Archive for April 17th, 2011

“Blinking” asteroid passes the Earth

This interesting near-Earth asteroid was discovered by the Spanish La Carpa survey on April 8th, receiving the designation 2011 GP59. Several hours after the discovery of the object, one of its discoverers, Jaime Nomen reported that the object noticeably varied in brightness with an amplitude of more than two magnitudes! This is very significant; most asteroids, due to their rotation, vary in brightness by tenths of a magnitude.

Lowell observatory / Brian Skiff

Many asteroid observers have observed this new guest, and we have received precise photometric curves (graphs of the change in brightness with time). One of the astronomers was Brian Skiff, working at Lowell Observatory. You can see the graph at left.

The period of rotation of asteroid 2011 GP59 is just 7.5 minutes, although this is far from the fastest rotating asteroid. The record belongs to asteroid 2010 TD54; it makes a full rotation on its axis in just 42 seconds!

Above, you can easily see how asteroid 2011 GP59 “blinks”. This animation was made by Nick James using his 28-cm telescope. At the time of the image, the asteroid was located 3,356,000 km from Earth – 1.4 times the average distance from the Earth to the Moon. Its closest distance to the Moon on this passage was 2.3 times less than that- just 236,000 km. The next time this asteroid passes by the Earth will be April 9, 2028.
April 2011
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