Great Expectations: The New Horizons Imaging and Composition Pre-Encounter Plans and Contemplations of 2014 MU69
Abstract
The New Horizons encounter with 2014 MU69 on 1 January 2019 will be the first small Kuiper belt object to be studied in detail from a spacecraft. The prospect that the cold classical population, which includes 2014 MU69, may represent a primordial, in situ population is exciting. Indeed, as we have learned just how complex and dynamic the early Solar System was, the cold classical population of the Kuiper belt has emerged as a singular candidate for a fundamentally unaltered original planetesimal population. MU69 in particular provides a unique opportunity to explore the disk processes and chemistry of the primordial solar nebula. As such, compositional measurements during the NH flyby are of paramount importance. So is high-resolution imaging of shape and structure, as the intermediate size of MU69 (much smaller than Pluto but much larger than a typical comet) may show signs of its accretion from much smaller bodies (layers, pebbles, lobes, etc., in the manner of 67P/C-G), or alternatively, derivation via the collisional fragmentation of a larger body if KBOs are "born big". MU69 may also be big enough to show signs of internal evolution driven by radiogenic heat from 26Al decay, if it accreted early enough and fast enough. The size of MU69 (20 - 40 km) places it in a class that has the potential to harbor unusual, and in some cases, possibly active, surface geological processes: several small satellites of similar size, including Helene and Epimetheus, display what appears to be fine-grained material covering large portions of their surfaces, and the surface of Phobos displays an unusual system of parallel grooves. Invariably, these intriguing surface features are only clearly defined at imaging resolutions of at least tens of meters per pixel. The best images of MU69 are planned to have resolutions of 20 - 40 m/pixel at a phase angle range of 40 - 70°. We also plan color imaging in 4 channels at 0.4 to 1 µ at 200 - 500 m/pixel, and 256 channel spectroscopy from 1.25 to 2.5 µ at 1 - 4 km/pixel. Ices such as H2O, NH3, CO2, and CH3OH would be stable and can be detected and mapped if they are exposed at the surface. It will be especially instructive to compare with Cassini VIMS spectra of Phoebe, thought to be a captured outer solar system planetesimal that formed in a related nebular environment to where MU69 formed.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2017
- Bibcode:
- 2017AGUFM.P13F..09M
- Keywords:
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- 6270 Pluto and satellites;
- PLANETARY SCIENCES: SOLAR SYSTEM OBJECTS;
- 6285 Trans-Neptunian objects;
- PLANETARY SCIENCES: SOLAR SYSTEM OBJECTS;
- 5405 Atmospheres;
- PLANETARY SCIENCES: SOLID SURFACE PLANETS;
- 5410 Composition;
- PLANETARY SCIENCES: SOLID SURFACE PLANETS