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THE SEPARATION BETWEEN ASTEROIDS AND COMETS HAS BECOME LESS CLEAR WITH THE DISCOVERY OF A SMALL GROUP OF ASTEROIDS THAT DISPLAY COMET-LIKE DUST ACTIVITY. SOME OF THESE 'ACTIVE ASTEROIDS' ACTIVATE CLOSE TO THE SUN RENDERING NEAR-EARTH ASTEROIDS (NEAS) A NATURAL LABORATORY FORTHE STUDY OF THEIR ACTIVITY. TWO DISTINCT NEA SUB-POPULATIONS ARE ESPECIALLY SUSPECTED OF BEING POTENTIALLY ACTIVE FOR DIFFERENT REASONS: DORMANT COMETS AND NEAR-SUN ASTEROIDS.DORMANT COMETS ARE COMETARY NUCLEI THAT HAVE DEPLETED THEIRNEAR-SURFACE ICE RESERVOIRS AND DO NOT SHOW ACTIVITY IN THE FORM OF A COMA OR A TAIL. NEAR-SUN ASTEROIDS ARE NEAS WITH EXTREMELY LOW PERIHELION DISTANCES. WHILE ACTIVITY IN DORMANT COMETS IS LIKELY TO OCCUR AS A RESULT OF THE SUBLIMATION OF REMNANT SUB-SURFACE VOLATILES NEAR-SUN ASTEROIDS MIGHT ALSO DISPLAY ACTIVITY DUE TO THERMAL FRACTURE. ACTIVITY HAS BEEN OBSERVED IN CONSTITUENTS OF BOTH NEA SUB-POPULATIONS SUGGESTING THAT MORE OF THEIR MEMBERS MIGHT SHOWACTIVITY. THE STUDY AND CHARACTERIZATION OF BOTH ENSEMBLES PROVIDES UNIQUE INSIGHTS INTO THE MECHANISMS THAT DRIVE THEIR ACTIVITY AND PROVIDE IMPORTANT CONSTRAINTS ON ASTEROID PHYSICAL PROPERTIES ASWELL AS SOLAR SYSTEM FORMATION AND EVOLUTION MODELS.WE PROPOSE A COMPREHENSIVE STUDY THAT AIMS TO CHARACTERIZE AND MONITOR DORMANT COMETS AND NEAR-SUN ASTEROIDS. USING GROUND-BASED OBSERVATIONS WE WILL PUT CONSTRAINTS ON THEIR COMPOSITIONS AND PHYSICAL PROPERTIES AND SEARCH FOR ACTIVITY IN THEM. BY SUPPLEMENTINGOUR DATA WITH PAN-STARRS PHOTOMETRY WE WILL IMPROVE OUR RESULTS. THE FEASIBILITY OF OUR APPROACH HAS BEEN PROVEN IN A PILOT STUDY IN 2015.WE IDENTIFY DORMANT COMETS BASED ON THEIR ORBITS AND COLORS AND MONITOR THEM OVER THE COURSE OF THIS PROJECT IN SEARCH FOR ACTIVITY. OUR OBSERVATIONS WILL RESULT IN A BETTER CHARACTERIZATION OF THE FRACTION OF DORMANT COMETS IN THE NEA POPULATION AND THEIR VOLATILE CONTENT. FURTHERMORE OUR RESULTS WILL TEST COMET FORMATION MODELS. NEAR-SUN ASTEROIDS WILL BE TAXONOMICALLY CHARACTERIZED ANDMONITORED IN SEARCH FOR ACTIVITY. OUR OBSERVATIONS WILL PROVIDE CONSTRAINTS ON THE MATERIAL PROPERTIES OF DIFFERENT ASTEROID TAXONOMIC TYPES. FOR ALL OF OUR TARGETS ACCURATE ABSOLUTE MAGNITUDES LIGHTCURVE AMPLITUDES CONSTRAINTS ON THEIR TAXONOMY AND ASTROMETRY WILL BE REPORTED ALL OF WHICH HAVE SIGNIFICANT LEGACY VALUE.OUR GOALS CAN ONLY BE MET WITH A COMPREHENSIVE AND SYSTEMATIC OBSERVATIONAL PROGRAM AS IS PRESENTED HERE. THIS PROGRAM IS IN ACCORDANCE WITH THE ROSES-2016 SSO/NEOO SUBELEMENT SINCE WE WILL CHARACTERIZE A REPRESENTATIVE SAMPLE OF NEOS.

$27,326FY2017National Aeronautics and Space AdministrationNASA

Northern Arizona University, Flagstaff AZ

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