President and Fellows of Harvard College

BENJAMIN WEISS FOCUSES ON THE FORMATION, EVOLUTION, AND HISTORY OF THE TERRESTRIAL PLANETS ANDSMALL BODIES, WITH PARTICULAR INTERESTS IN PALEOMAGNETISM AND GEOMAGNETISM, PLANETARY GEOPHYSICS, METEORITICS, AND PLANETARY PALEOCLIMATE AND HABITABILITY. HE STUDIES METEORITES AND SAMPLES FROM EXTRATERRESTRIAL BODIES TO UNDERSTAND THE HISTORY OF THESE PLANETARY GEOPHYSICAL AND GEOCHEMICAL PROCESSES. HE WILL DEVISE PALEOMAGNETIC STUDIES OF 10 – 12 SELECT SMALL BENNU PARTICLES, WILL ANALYZE AND INTERPRET THE MEASUREMENTS, AND INFER THE BROADER IMPLICATIONS OF THE FINDINGS. EDUARDO ANDRADE LIMA IS AN EXPERT IN SCANNING MAGNETIC MICROSCOPY AND INVERSE PROBLEMS FOR MAGNETIC DATA. HE FOCUSES ON DEVELOPING INSTRUMENTATION AND TECHNIQUES FOR HIGH SPATIAL RESOLUTION, HIGH SENSITIVITY PALEOMAGNETIC ANALYSES. HE WILL CARRY OUT THE MAGNETIC MICROSCOPY MEASUREMENTS AND THE SAMPLE PREPARATION ASSOCIATED WITH THE PALEOMAGNETIC STUDIES OF 10 – 12 SELECT SMALL BENNU PARTICLES USING ALTERNATING-FIELD METHODS AND SCANNING SUPERCONDUCTING QUANTUM INTERFERENCE DEVICE (SQUID) MICROSCOPY, WILL PROCESS THE DATA AND COMPUTE INVERSIONS TO ESTIMATE NET MAGNETIC MOMENT AND/OR MAGNETIZATION DISTRIBUTION, AND WILL ANALYZE AND INTERPRET THE RESULTS.

THE CALTECH SUB-TEAM OF THIS PARTICIPATING SCIENTIST PROPOSAL WILL PERFORM HIGH-RESOLUTION MAGNETIC STUDIES ON RETURNED SUB-SAMPLES OF ASTEROID BENNU. THEY WILL FIRST USE THE CLEAN LAB BASED SUPERCONDUCTING MAGNETIC MOMENT MAGNETOMETER TO MEASURE AND CHARACTERIZE THE REMANENT MAGNETIZATION (IF ANY) OF THE RETURNED MATERIALS, AND TO SCREEN FOR THE PRESENCE OF ANY NET MAGNETIC CHARGE (POSSIBLE DIRAC MAGNETIC MONOPOLES). THEY WILL THEN CONDUCT PALEOMAGNETIC CONGLOMERATE TESTS ON INTACT FRAGMENTS USING THEIR PULSE-TUBE BASED SCANNING SQUID-BASED MAGNETIC IMAGING SYSTEM ON SUITABLY FLAT SURFACES TO SEE IF SUB-PARTICLES WITHIN THE MATRIX OF THE BENNU ASTEROID WERE MAGNETIZED BEFORE OR AFTER INCORPORATION INTO THE PARENTAL MATERIALS. THEY WILL THEN, IN COLLABORATION WITH THE OTHER SUB-TEAMS OF THIS PARTICIPATING SCIENTIST PROGRAM, DEVISE AND HELP CONDUCT EXPERIMENTS TO CONSTRAIN THE PALEOINTENSITY OF THE MAGNETIC FIELDS PRESENT DURING THE FORMATION AND ACCRETION OF BENNU.

TO CONSTRAIN THE FORMATION AGE(S) OF THE MAGNETITE, WE WILL (I) IDENTIFY CO-PRECIPITATED MAGNETITE AND CARBONATES IN THE BENNU SAMPLES USING THE MINERALOGY, PETROGRAPHY (SCANNING ELECTRON MICROSCOPY (SEM), ELECTRON PROBE MICROANALYSIS (EPMA)), AND O-ISOTOPE COMPOSITIONS (SECONDARY ION MASS-SPECTROMETRY (SIMS) OF THESE MINERALS, AND (II) ANALYZE 53MN-53CR ISOTOPE SYSTEMATICS OF CARBONATES (SIMS). OXYGEN- AND MN-CR SYSTEMATICS OF MAGNETITE AND CARBONATES WOULD BE ALSO IMPORTANT FOR CONSTRAINING TEMPERATURE OF AQUEOUS ALTERATION AND AGE OF AQUEOUS ACTIVITY IN THE BENNU PARENT ASTEROID. ALL MEASUREMENTS WILL BE DONE BY DR. A. KROT USING JEOL JXA-8500F ELECTRON MICROPROBE AND CAMECA IMS-1280 SIMS. ALL THESE INSTRUMENTS ARE PRESENT AT THE UNIVERSITY OF HAWAI‘I AT MĀNOA AND WILL BE AVAILABLE FOR THE PROPOSED MEASUREMENTS IN 2022-2026.

SUBAWARD 91028280: $59,614.00 1/22/2018 STATEMENT OF WORK PI: CHRISTOPHER STUBBS HARVARD UNIVERSITY 01/01/2018 " 06/30/2018 TESTING GRAVITY VIA LUNAR LASER RANGING: MAXIMIZING DATA QUALITY DR. JOHN CHANDLER WILL WORK CLOSELY WITH THE APOLLO TEAM ON THE ANALYSIS OF THE LLR AND OTHER DATA, USING THE PLANETARY EPHEMERIS PROGRAM (PEP). THE TASKS INCLUDE: A) EVALUATING, UNDERSTANDING, AND MINIMIZING THE RESIDUALS BETWEEN THE DATA AND BEST-FIT MODELS, AND ADDING NEW PHENOMENOLOGY TO PEP AS APPROPRIATE; B) INCORPORATING AUXILIARY DATA INTO PEP; C) DEVELOPING AND IMPLEMENTING IMPROVED COMPUTATIONAL ALGORITHMS IN PEP AS THESE ARE IDENTIFIED IN RESPONSE TO PROJECT NEEDS; D) EXTENDING THE PEP ANALYSIS TO CONSTRAIN THEORIES OF NOVEL GRAVITATIONAL EFFECTS THAT DO NOT MAP NEATLY INTO THE PPN FORMALISM; AND E) ESTABLISHING QUANTITATIVE ASSESSMENTS OF SOURCES OF SYSTEMATIC ERROR.