The 2012 laureates in Astrophysics
The Norwegian Academy of Science and Letters has decided to award the Kavli Prize in Astrophysics for 2012 to
University of California, Los Angeles, CA USA
Massachusetts Institute of Technology, USA
California Institute of Technology, Pasadena, CA USA
“for discovering and characterizing the Kuiper Belt and its largest members, work that led to a major advance in the understanding of the history of our planetary system.”
Beyond the orbit of Neptune lies the Kuiper Belt (also referred to as the Edgeworth- Kuiper Belt), a disk of more than 70,000 small bodies larger than 100 km in diameter made of rock and ices, and orbiting the Sun. This year’s Kavli Prize in Astrophysics honours two scientists who discovered the Kuiper Belt and a scientist who discovered many of its largest members.
Jewitt, Luu, and Brown’s discoveries were each the result of cleverly designed observational campaigns aimed specifically at detecting new classes of distant objects in the Solar System. Their research required creative strategies, a great deal of persistence, and an open-minded approach to expect the unexpected.
David Jewitt and Jane Luu discovered the first Kuiper Belt Object, known as 1992 QB1, in 1992. Their Slow Moving Objects survey, which lasted almost a decade, used progressively larger CCD cameras to detect faint objects moving slowly relative to background stars. Their discovery of the Kuiper Belt and subsequent investigation of the composition of Kuiper Belt Objects is bringing new insight into the early history and current state of the Solar System.
Kuiper Belt Objects appear to be primitive bodies that are remnants of the early stages of solar system formation, when the giant planets (Jupiter, Saturn, Uranus, and Neptune) were accreting surrounding gas, dust, and ices. Although the giant planets eventually swept up most of the nearby primitive bodies, it is thought that the Kuiper Belt, which lies well outside the giant planets’ orbits, contains fossils left over from the process of planet formation. Their composition and orbital characteristics thus offer a unique probe to the earliest phases of the Solar System.
Michael Brown designed and implemented the Caltech Wide-Area Survey, which observed an area of 20,000 square degrees in the plane of the Solar System. This survey was specifically optimized for detecting the most massive Kuiper Belt Objects. Brown’s discovery of Quaoar (2002), Makemake (2005), Eris (2005), and many other large Kuiper Belt Objects made it clear that Pluto is only one of many such objects. Because the largest Kuiper Belt Objects are also among the brightest, it is possible to use spectroscopy for quantitative characterization of the materials that make up their surfaces.
Equally important is Brown’s discovery of Sedna. Sedna has an exceptionally long and elongated orbit with an orbital period of more than 10,000 years. Its closest approach to the Sun (76 times the Earth–Sun distance) is more than twice the size of Neptune’s orbit. There has been an active debate about Sedna’s origin. Two interesting possibilities are that Sedna might have been tugged into its current orbit by a passing star, or may have been captured from a different solar system.