1998 QE2 Asteroid Flyby An Opportunity For Pros And Amateurs Alike

Many separate telescopic images were combined to create this animation of asteroid 1998 QE2 moving through a star field this past week. Credit: Ernesto Guido and Nick Howes

An asteroid it would take an hour to walk across will speed past Earth on May 31 and provide radio astronomers a perfect opportunity to nab closeup views of its surface. 1998 QE2, discovered in 1998 by the Massachusetts Institute of Technology Lincoln Near Earth Asteroid Research (LINEAR) program,  will miss our planet by a healthy 3.6 million miles (5.8 million km) or 15 times the distance of the moon. Closest approach occurs at 3:59 p.m. Central time.

The asteroid’s large size combined with its relatively close approach makes it a great target for both the 230-foot (70-m) Goldstone radio dish and 1,000-foot (305-m) Arecibo dish in Puerto Rico. Lance Benner, the principal investigator for the Goldstone radar observations from NASA’s Jet Propulsion Laboratory in Pasadena, Calif., will have all hands on deck for the flyby. By sending bursts of radio waves at 1998 QE2 and measuring the retured radar echoes, Benner expects the dishes to resolve surface features as small as 12 feet (3.75m) across on the 1.7-mile-long asteroid (2.7 km).

The orbit of asteroid 1998 QE2. Its May 31 flyby will be the closest it comes to Earth for at least the next 200 years. Its closest point to the sun is similar to Earth’s; when farthest it’s 353 million miles from the sun in the asteroid belt between Mars and Jupiter. Credit: NASA/JPL-Caltech

Through an ordinary optical telescope, even a large one, 1998 QE2 will appear as a point of light. Radar observations reveal far more including shape, size, rotation and a wide variety of surface features. Goldstone observations are scheduled from May 30 – June 9; those at Arecibo for several days around June 5.

Already optical telescopes in the southern hemisphere have this monster rock in their crosshairs. By measuring repeating highs and lows in the asteroid’s brightness as it spins on its axis, astronomers can determine its rotation rate. 1998 QE2’s composition is gleaned by how it reflects sunlight. Reflected sunbeams streaming back to Earth carry the imprint of particular minerals that absorb and reflect portions of the sun’s light in unique ways that nail down their identities.

“It is tremendously exciting to see detailed images of this asteroid for the first time,” said Benner. “With radar we can transform an object from a point of light into a small world with its own unique set of characteristics. In a real sense, radar imaging of near-Earth asteroids is a fundamental form of exploring a whole class of solar system objects.”

1998 QE2 looks like a point of light in this time exposure taken remotely with a telescope in Australia by the team of Ernesto Guido and Nick Howes. The asteroid is currently very faint and only visible in the southern hemisphere. Click for more on the asteroid in their blog.

I’m excited about the asteroid because it will be bright enough to be visible in small telescopes across both northern and southern hemispheres for several nights around the time of closest approach. Between May 30 and June 5 it will shine at 10.5-11.0 magnitude while chugging through the constellations Libra and Ophiuchus, both conveniently placed at nightfall. Its steady movement across the sky – 2/3 of a full moon diameter an hour – will be obvious through the telescope. Come the end of the month, I’ll create a map to help you find it.

Read more about 1998 QE2 HERE. Amateur astronomers needing orbital elements and ephemerides can check out the Goldstone planner.

12 Responses

  1. Tim Hutton

    Hello Bob.
    I just noticed they have changed the estimated size to 1.8 km. Is this another mistake I am seeing? After the X flare blunder, I’m just not sure anymore.

        1. astrobob

          I’m thinking theirs is either an older figure or they forgot to convert miles to kilometers.

  2. Daltry Le Boeuf

    hmm okay, thanks. do you know of any websites that are going to be streaming the passing of this asteroid? and thanks again for the quick response!

  3. Judy

    I’m scared…how do they KNOW its not going to hit us? What about gravity pull? The closest it will be is about 4:00….Central time………..looking forward to seeing 5: 00 !!!

    1. astrobob

      No sweat about gravity pull. This thing’s much too far away and moving at many thousands of miles an hour along it own path for Earth to alter its orbit. In order for it to actually hit the Earth, it would have to be on a trajectory straight at the planet and it’s far, far, far from that. Just basic physics – no worries.

        1. astrobob

          If it did one day hit Mars – and no one is predicting it – it would be done for. Once something strikes another planet, it can’t come around again.

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