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Eyes on the Kuiper Belt

With the launch of the New Horizons mission to Pluto, Charon and beyond a scant month away, it’s fitting to acknowledge the 100th birthday of Gerard P. Kuiper, who predicted the existence of the band of debris and minor planets we now call the Kuiper Belt in 1950. It would take forty years for confirmation of the prediction, but the study of objects large and small beyond the orbit of Neptune now has high visibility, and is one of the reasons for the New Horizons mission.

Kuiper’s work was hardly limited to the now famous belt. He was also a pioneer in the study of Cepheid variables, those highly useful ‘standard candles’ that allow us to assess stellar distances (the period of a Cepheid variable being related to its intrinsic luminosity). Other objects of Kuiper’s interest included eclipsing binaries, and he played a key role in early work on Titan’s atmosphere. Add to this that his students included the likes of William Hartmann, Carl Sagan, and New Horizons Science Team Co-Investigator Dale Cruikshank (NASA Ames).

From a news release from Southwest Research Institute (San Antonio) about the man sometimes called ‘the father of planetary science”:

“Kuiper studied the planets at a time, 50 years ago, when they were scarcely of interest to other astronomers,” says Dr. Bill McKinnon, New Horizons co-investigator and professor of Planetary Sciences at Washington University in St. Louis, Mo. “But with new telescopes and instrumentation, he showed that there were great things to discover, which is as true today as then — witness the recent discovery of two new moons of Pluto. His planetary expertise later proved invaluable to NASA as well, especially during the early days of the race to our moon.”

Centauri Dreams‘ take: Kuiper’s birthday is justly celebrated, as is his career, but students of the Kuiper Belt also know that the first detailed discussion of a debris ring beyond Neptune was advanced by Kenneth Edgeworth in 1943, some years before Kuiper. Edgeworth made his case for an outer debris belt a second time in 1949, this time in a paper written for the Monthly Notices of the Royal Astronomical Society. John Davies tells the tale of this eccentric British soldier, engineer and amateur astronomer in his fine book Beyond Pluto (Cambridge University Press, 2001), and speculates on the reasons why Kuiper, who surely knew of Edgeworth’s prior work, chose to ignore him (the options are several, none of them surprising to anyone who has worked in academics).

As for New Horizons, launch is scheduled during the 35-day window that opens on January 11, with Pluto encounter in 2015. Although five striking workers from the International Association of Machinists and Aerospace Workers were involved in the final assembly of the vehicle’s third-stage, Boeing was able to replace the strikers with non-striking workers, each of whom has a minimum of eight years of experience with Boeing upper stage engines like this mission’s STAR 48 solid-propellant kick motor. The New Horizons team seems confident, but to these eyes the early November strike has injected an unwelcome dose of drama into the launch.

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  • ljk March 22, 2007, 9:41

    Astrophysics, abstract

    From: Alessandro Morbidelli [view email]

    Date: Wed, 21 Mar 2007 13:56:40 GMT (522kb)

    The Dynamical Structure of the Kuiper Belt and its Primordial Origin

    Authors: A. Morbidelli, H.F. Levison, R. Gomes

    Comments: to be published in `Transneptunian Objects’, Barucci et al. eds., University of Arizona Press

    This chapter discusses the dynamical properties of the Kuiper belt population. Then, it focuses on the characteristics of the Kuiper belt that cannot be explained by its evolution in the framework of the current solar system. We review models of primordial solar system evolution that have been proposed to reproduce the Kuiper belt features, outlining advantages and problems of each of them.


  • ljk April 28, 2008, 13:20

    A Subaru Archival Search for Faint TNOs

    Authors: Cesar I. Fuentes, Matthew J. Holman (Harvard, CfA)

    (Submitted on 21 Apr 2008)

    Abstract: We present the results of a survey for trans-neptunian objects (TNOs) based on Subaru archival images, originally collected by Sheppard et al. (2005) as part of a search for irregular satellites of Uranus. The survey region covers 2.8 deg^2, centered on Uranus and observed near opposition on two adjacent nights.

    Our survey reaches half its maximum detection efficiency at R=25.69$\pm$0.01. The objects detected correspond to 82 TNOs, five Centaurs, and five irregular satellites.

    We model the cumulative number of TNOs brighter than a given apparent magnitude with both a single and double power law. The best fit single power law, with one object per square degree at magnitude $R_0 =22.6_{-0.4}^{+0.3}$ and a slope of $\alpha = 0.51_{-0.6}^{+0.5}$, is inconsistent with the results of similar searches with shallower limiting magnitudes. The best fit double power law, with a bright-end slope $\alpha_1 = 0.7_{-0.1}^{+0.2}$, a faint-end slope $\alpha_2=0.3_{-0.2}^{+0.2}$, a differential number density at R=23, $\sigma_{23} = 2.0_{-0.5}^{+0.5}$ and a magnitude break in the slope at $R_{eq} = 24.3_{-0.1}^{+0.8}$, is more likely than the single power law by a Bayes factor of ~26.

    This is the first survey with sufficient depth and areal coverage to identify the magnitude at which the break occurs without relying on the results of other surveys. …

    Comments: Accepted for Publication in the Astronomical Journal, April 20th, 2008 [29 pages, 18 figures]

    Subjects: Astrophysics (astro-ph)

    Cite as: arXiv:0804.3392v1 [astro-ph]

    Submission history

    From: Cesar Fuentes [view email]

    [v1] Mon, 21 Apr 2008 20:00:22 GMT (125kb)