Wednesday, November 9, 2011

2005 YU55 - Close Approach

On November 08, 2011 at 23:28 Universal Time (UT), the Near-Earth asteroid 2005 YU55 passed within 0.85 lunar distances (or 319,000 km or 0.00217 AU) from Earth's surface.

Asteroid 2005 YU55 was discovered by Robert McMillan during the Spacewatch survey on December 28, 2005. The 2011 approach is the closest that we know about in advance by an asteroid with an absolute magnitude this bright since 2010 XC15 (H = 21.4) approached within 0.5 lunar  distances in 1976 (although astronomers did not know about this flyby at the time), and until 2028, when 2001 WN5 (H = 18.2) will approach within 0.65 lunar distances.

The object has been previously observed on April 2010 by Mike Nolan, Ellen Howell and colleagues with the Arecibo radar on April 19-21, 2010 and shown to be a very dark, nearly spherical object 400 meters in diameter with a relatively long rotation period, 18 to 20 hours. 


Trajectory of Asteroid 2005 YU55 - November 8-9, 2011. Click on the thumbnail to see a bigger version:


(Credit: NASA-JPL)


We have been able to follow-up this object on November 09.25 remotely from the GRAS Observatory (near Mayhill, NM) through a 0.25-m, f/3.4 reflector + CCD. At the moment of our observing session the asteroid was moving at about 260.07 "/min and it was of magnitude ~11. The image below is a single 60-second exposure (click on it for a bigger version).




While this is an animation showing the object movement in the sky. Each image was a 2-second exposure. Click on the thumbnail to see a bigger version:



Scientists working with the 70-meter Deep Space Network antenna at Goldstone, California, have generated a short movie clip of asteroid 2005 YU55 from data  collected on November 07, 2011. These are the highest-resolution radar images ever obtained for a near-Earth object:



Due to its size and proximity to Earth, the Minor Planet Center has designated 2005 YU55 as a "Potentially Hazardous Asteroid". Although classified as a potentially hazardous object, 2005 YU55 poses no threat of an Earth collision over at least the next 100 years, the entire interval over which its motion can be computed reliably.

For more info about this close approach:

http://www.skyandtelescope.com/observing/home/133013563.html

http://echo.jpl.nasa.gov/asteroids/2005YU55/2005YU55_planning.html

http://neo.jpl.nasa.gov/news/news171.html


by Ernesto Guido, Giovanni Sostero and Nick Howes

1 comment:

Jorge Abeel said...

En el video más pequeño se ve al asteroide 2005Yu55 cuando se aproxima al objeto más luminoso en el ángulo superior izquierdo, se produce un destello de luz, que se adelanta al asteroide, no es que se sume con astro "inmóvil", quizás sea un defecto de la filmación, lo observé detenidamente, y allí está qué es no sé, espero no tener que ir al oculista, agradezco si alguien observa el mismo detalle del que hablo, reitero el flash de luz se adelanta a ambos objetos. Saludos. jorge