A Large and Long Program using simultaneous ultraviolet and near-infrared data from Gemini North and the Canada- France-Hawai ‘ i Telescope lead to the discovery of a peculiar population of blue-colored , tenuously bound binaries residing among the otherwise unanimously red “ cold classical ” Kuiper Belt objects . These widely separated binary objects could have survived perturbing forces during the early phases of Neptune ’ s migration , helping us to better understand the planet ’ s accretion history in the outer Solar System .
July 2017
Wes Fraser
Blue Binaries Suggest a Smooth Migration for Young Neptune
A Large and Long Program using simultaneous ultraviolet and near-infrared data from Gemini North and the Canada- France-Hawai ‘ i Telescope lead to the discovery of a peculiar population of blue-colored , tenuously bound binaries residing among the otherwise unanimously red “ cold classical ” Kuiper Belt objects . These widely separated binary objects could have survived perturbing forces during the early phases of Neptune ’ s migration , helping us to better understand the planet ’ s accretion history in the outer Solar System .
A Brief History of the Kuiper Belt
The Kuiper Belt is complicated , and weird . Consider its shape ( see Figure 1 ). First a disclaimer : the community uses the term belt pretty loosely . Imagine instead a broad torus hundreds of astronomical units ( AU ) thick and tens of AU tall , with a 30 AU radius hole cut out of the middle . That ’ s the true shape of the Kuiper Belt .
July 2017
Figure 1 .
Rendering of the outer Solar System . Small points correspond to the > 1,700 known and tracked objects . Colors correspond to different dynamical classes — the cold classicals are in red , the resonant plutino and twotino objects are in purple and yellow , the transitory centaurs are in white , and the non-resonant excited objects are in light blue . A handful of the orbits of this class are shown by the dotted blue lines . The gas-giant planets are the larger circles , and the largest ten dwarf planets are identified with white circles . Distances at 30 , 50 , and 100 AU are shown by the dashed white circles .
Beyond its poorly named shape , what really catches a scientist ’ s eye is the Belt ’ s layered dynamical structure . The first Kuiper Belt Object ( KBO ) discovered , 1992 QB1 , belongs to the so-called cold classical population , named for what may have been expected to reside beyond Neptune : a population of planetesimals on circular , low inclination orbits , in a ring ( or belt ).
Unlike the asteroid belt , whose empty Kirkwood gaps can clearly be attributed to the clearing effects of mean-motion
January 2018 / 2017 Year in Review GeminiFocus
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