Friday, May 17, 2013

Close Approach of Asteroid (285263) 1998 QE2

Asteroid (285263) 1998 QE2 was discovered on Aug. 19, 1998, by the Massachusetts Institute of Technology Lincoln Near Earth Asteroid  Research (LINEAR) program.

1998 QE2 has an estimated size of 1.3 km - 2.9 km (based on the object's absolute magnitude H=16.6). It was observed by the Spitzer Space Telescope by Trilling et al. (2010), who estimated that it has a diameter of 2.7 km and a dark optical albedo of  0.06. This asteroid will have a close  approach with Earth at about 15.2 LD (Lunar Distances = ~384,000 kilometers) or 0.0392 AU (1 AU = ~150 million kilometers) at  2059 UT on 2013 May 31 and it will reach the peak magnitude ~10.8 on May 31 around 2300 UT.

(285263) 1998 QE2 will be a great Goldstone radar target May 30 through June 9. This is going to be one of the best radar targets of the year. Radar images from the Goldstone antenna could achieve resolutions as fine as 3.75 meters.

We performed some follow-up measurements of this object, from the Q62 iTelescope network (Siding Spring) on  2013, May 17.36, through a 0.50-m f/6.8 astrograph + CCD + f/4.5 focal reducer. Below you can see our image, stack of 15x10-second exposure, taken with the asteroid at magnitude ~14.5 and moving at ~3.13 "/min. At the moment of the close approach 1998 QE2 will move at ~23 "/min. Click on the image below to see a bigger version. North is up, East is to the left.


Below you can see a short animation showing the movement of 1998 QE2 (15x10-second exposures). Click here or on the thumbnail for a bigger version:

 photo 2852631998QE2_T30_Q62_17_May_2013_zpsfa800503.gif

  
UPDATE - May 30, 2013

Radar images of asteroid 1998 QE2 obtained on the evening of May 29, 2013, by NASA scientists (led by scientist Marina Brozovic) using the 70-meter Deep Space Network antenna at Goldstone, Calif., show that it is a binary system.

Credit: NASA/JPL-Caltech/GSSR

According to the JPL press release: "Radar images suggest that the main body, or primary, is approximately 2.7 kilometers in diameter and has a rotation period of less than four hours. Also revealed in the radar imagery of 1998 QE2 are several dark surface features that suggest large concavities. The preliminary estimate for the size of the asteroid's satellite, or moon, is approximately 2,000 feet (600 meters) wide. The radar collage covers a little bit more than two hours. In the near-Earth population, about 16 percent of asteroids that are about 200 meters or larger are binary or triple systems."




UPDATE - May 31, 2013

We performed some follow-up measurements of this object on 2013, May 31.3 (few hours before its close approach), remotely from the iTelescope Observatory (H06 Mpc code), through a 0.25-m f/3.4 reflector + CCD. Below you can see our image, 1 single exposure of 180 seconds, taken with the asteroid at magnitude ~11.0 and moving at ~ 21.72 "/min. The asteroid is trailed in the image due to its fast speed. Click on the image below to see a bigger version. North is up, East is to the left.


Below you can see a short animation showing the movement of 1998 QE2 (20 consecutive 10-second exposures). North is up, East is to the left. Click here or on the thumbnail for a bigger version:

Animation of (285263) 1998 QE2 on May 31, 2013 by E. Guido & N. Howes photo 1998QE2_May_31_H06_zps64069369.gif

by Ernesto Guido & Nick Howes

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