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2009 Annual Science Report

University of Hawaii, Manoa Reporting  |  JUL 2008 – AUG 2009

Main Belt Comet P/2008 R1 Garradd Characterization

Project Summary

We identified P/2008 R1 as a main-belt comet (previously mis-classified as an ordinary Jupiter-family comet) and mounted an observational program to assess its physical properties, and a dynamical campaign to understand its orbit.

4 Institutions
3 Teams
1 Publication
1 Field Site
Field Sites

Project Progress

Main-belt comets are objects with the dynamical characteristics of an asteroid and the physical characteristics of a comet (see Figure 1). P/2008 R1 is a newly-discovered comet and is identified as the 4th MBC. We obtained limits to its size (500 m) and mass loss rate (< 1 kg/s). Unlike the previously reported MBCs, P/2008R1 is dynamically unstable with a lifetime of ~ 20-30Myr (see Figure 2). P/2008R1, as a new type of MBC, must have been recently emplaced from a longer-lived source elsewhere, perhaps in the outer belt. The work is already published as

D. Jewitt, B. Yang and N. Haghighipour (2009). Main-Belt Comet P/2008 R1 (Garradd). Astronomical Journal, 137, 4313-4321.

Figure 1. ​R-band image of P/2008 R1, taken at the Keck telescope. A faint tail extends to the northeast from the nucleus of the comet. The projected Sun-comet radius vector is denoted by “-Sun”.

Figure 2. ​Semimajor axis versus eccentricity for numbered asteroids (small black dots) with the four known MBCs marked in color. The Mean motion resonances (MMR) with Jupiter are labeled by dashed lines. P/2008 R1 is located near the J8:3 MMR and is therefore dynamically unstable.

    Nader Haghighipour
    Unspecified Role

    David Jewitt
    Unspecified Role

    Bin Yang
    Unspecified Role

    Objective 1.1
    Formation and evolution of habitable planets.

    Objective 2.2
    Outer Solar System exploration

    Objective 3.1
    Sources of prebiotic materials and catalysts