University of Victoria, British Columbia | 05 Oct 2010
Neptune Acquitted on One Count of HarassmentNew research by a University of Victoria PhD student is challenging popular theory about how part of our solar system formed. At today’s meeting of the prestigious Division of Planetary Sciences in Pasadena, California, Alex Parker is presenting evidence that, contrary to popular belief, the planet Neptune can’t have knocked a collection of planetoids known as the Cold Classical Kuiper Belt to its current location at the edge of the solar system.
Parker and his thesis supervisor Dr. J.J. Kavelaars (Herzberg Institute of Astrophysics) studied binaries—systems of two objects that, like the Earth and the moon, travel around the sun while orbiting around each other. Binaries are very common in the Kuiper Belt. Using computer simulations, the researchers determined that binary systems in part of the Belt would have been destroyed by any interaction with the giant planet. “They would not be there today if the members of this part of the Kuiper Belt were ever hassled by Neptune in the past,” says Parker. “It suggests that this region formed near its present location and remained undisturbed over the age of the solar system.”
The Kuiper Belt is of special interest to astrophysicists because it is a fossil remnant of the primordial debris that formed the planets, says Parker. “Understanding the structure and history of the Kuiper Belt helps us better understand how the planets in our solar system formed, and how planets around other stars may be forming today.”
The research will be published in an upcoming edition of Astrophysical Journal Letters.
Universe Today | 05 Oct 2010
Destruction of Binary Minor Planets During Neptune Scattering - AH Parker, JJ KavelaarsA very popular explanation for the dynamical evolution of our solar system is being challenged by a new model that takes the blame away from Neptune for knocking a collection of planetoids known as the Cold Classical Kuiper Belt out to their current, distant home. PhD student Alex Parker from the University of Victoria in British Columbia, Canada presented evidence showing that the large population of binary objects in the Kuiper Belt gives witness to a different series of events than the Nice Model – which says Neptune’s migrations were responsible for a sending KBO’s into chaotic orbits. “Kuiper binaries paint a different picture,” Parker said during a press briefing at the American Astronomical Society’s Division of Planetary Sciences meeting this week. “I should title my talk as ‘Neptune not guilty of harassment’ or perhaps more accurately, “Planet Neptune acquitted of one count of harassment.’”
The Nice Model holds that the objects in the scattered Kuiper Belt were placed in their current positions by interactions with Neptune’s migrating resonances. Originally, the Model says, the Kuiper belt was much denser and closer to the Sun, with an outer edge at approximately 30 AU. Its inner edge would have been just beyond the orbits of Uranus and Neptune, which were in turn far closer to the Sun when they formed. As Neptune migrated outward, it approached the objects in the proto-Kuiper belt, capturing some of them into resonances and sending others into chaotic orbits.
But the survey of the Kuiper Belt being done by Parker and his thesis supervisor Dr. J. J Kavelaars (Herzberg Institute of Astrophysics), which has been running for a decade, tells a different story. “Thirty per cent of Kuiper Belt Objects are binaries, some in very wide orbits around each other in a slow waltz, weakly bound to their partners,” Parker said. “These binaries should have been destroyed if the Kuiper Belt Objects were thrown out of solar system.”
Since binaries are extremely common in the Kuiper Belt, they are useful tools for astronomers, said Parker. “Pluto and Charon are the most famous of these binaries and since their orbits can be affected by their environment, we can use them to test what the interplanetary environment is like and what it was like in the past.”
- arXiv.org > astro-ph > arXiv:1009.3495 > 17 Sep 2010
