Astronomers Discover Moon Orbiting Asteroid
Press Release Text
(Images in various formats are available here.)
The above infrared image (1.6 microns) is a superposition of 5 detections of the new moon (taken --clockwise from top-- on the nights of Nov 1998, 6, 7, 9, 10, and 1 UT). The blue dashed line shows the orbit of the moon around the primary asteroid (45) Eugenia. The period of the orbit is 4.7 days. The moon travels in a clockwise direction (with North up and East to the left). The radius of the orbit is 1190 km. The main asteroid's diameter is close to 215 km (depicted here as a central white circle) and we estimate the moon's size is 13 km in diameter. The moon is 285 times fainter than the main asteroid and is very close to the main asteroid (just over 5 asteroid diameters away, or 0.77 arcseconds on the sky). Image processing (deconvolution) was used to increase the contrast between the moon and the main asteroid. The apparent variations in the moon's brightness and size are artificially produced due to changes in the atmospheric clarity from night to night.
Utilizing adaptive optics this image (resolution of approximately 185 km or 0.12 arcseconds on the sky) is 6 times sharper than could have been otherwise obtained from the ground. Images taken with the PUEO adaptive optics system of the Canada-France-Hawaii Telescope located on Mauna Kea, Hawaii.
Photo Credit: Laird Close (European Southern Observatory, Munich, Germany), Bill Merline (Southwest Research Institute, Boulder, CO, USA)
Dr. William J. Merline firstname.lastname@example.org Southwest Research Institute Boulder CO USA Dr. Laird Close email@example.com European Southern Observatory Munich, Germany Dr. Christophe Dumas firstname.lastname@example.org Jet Propulsion Laboratory Pasadena, CA USA Dr. Clark R. Chapman email@example.com Southwest Research Institute Boulder, CO USA Dr. Francois Roddier firstname.lastname@example.org Institute for Astronomy University of Hawaii Honolulu, HI USA Dr. Francois Menard email@example.com Canada-France-Hawaii Telescope Corp. Kamuela, HI USA Dr. David Slater firstname.lastname@example.org Southwest Research Institute San Antonio, TX USA Dr. Gilles Duvert email@example.com Laboratoire d'Astrophysique de Grenoble Grenoble, France Dr. Chris Shelton firstname.lastname@example.org W.M. Keck Observatory Kamuela, HI USA Dr. Tom Morgan email@example.com NASA Headquarters Washington, DC USA
Last updated 06-Oct-1999 by Will Colwell