Dawn mission scientists have been awarded time on the Hubble Space Telescope (HST). In the first accepted proposal, Jian-Yang Li, working with Co-Investigator Lucy McFadden, will observe the UV-absorption band on Ceres. In the second proposal, Mission PI, Chris Russell, will observe 2 Pallas (a once-in-20-years opportunity due to the asteroid's highly inclined orbit). Chris will be assisted by graduate student Britney Schmidt and the same observing team from past successful Ceres observations. What does this mean for Dawn? The bottom line: the first proposal gives us good science and helps Dawn scientists and engineers plan for arrival at Ceres; the second proposal gives us good comparison data since 2 Pallas is a Vesta-sized body at a Ceres distance from the sun.
Last summer's vote by members of the International Astronomical Union elevated Ceres from being merely the largest member of the asteroid belt to a prime candidate for "dwarf planet" status. And from what astronomers have learned about it recently, Ceres is making a good case for that promotion.
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The International Astronomical Union (IAU) determined that Ceres is a dwarf planet.
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The evidence is global. Evidence for the global planetary process, called differentiation, is revealed in a letter by Peter Thomas (Cornell University) to the journal Nature. Collaborators on the paper were Joel Parker, Elliot Young (Southwest Research Institute), Dawn Principal Investigator, Chris Russell with Lucy McFadden (University of Maryland) and Mark Sykes (Planetary Science Institute). The publication is titled, "Differentiation of the asteroid Ceres as revealed by its shape."
The observations by NASA’s Hubble Space Telescope show that Ceres shares characteristics of the rocky, terrestrial planets like Earth. According to Dr. Lucy McFadden, “Ceres is an embryonic planet. Gravitational perturbations from Jupiter billions of years ago prevented Ceres from accreting more material to become a full-fledged planet.”
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