1866 in Science - Astronomical Objects Discovered in 1866, 90 Antiope, 87 Sylvia, 88 Thisbe, 89 Julia, 91 Aegina, 86 Semele (Paperback)

Chapters: Astronomical Objects Discovered in 1866, 90 Antiope, 87 Sylvia, 88 Thisbe, 89 Julia, 91 Aegina, 86 Semele, 1866 in Paleontology, 1866 in Archaeology. Source: Wikipedia. Pages: 30. Not illustrated. Free updates online. Purchase includes a free trial membership in the publisher's book club where you can select from more than a million books without charge. Excerpt: 90 Antiope - body{behavior: url("/w/skins-1.5/vector/csshover.htc")} 90 Antiope The most remarkable feature of Antiope is that it consists of two components of almost equal size (the difference in mass is less than 2.5%), making it a truly "double" asteroid. Its binary nature was discovered on 10 August 2000 by a group of astronomers using adaptive optics at the Keck Telescope on Mauna Kea. The "secondary" is designated S/2000 (90) 1. Each component is about 86 1 km across, with their centers separated by only about 170 kilometers. This means that the gap separating the two halves is a mere 60 km, or so. The two bodies orbit around the common center of mass which lies in the space between them. The orbital period is approximately 16.50 hours, the eccentricity below 0.03 (best estimate 0.01 0.02). Every several years, a period of mutual occultations occurs when the asteroid is viewed from Earth. Using Kepler's third law, the mass and density of the components can be derived from the orbital period and component sizes. The axis of the mutual orbit of the two components points towards ecliptic coordinates (, ) = (200, 38 ) with 2 degrees uncertainty. This is tilted about 63 to the circumsolar orbit of the system. The complementary observations using adaptive optic observations on 8-10m class telescopes and mutual events photometric lightcurve over several months have served as input quantities for a derivation of a whole set of other physical parameters (shapes of the components, surface scattering, bulk density, and internal properties). The shape model i...More: http: //booksllc.net/?id=583101