SCIENCE GOALS/OBJECTIVES: THIS PROJECT IS AN INTERDISCIPLINARY EFFORT TO INVESTIGATE CARBON INHERITANCE IN THE EARLY SOLAR NEBULA. CARBON IS A KEY PREBIOTIC ELEMENT AND A MAJOR COMPONENT IN PROTOPLANETARY MATERIALS. THUS UNDERSTANDING THE EVOLUTION OF CARBON WILL HELP CONSTRAIN THE ASTROCHEMICAL ENVIRONMENT OF TERRESTRIAL PLANET FORMATION AND THE PRODUCTION OF PREBIOTIC COMPOUNDS IN THE EARLY SOLAR SYSTEM. THE SOLAR SYSTEM 12C/13C RATIO IS ~ 87 WHICH IS SIGNIFICANTLY HIGHER THAN THE 12C/13C OF THE SURROUNDING INTERSTELLAR MEDIUM (~ 69). FURTHER HIGH-RESOLUTION ASTRONOMICAL OBSERVATIONS TOWARD LOW-MASS YOUNG STELLAR OBJECTS (YSOS) HAVE REVEALED UNEXPECTED HETEROGENEITY IN GAS-PHASE [12C16O[/[13C16O] (HERETOFORE 12CO/13CO) SUGGESTING THAT COMPLEX CHEMISTRY MAY BE AFFECTING PROTOPLANETARY CARBON RATHER THAN SUGGESTED DIRECT INHERITANCE FROM THE PARENT CLOUD. THIS PROJECT AIMS TO EXPLAIN ISOTOPIC OBSERVATIONS TOWARD YSOS AND ACHIEVE A COMPREHENSIVE UNDERSTANDING OF THE UNDERLYING CHEMISTRY AFFECTING EARLY CARBON RESERVOIRS IN THE SOLAR NEBULA THROUGH THE FOLLOWING: (1) OBSERVATIONS -WE WILL ANALYZE HIGH-RESOLUTION CO DATA OF BRIGHT YSOS ALONG A GALACTIC GRADIENT OBSERVED WITH THE KECK TELESCOPE AND INFORMED BY ARCHIVED KECK AND CRIRES DATA. RATIOS OF [12CO]/[13CO] DERIVED FROM THE DATA WILL BE INTERPRETED IN THE CONTEXT OF 12C/13C FROM OTHER CARBON-BASED RESERVOIRS (I.E. CO AND CO2 ICE) THAT ARE ALONG THE SAME LINE-OF-SIGHT THEREBY ENABLING A DIRECT INVESTIGATION OF CARBON INHERITANCE IN EACH PROTOPLANETARY SYSTEM; (2) EXPERIMENTS - WE WILL PERFORM INTERSTELLAR ICE EXPERIMENTS TO EXPLORE CARBON FRACTIONATION PATHWAYS BETWEEN CO AND CO2 MOLECULAR RESERVOIRS FURTHER AIDING IN THE INTERPRETATION OF ASTRONOMICAL OBSERVATIONS; AND (3) MODELS - WE WILL CREATE THEORETICAL MODELS TO HELP PARAMETERIZE OBSERVED ISOTOPE RATIOS AND FURTHER DEFINE THE CHEMICAL PATHWAYS ALONG EACH LINE-OF-SIGHT TRACKING CHANGES IN THE CARBON-CONTAINING GAS AND ICE. OUR GOAL IS TO ADD SIGNIFICANTLY TO OUR UNDERSTANDING OF CARBON EVOLUTION IN THE EARLY SOLAR NEBULA AND HELP PUT THE SOLAR SYSTEM INTO A MEANINGFUL CONTEXT WITH RESPECT TO OTHER PROTOPLANETARY SYSTEMS. METHODOLOGY: HIGH-RESOLUTION ROVIBRATIONAL SPECTRA FROM NIRSPEC ON THE KECK TELESCOPE WILL BE USED TO DERIVE PRECISE ABUNDANCES FOR CO ISOTOPOLOGUES INCLUDING 12C18O AND 12C17O WHICH HELP CONSTRAIN THE ANALYSIS. OBSERVATIONS OF MASSIVE YSOS WILL BE LED BY THE PI AND COLLABORATOR BLAKE AND OUR CUSTOMIZED CODES WILL BE USED FOR DATA REDUCTION AND ANALYSIS OF NEW AND ARCHIVAL DATA. A SET OF NEW DATA WILL BE OBTAINED TO FILL IN MISSING REGIONS OF THE GALACTIC GRADIENT. ARCHIVAL DATA FROM THE CRIRES AND KECK ARCHIVES WILL BE USED TO HELP CONSTRAIN 13CO ABUNDANCES WHICH ARE USEFUL FOR INPUT INTO THE MODELS. CO-I GUDIPATI WILL LEAD THE EXPERIMENTS AT HIS JPL LAB WHICH IS EQUIPPED TO EXPLORE MOLECULAR RESERVOIRS AND POTENTIAL FRACTIONATION MECHANISMS BETWEEN ISOTOPOLOGUES OF CO AND CO2 IN ICE AND GAS PHASES UNDER RELEVANT INTERSTELLAR CONDITIONS. THE CO MODELS LED BY CO-I WILLACY WILL TRACK GAS AND ICE ISOTOPE CHEMISTRY IN A RANGE OF SYSTEMS AIMED AT EXPLORING CO ICE- AND GAS-RESERVOIRS USING APPROPRIATE PHYSICAL CONDITIONS. THE MODELS WILL DERIVE MOLECULAR ISOTOPE RATIOS ACROSS TEMPERATURE GRADIENTS IDENTIFIED FROM THE SPECTRAL ANALYSES. THE ENTIRE PROPOSAL TEAM WILL CONTRIBUTE TO THE SCIENCE AND THE PI WILL RECRUIT 3 STUDENTS/YEAR TO PARTICIPATE IN DEFINED ASPECTS OF THE PROJECT. RELEVANCE: THIS PROJECT IS RELEVANT TO MANY ASPECTS OF THE EMERGING WORLDS (EW) SCOPE INCLUDING INVESTIGATIONS OF PROCESSES THAT RESULT IN A SIGNIFICANT CHANGE TO THE CHEMICAL NATURE OF THE SOLAR SYSTEM AND ADDRESSES THE RELEVANT TOPICS OF PROTOPLANETARY DISK FORMATION AND EVOLUTION (VIA UNDERSTANDING THEIR PRIMORDIAL CORE PHASES) LARGE-SCALE ISOTOPIC FRACTIONATION PROCESSES AND CHEMICAL PROCESSING OF GAS AND ICE. FURTHER OUR STUDY IS RELEVANT TO THE EW ENCOURAGEMENT OF INTERDISCIPLINARY WORK.