem to hold a near full sphere shape … but I’m reminded of an old star wars saying … “that’s no moon, that’s a base station !” and for the celestial/alien minded having considered advance technology controlling much of what we see as reality … once an object comes into the solar system’s field of illusion, that object will appear to be any corresponding thing the illusion field is program to cast … so the visiting object could very well be a domicile space craft of some kind …

Minor Planet Center June 3, 2013 at 2:33 PM

Then again…it might just be an asteroid. Just sayin’…

—JL Galache
Minor Planet Center

Comments on this entry are closed.

Previous post:

Next post: