Spitzer Space Telescope - General Observer Proposal #80084 Eclipsing binary asteroid 2000 DP107 Principal Investigator: Michael Mueller Institution: Observatoire de la Cote d'Azur Technical Contact: Michael Mueller, Observatoire de la Cote d'Azur Co-Investigators: Jean-Luc Margot, UCLA Giovanni Fazio, Harvard Smithsonian CfA Howard Smith, Harvard Smithsonian CfA Joe Hora, Harvard Smithsonian CfA Marco Delbo, OCA Nice David Trilling, NAU Flagstaff Cristina Thomas, NAU John Kistler, NAU Alan Harris, DLR Berlin Michael Mommert, DLR Berlin Joshua Emery, University of Tennessee Shantanu Naidu, UCLA Science Category: near-Earth objects Observing Modes: IRAC Post-Cryo Mapping Hours Approved: 11.0 Abstract: We propose thermal observations of the eclipsing binary near-Earth asteroid 2000 DP107 before, during, and after two total secondary eclipses, where the secondary component is completely eclipsed by the primary. Through previous Spitzer observations, we have demonstrated (Mueller et al., 2010) that such observations enable a uniquely direct determination of the thermal inertia. Thermal-inertia measurements are crucial for constraining the surface properties by differentiating between regolith-covered, mature surfaces and younger bare-rock surfaces. Additionally, thermal inertia governs the important (for all D<10 km objects) Yarkovsky effect, a non-gravitational orbital drift due to thermal photons. Thanks to its low-deltaV orbit and our excellent knowledge about its physical properties (to which the proposed observations will add), 2000 DP107 is a desirable, low-risk target for spacecraft exploration.