Not listed SCIENCE GOALS AND OBJECTIVES: WE PROPOSE TO USE HIGH-RESOLUTION NEAR-IR GROUND-BASED SPECTROSCOPY TO DIRECTLY CHARACTERIZE NEPTUNE- AND JUPITER-SIZED EXOPLANETS THAT CLOSELY ORBIT THEIR HOST STARS. OUR SCIENTIFIC OBJECTIVES INCLUDE DIRECTLY MEASURING AT HIGH SPECTRAL RESOLUTION INDIVIDUAL MOLECULAR SPECIES (INCLUDING BUT NOT LIMITED TO H2O CO AND CH4) AND IN CONJUNCTION WITH RADIATIVE TRANSFER MODELS TO CONSTRAIN THE ATMOSPHERIC COMPOSITION TEMPERATURE PROFILE STRUCTURE AND ENERGY TRANSPORT. OUR METHODOLOGY DOES NOT REQUIRE THE PLANET TO TRANSIT AND THUS CAN ACCESS THE LARGE POPULATION OF NEARBY HOT-JUPITER SYSTEMS. THE DATA ALSO DIRECTLY MEASURE THE SEMI-AMPLITUDE RADIAL VELOCITY OF A PLANET'S ORBIT. FOR MULTI-PLANET SYSTEMS THIS INFORMS INVESTIGATIONS OF COPLANARITY. METHODOLOGY: WE HAVE AN ESTABLISHED GROUND-BASED OBSERVING CAMPAIGN THAT USES THE KECK NIRSPEC ECHELLE SPECTROGRAPH TO TARGET NEARBY CLOSE-IN PLANETS WITH HIGH-SPECTRAL RESOLUTION. OBSERVATIONS ARE TAKEN AT WAVELENGTHS FROM 2 - 5 MICRONS WHERE THE MOLECULES OF INTEREST (CO H2O CH4 ETC.) HAVE CLEARLY DISTINGUISHABLE FEATURES. OUR SPECTROSCOPY CAPTURES THE BLENDED LIGHT FROM A PLANET/ STAR SYSTEM ON MULTIPLE EPOCHS CORRESPONDING TO DIFFERENT ORBITAL PHASES AND ACHIEVES PHOTON SIGNAL-TO-NOISE LEVELS ON THE STELLAR LIGHT OF SEVERAL THOUSAND PER RESOLUTION ELEMENT PER EPOCH. THE INDIVIDUAL PLANET AND STAR SIGNALS ARE DISENTANGLED USING CROSSCORRELATION BASED TECHNIQUES WHICH LEVERAGE THE RADIAL VELOCITY OF A FAINT COMPANION TO SEPARATE IT FROM A BRIGHT HOST. WE UTILIZE HIGHLY CUSTOMIZED SYNTHETIC STELLAR AND PLANET SPECTRA AS TEMPLATES IN OUR CORRELATION ANALYSIS. BY ADJUSTING THE CHEMICAL AND PHYSICAL PARAMETERS OF THE PLANET SPECTRUM WE CAN INDEPENDENTLY PROBE DIFFERENT MOLECULAR SPECIES AND ATMOSPHERIC STRUCTURE. THIS APPROACH CAN MINIMIZE DEGENERACY IN THE PLANET MODELS THAT POSE SERIOUS PROBLEMS FOR MANY LOW-RESOLUTION AND PHOTOMETRIC STUDIES THAT HAVE OCCURRED OVER THE PAST DECADE. WE HAVE DEMONSTRATED THE VIABILITY OF OUR METHODOLOGY AND PUBLISHED A 3 MICRON DETECTION OF WATER VAPOR IN THE ATMOSPHERE OF THE HOT-JUPITER PLANET TAU BOOTIS B (LOCKWOOD ET AL. 2014 APJL 783 L29). IN ONGOING WORK WE HAVE ALSO FOUND THAT SUFFICIENT SIGNAL-TO-NOISE IN OUR WAVELENGTH REGIME CAN BE OBTAINED ON TARGETS WITH HOST STARS AS FAINT AS L~6.5 MAGNITUDES WHICH MAKES AVAILABLE A POPULATION OF MORE THAN A DOZEN KNOWN EXOPLANET SYSTEMS. SUBSTANTIAL NUMBERS OF ADDITIONAL TARGETS CAN BE EXPECTED FROM TESS AND ONGOING GROUND-BASED CAMPAIGNS. WE WILL ANALYZE THE OBSERVATIONAL DATA USING A NEWLY-DEVELOPED SELF-CONSISTENT ATMOSPHERIC RETRIEVAL FRAMEWORK SCARLET. UNLIKE PREVIOUS METHODS SCARLET COMBINES THE PHYSICAL AND CHEMICAL CONSISTENCY OF COMPLEX ATMOSPHERIC MODELS WITH THE STATISTICAL TREATMENT OF OBSERVATIONAL UNCERTAINTIES KNOWN FROM ATMOSPHERIC RETRIEVAL TECHNIQUES. IN PARTICULAR SCARLET WILL PERMIT US TO FULLY PROBE THE MULTIDIMENSIONAL PARAMETER SPACE SPANNED BY THE METALLICITY (THAT IS THE OVERALL ABUNDANCE OF HEAVY ELEMENTS) THE C/O RATIO AND PHYSICAL PROPERTIES SUCH THE INTERNAL HEAT SURFACE GRAVITY AND CLOUD FRACTION. RELEVANCE OF THE PROPOSED RESEARCH: THE PROPOSED RESEARCH IS HIGHLY RELEVANT TO THE EXOPLANETS RESEARCH PROGRAM GOAL OF: "UNDERSTANDING THE CHEMICAL AND PHYSICAL PROCESSES OF EXOPLANETS." DIRECT MEASUREMENTS OF MOLECULAR SPECIES IN THE ATMOSPHERES OF HOT GAS-GIANT EXOPLANETS STRONGLY CONSTRAIN THE OVERALL ATMOSPHERIC CHEMISTRY OF THESE OBJECTS AND ARE CRITICAL TOWARDS UNDERSTANDING BOTH THE ORIGINS AND SUBSEQUENT EVOLUTION OF PLANETARY SYSTEMS. ADDITIONALLY DIRECTLY DETECTING THE RADIAL VELOCITY SIGNATURES OF THESE PLANETS FACILITATES A DYNAMICAL MEASUREMENT OF THE TRUE PLANET MASS AND INFORMED ESTIMATES OF THE PLANET RADIUS BOTH OF WHICH ARE CRITICAL PROBES OF THE PHYSICAL PROCESSES AT WORK DURING PLANET FORMATION. ($22) 8/6/21 6 SCIENCE GOALS AND OBJECTIVES: WE PROPOSE TO USE HIGH-RESOLUTION, NEAR-IR, GROUND-BASED SPECTROSCOPY TO DIRECTLY CHARACTERIZE NEPTUNE- AND JUPITER-SIZED EXOPLANETS THAT CLOSELY ORBIT THEIR HOST STARS. OUR SCIENTIFIC OBJECTIVES INCLUDE DIRECTLY MEASURING, AT HIGH SPECTRAL RESOLUTION, INDIVIDUAL MOLECULAR SPECIES (INCLUDING, BUT NOT LIMITED TO, H2O, CO, AND CH4), AND, IN CONJUNCTION WITH RADIATIVE TRANSFER MODELS, TO CONSTRAIN THE ATMOSPHERIC COMPOSITION, TEMPERATURE PROFILE, STRUCTURE, AND ENERGY TRANSPORT. OUR METHODOLOGY DOES NOT REQUIRE THE PLANET TO TRANSIT, AND THUS CAN ACCESS THE LARGE POPULATION OF NEARBY HOT-JUPITER SYSTEMS. THE DATA ALSO DIRECTLY MEASURE THE SEMI-AMPLITUDE RADIAL VELOCITY OF A PLANET'S ORBIT. FOR MULTI-PLANET SYSTEMS, THIS INFORMS INVESTIGATIONS OF COPLANARITY. METHODOLOGY: WE HAVE AN ESTABLISHED GROUND-BASED OBSERVING CAMPAIGN THAT USES THE KECK NIRSPEC ECHELLE SPECTROGRAPH TO TARGET NEARBY CLOSE-IN PLANETS WITH HIGH-SPECTRAL RESOLUTION. OBSERVATIONS ARE TAKEN AT WAVELENGTHS FROM 2 - 5 MICRONS, WHERE THE MOLECULES OF INTEREST (CO, H2O, CH4, ETC.) HAVE CLEARLY DISTINGUISHABLE FEATURES. OUR SPECTROSCOPY CAPTURES THE BLENDED LIGHT FROM A PLANET/ STAR SYSTEM ON MULTIPLE EPOCHS, CORRESPONDING TO DIFFERENT ORBITAL PHASES, AND ACHIEVES PHOTON SIGNAL-TO-NOISE LEVELS ON THE STELLAR LIGHT OF SEVERAL THOUSAND PER RESOLUTION ELEMENT PER EPOCH. THE INDIVIDUAL PLANET AND STAR SIGNALS ARE DISENTANGLED USING CROSSCORRELATION BASED TECHNIQUES, WHICH LEVERAGE THE RADIAL VELOCITY OF A FAINT COMPANION TO SEPARATE IT FROM A BRIGHT HOST. WE UTILIZE HIGHLY CUSTOMIZED SYNTHETIC STELLAR AND PLANET SPECTRA AS TEMPLATES IN OUR CORRELATION ANALYSIS. BY ADJUSTING THE CHEMICAL AND PHYSICAL PARAMETERS OF THE PLANET SPECTRUM, WE CAN INDEPENDENTLY PROBE DIFFERENT MOLECULAR SPECIES AND ATMOSPHERIC STRUCTURE. THIS APPROACH CAN MINIMIZE DEGENERACY IN THE PLANET MODELS THAT POSE SERIOUS PROBLEMS FOR MANY LOW-RESOLUTION AND PHOTOMETRIC STUDIES THAT HAVE OCCURRED OVER THE PAST DECADE. WE HAVE DEMONSTRATED THE VIABILITY OF OUR METHODOLOGY AND PUBLISHED A 3 MICRON DETECTION OF WATER VAPOR IN THE ATMOSPHERE OF THE HOT-JUPITER PLANET TAU BOOTIS B (LOCKWOOD ET AL. 2014, APJL, 783, L29). IN ONGOING WORK WE HAVE ALSO FOUND THAT SUFFICIENT SIGNAL-TO-NOISE IN OUR WAVELENGTH REGIME CAN BE OBTAINED ON TARGETS WITH HOST STARS AS FAINT AS L~6.5 MAGNITUDES, WHICH MAKES AVAILABLE A POPULATION OF MORE THAN A DOZEN KNOWN EXOPLANET SYSTEMS. SUBSTANTIAL NUMBERS OF ADDITIONAL TARGETS CAN BE EXPECTED FROM TESS AND ONGOING GROUND-BASED CAMPAIGNS. WE WILL ANALYZE THE OBSERVATIONAL DATA USING A NEWLY-DEVELOPED, SELF-CONSISTENT ATMOSPHERIC RETRIEVAL FRAMEWORK, SCARLET. UNLIKE PREVIOUS METHODS, SCARLET COMBINES THE PHYSICAL AND CHEMICAL CONSISTENCY OF COMPLEX ATMOSPHERIC MODELS WITH THE STATISTICAL TREATMENT OF OBSERVATIONAL UNCERTAINTIES KNOWN FROM ATMOSPHERIC RETRIEVAL TECHNIQUES. IN PARTICULAR, SCARLET WILL PERMIT US TO FULLY PROBE THE MULTIDIMENSIONAL PARAMETER SPACE SPANNED BY THE METALLICITY (THAT IS, THE OVERALL ABUNDANCE OF HEAVY ELEMENTS), THE C/O RATIO, AND PHYSICAL PROPERTIES SUCH THE INTERNAL HEAT, SURFACE GRAVITY, AND CLOUD FRACTION. RELEVANCE OF THE PROPOSED RESEARCH: THE PROPOSED RESEARCH IS HIGHLY RELEVANT TO THE EXOPLANETS RESEARCH PROGRAM GOAL OF: "UNDERSTANDING THE CHEMICAL AND PHYSICAL PROCESSES OF EXOPLANETS." DIRECT MEASUREMENTS OF MOLECULAR SPECIES IN THE ATMOSPHERES OF HOT GAS-GIANT EXOPLANETS STRONGLY CONSTRAIN THE OVERALL ATMOSPHERIC CHEMISTRY OF THESE OBJECTS, AND ARE CRITICAL TOWARDS UNDERSTANDING BOTH THE ORIGINS AND SUBSEQUENT EVOLUTION OF PLANETARY SYSTEMS. ADDITIONALLY, DIRECTLY DETECTING THE RADIAL VELOCITY SIGNATURES OF THESE PLANETS FACILITATES A DYNAMICAL MEASUREMENT OF THE TRUE PLANET MASS AND INFORMED ESTIMATES OF THE PLANET RADIUS, BOTH OF WHICH ARE CRITICAL PROBES OF THE PHYSICAL PROCESSES AT WORK DURING PLANET FORMATION. Funding Only Action ($22) 8/6/21 5 SCIENCE GOALS AND OBJECTIVES: WE PROPOSE TO USE HIGH-RESOLUTION, NEAR-IR, GROUND-BASED SPECTROSCOPY TO DIRECTLY CHARACTERIZE NEPTUNE- AND JUPITER-SIZED EXOPLANETS THAT CLOSELY ORBIT THEIR HOST STARS. OUR SCIENTIFIC OBJECTIVES INCLUDE DIRECTLY MEASURING, AT HIGH SPECTRAL RESOLUTION, INDIVIDUAL MOLECULAR SPECIES (INCLUDING, BUT NOT LIMITED TO, H2O, CO, AND CH4), AND, IN CONJUNCTION WITH RADIATIVE TRANSFER MODELS, TO CONSTRAIN THE ATMOSPHERIC COMPOSITION, TEMPERATURE PROFILE, STRUCTURE, AND ENERGY TRANSPORT. OUR METHODOLOGY DOES NOT REQUIRE THE PLANET TO TRANSIT, AND THUS CAN ACCESS THE LARGE POPULATION OF NEARBY HOT-JUPITER SYSTEMS. THE DATA ALSO DIRECTLY MEASURE THE SEMI-AMPLITUDE RADIAL VELOCITY OF A PLANET'S ORBIT. FOR MULTI-PLANET SYSTEMS, THIS INFORMS INVESTIGATIONS OF COPLANARITY. METHODOLOGY: WE HAVE AN ESTABLISHED GROUND-BASED OBSERVING CAMPAIGN THAT USES THE KECK NIRSPEC ECHELLE SPECTROGRAPH TO TARGET NEARBY CLOSE-IN PLANETS WITH HIGH-SPECTRAL RESOLUTION. OBSERVATIONS ARE TAKEN AT WAVELENGTHS FROM 2 - 5 MICRONS, WHERE THE MOLECULES OF INTEREST (CO, H2O, CH4, ETC.) HAVE CLEARLY DISTINGUISHABLE FEATURES. OUR SPECTROSCOPY CAPTURES THE BLENDED LIGHT FROM A PLANET/ STAR SYSTEM ON MULTIPLE EPOCHS, CORRESPONDING TO DIFFERENT ORBITAL PHASES, AND ACHIEVES PHOTON SIGNAL-TO-NOISE LEVELS ON THE STELLAR LIGHT OF SEVERAL THOUSAND PER RESOLUTION ELEMENT PER EPOCH. THE INDIVIDUAL PLANET AND STAR SIGNALS ARE DISENTANGLED USING CROSSCORRELATION BASED TECHNIQUES, WHICH LEVERAGE THE RADIAL VELOCITY OF A FAINT COMPANION TO SEPARATE IT FROM A BRIGHT HOST. WE UTILIZE HIGHLY CUSTOMIZED SYNTHETIC STELLAR AND PLANET SPECTRA AS TEMPLATES IN OUR CORRELATION ANALYSIS. BY ADJUSTING THE CHEMICAL AND PHYSICAL PARAMETERS OF THE PLANET SPECTRUM, WE CAN INDEPENDENTLY PROBE DIFFERENT MOLECULAR SPECIES AND ATMOSPHERIC STRUCTURE. THIS APPROACH CAN MINIMIZE DEGENERACY IN THE PLANET MODELS THAT POSE SERIOUS PROBLEMS FOR MANY LOW-RESOLUTION AND PHOTOMETRIC STUDIES THAT HAVE OCCURRED OVER THE PAST DECADE. WE HAVE DEMONSTRATED THE VIABILITY OF OUR METHODOLOGY AND PUBLISHED A 3 MICRON DETECTION OF WATER VAPOR IN THE ATMOSPHERE OF THE HOT-JUPITER PLANET TAU BOOTIS B (LOCKWOOD ET AL. 2014, APJL, 783, L29). IN ONGOING WORK WE HAVE ALSO FOUND THAT SUFFICIENT SIGNAL-TO-NOISE IN OUR WAVELENGTH REGIME CAN BE OBTAINED ON TARGETS WITH HOST STARS AS FAINT AS L~6.5 MAGNITUDES, WHICH MAKES AVAILABLE A POPULATION OF MORE THAN A DOZEN KNOWN EXOPLANET SYSTEMS. SUBSTANTIAL NUMBERS OF ADDITIONAL TARGETS CAN BE EXPECTED FROM TESS AND ONGOING GROUND-BASED CAMPAIGNS. WE WILL ANALYZE THE OBSERVATIONAL DATA USING A NEWLY-DEVELOPED, SELF-CONSISTENT ATMOSPHERIC RETRIEVAL FRAMEWORK, SCARLET. UNLIKE PREVIOUS METHODS, SCARLET COMBINES THE PHYSICAL AND CHEMICAL CONSISTENCY OF COMPLEX ATMOSPHERIC MODELS WITH THE STATISTICAL TREATMENT OF OBSERVATIONAL UNCERTAINTIES KNOWN FROM ATMOSPHERIC RETRIEVAL TECHNIQUES. IN PARTICULAR, SCARLET WILL PERMIT US TO FULLY PROBE THE MULTIDIMENSIONAL PARAMETER SPACE SPANNED BY THE METALLICITY (THAT IS, THE OVERALL ABUNDANCE OF HEAVY ELEMENTS), THE C/O RATIO, AND PHYSICAL PROPERTIES SUCH THE INTERNAL HEAT, SURFACE GRAVITY, AND CLOUD FRACTION. RELEVANCE OF THE PROPOSED RESEARCH: THE PROPOSED RESEARCH IS HIGHLY RELEVANT TO THE EXOPLANETS RESEARCH PROGRAM GOAL OF: "UNDERSTANDING THE CHEMICAL AND PHYSICAL PROCESSES OF EXOPLANETS." DIRECT MEASUREMENTS OF MOLECULAR SPECIES IN THE ATMOSPHERES OF HOT GAS-GIANT EXOPLANETS STRONGLY CONSTRAIN THE OVERALL ATMOSPHERIC CHEMISTRY OF THESE OBJECTS, AND ARE CRITICAL TOWARDS UNDERSTANDING BOTH THE ORIGINS AND SUBSEQUENT EVOLUTION OF PLANETARY SYSTEMS. ADDITIONALLY, DIRECTLY DETECTING THE RADIAL VELOCITY SIGNATURES OF THESE PLANETS FACILITATES A DYNAMICAL MEASUREMENT OF THE TRUE PLANET MASS AND INFORMED ESTIMATES OF THE PLANET RADIUS, BOTH OF WHICH ARE CRITICAL PROBES OF THE PHYSICAL PROCESSES AT WORK DURING PLANET FORMATION. Other Administrative Action $0 3/20/20 Not listed SCIENCE GOALS AND OBJECTIVES: WE PROPOSE TO USE HIGH-RESOLUTION NEAR-IR GROUND-BASED SPECTROSCOPY TO DIRECTLY CHARACTERIZE NEPTUNE- AND JUPITER-SIZED EXOPLANETS THAT CLOSELY ORBIT THEIR HOST STARS. OUR SCIENTIFIC OBJECTIVES INCLUDE DIRECTLY MEASURING AT HIGH SPECTRAL RESOLUTION INDIVIDUAL MOLECULAR SPECIES (INCLUDING BUT NOT LIMITED TO H2O CO AND CH4) AND IN CONJUNCTION WITH RADIATIVE TRANSFER MODELS TO CONSTRAIN THE ATMOSPHERIC COMPOSITION TEMPERATURE PROFILE STRUCTURE AND ENERGY TRANSPORT. OUR METHODOLOGY DOES NOT REQUIRE THE PLANET TO TRANSIT AND THUS CAN ACCESS THE LARGE POPULATION OF NEARBY HOT-JUPITER SYSTEMS. THE DATA ALSO DIRECTLY MEASURE THE SEMI-AMPLITUDE RADIAL VELOCITY OF A PLANET'S ORBIT. FOR MULTI-PLANET SYSTEMS THIS INFORMS INVESTIGATIONS OF COPLANARITY. METHODOLOGY: WE HAVE AN ESTABLISHED GROUND-BASED OBSERVING CAMPAIGN THAT USES THE KECK NIRSPEC ECHELLE SPECTROGRAPH TO TARGET NEARBY CLOSE-IN PLANETS WITH HIGH-SPECTRAL RESOLUTION. OBSERVATIONS ARE TAKEN AT WAVELENGTHS FROM 2 - 5 MICRONS WHERE THE MOLECULES OF INTEREST (CO H2O CH4 ETC.) HAVE CLEARLY DISTINGUISHABLE FEATURES. OUR SPECTROSCOPY CAPTURES THE BLENDED LIGHT FROM A PLANET/ STAR SYSTEM ON MULTIPLE EPOCHS CORRESPONDING TO DIFFERENT ORBITAL PHASES AND ACHIEVES PHOTON SIGNAL-TO-NOISE LEVELS ON THE STELLAR LIGHT OF SEVERAL THOUSAND PER RESOLUTION ELEMENT PER EPOCH. THE INDIVIDUAL PLANET AND STAR SIGNALS ARE DISENTANGLED USING CROSSCORRELATION BASED TECHNIQUES WHICH LEVERAGE THE RADIAL VELOCITY OF A FAINT COMPANION TO SEPARATE IT FROM A BRIGHT HOST. WE UTILIZE HIGHLY CUSTOMIZED SYNTHETIC STELLAR AND PLANET SPECTRA AS TEMPLATES IN OUR CORRELATION ANALYSIS. BY ADJUSTING THE CHEMICAL AND PHYSICAL PARAMETERS OF THE PLANET SPECTRUM WE CAN INDEPENDENTLY PROBE DIFFERENT MOLECULAR SPECIES AND ATMOSPHERIC STRUCTURE. THIS APPROACH CAN MINIMIZE DEGENERACY IN THE PLANET MODELS THAT POSE SERIOUS PROBLEMS FOR MANY LOW-RESOLUTION AND PHOTOMETRIC STUDIES THAT HAVE OCCURRED OVER THE PAST DECADE. WE HAVE DEMONSTRATED THE VIABILITY OF OUR METHODOLOGY AND PUBLISHED A 3 MICRON DETECTION OF WATER VAPOR IN THE ATMOSPHERE OF THE HOT-JUPITER PLANET TAU BOOTIS B (LOCKWOOD ET AL. 2014 APJL 783 L29). IN ONGOING WORK WE HAVE ALSO FOUND THAT SUFFICIENT SIGNAL-TO-NOISE IN OUR WAVELENGTH REGIME CAN BE OBTAINED ON TARGETS WITH HOST STARS AS FAINT AS L~6.5 MAGNITUDES WHICH MAKES AVAILABLE A POPULATION OF MORE THAN A DOZEN KNOWN EXOPLANET SYSTEMS. SUBSTANTIAL NUMBERS OF ADDITIONAL TARGETS CAN BE EXPECTED FROM TESS AND ONGOING GROUND-BASED CAMPAIGNS. WE WILL ANALYZE THE OBSERVATIONAL DATA USING A NEWLY-DEVELOPED SELF-CONSISTENT ATMOSPHERIC RETRIEVAL FRAMEWORK SCARLET. UNLIKE PREVIOUS METHODS SCARLET COMBINES THE PHYSICAL AND CHEMICAL CONSISTENCY OF COMPLEX ATMOSPHERIC MODELS WITH THE STATISTICAL TREATMENT OF OBSERVATIONAL UNCERTAINTIES KNOWN FROM ATMOSPHERIC RETRIEVAL TECHNIQUES. IN PARTICULAR SCARLET WILL PERMIT US TO FULLY PROBE THE MULTIDIMENSIONAL PARAMETER SPACE SPANNED BY THE METALLICITY (THAT IS THE OVERALL ABUNDANCE OF HEAVY ELEMENTS) THE C/O RATIO AND PHYSICAL PROPERTIES SUCH THE INTERNAL HEAT SURFACE GRAVITY AND CLOUD FRACTION. RELEVANCE OF THE PROPOSED RESEARCH: THE PROPOSED RESEARCH IS HIGHLY RELEVANT TO THE EXOPLANETS RESEARCH PROGRAM GOAL OF: "UNDERSTANDING THE CHEMICAL AND PHYSICAL PROCESSES OF EXOPLANETS." DIRECT MEASUREMENTS OF MOLECULAR SPECIES IN THE ATMOSPHERES OF HOT GAS-GIANT EXOPLANETS STRONGLY CONSTRAIN THE OVERALL ATMOSPHERIC CHEMISTRY OF THESE OBJECTS AND ARE CRITICAL TOWARDS UNDERSTANDING BOTH THE ORIGINS AND SUBSEQUENT EVOLUTION OF PLANETARY SYSTEMS. ADDITIONALLY DIRECTLY DETECTING THE RADIAL VELOCITY SIGNATURES OF THESE PLANETS FACILITATES A DYNAMICAL MEASUREMENT OF THE TRUE PLANET MASS AND INFORMED ESTIMATES OF THE PLANET RADIUS BOTH OF WHICH ARE CRITICAL PROBES OF THE PHYSICAL PROCESSES AT WORK DURING PLANET FORMATION. $0 3/20/20 4 SCIENCE GOALS AND OBJECTIVES: WE PROPOSE TO USE HIGH-RESOLUTION, NEAR-IR, GROUND-BASED SPECTROSCOPY TO DIRECTLY CHARACTERIZE NEPTUNE- AND JUPITER-SIZED EXOPLANETS THAT CLOSELY ORBIT THEIR HOST STARS. OUR SCIENTIFIC OBJECTIVES INCLUDE DIRECTLY MEASURING, AT HIGH SPECTRAL RESOLUTION, INDIVIDUAL MOLECULAR SPECIES (INCLUDING, BUT NOT LIMITED TO, H2O, CO, AND CH4), AND, IN CONJUNCTION WITH RADIATIVE TRANSFER MODELS, TO CONSTRAIN THE ATMOSPHERIC COMPOSITION, TEMPERATURE PROFILE, STRUCTURE, AND ENERGY TRANSPORT. OUR METHODOLOGY DOES NOT REQUIRE THE PLANET TO TRANSIT, AND THUS CAN ACCESS THE LARGE POPULATION OF NEARBY HOT-JUPITER SYSTEMS. THE DATA ALSO DIRECTLY MEASURE THE SEMI-AMPLITUDE RADIAL VELOCITY OF A PLANET'S ORBIT. FOR MULTI-PLANET SYSTEMS, THIS INFORMS INVESTIGATIONS OF COPLANARITY. METHODOLOGY: WE HAVE AN ESTABLISHED GROUND-BASED OBSERVING CAMPAIGN THAT USES THE KECK NIRSPEC ECHELLE SPECTROGRAPH TO TARGET NEARBY CLOSE-IN PLANETS WITH HIGH-SPECTRAL RESOLUTION. OBSERVATIONS ARE TAKEN AT WAVELENGTHS FROM 2 - 5 MICRONS, WHERE THE MOLECULES OF INTEREST (CO, H2O, CH4, ETC.) HAVE CLEARLY DISTINGUISHABLE FEATURES. OUR SPECTROSCOPY CAPTURES THE BLENDED LIGHT FROM A PLANET/ STAR SYSTEM ON MULTIPLE EPOCHS, CORRESPONDING TO DIFFERENT ORBITAL PHASES, AND ACHIEVES PHOTON SIGNAL-TO-NOISE LEVELS ON THE STELLAR LIGHT OF SEVERAL THOUSAND PER RESOLUTION ELEMENT PER EPOCH. THE INDIVIDUAL PLANET AND STAR SIGNALS ARE DISENTANGLED USING CROSSCORRELATION BASED TECHNIQUES, WHICH LEVERAGE THE RADIAL VELOCITY OF A FAINT COMPANION TO SEPARATE IT FROM A BRIGHT HOST. WE UTILIZE HIGHLY CUSTOMIZED SYNTHETIC STELLAR AND PLANET SPECTRA AS TEMPLATES IN OUR CORRELATION ANALYSIS. BY ADJUSTING THE CHEMICAL AND PHYSICAL PARAMETERS OF THE PLANET SPECTRUM, WE CAN INDEPENDENTLY PROBE DIFFERENT MOLECULAR SPECIES AND ATMOSPHERIC STRUCTURE. THIS APPROACH CAN MINIMIZE DEGENERACY IN THE PLANET MODELS THAT POSE SERIOUS PROBLEMS FOR MANY LOW-RESOLUTION AND PHOTOMETRIC STUDIES THAT HAVE OCCURRED OVER THE PAST DECADE. WE HAVE DEMONSTRATED THE VIABILITY OF OUR METHODOLOGY AND PUBLISHED A 3 MICRON DETECTION OF WATER VAPOR IN THE ATMOSPHERE OF THE HOT-JUPITER PLANET TAU BOOTIS B (LOCKWOOD ET AL. 2014, APJL, 783, L29). IN ONGOING WORK WE HAVE ALSO FOUND THAT SUFFICIENT SIGNAL-TO-NOISE IN OUR WAVELENGTH REGIME CAN BE OBTAINED ON TARGETS WITH HOST STARS AS FAINT AS L~6.5 MAGNITUDES, WHICH MAKES AVAILABLE A POPULATION OF MORE THAN A DOZEN KNOWN EXOPLANET SYSTEMS. SUBSTANTIAL NUMBERS OF ADDITIONAL TARGETS CAN BE EXPECTED FROM TESS AND ONGOING GROUND-BASED CAMPAIGNS. WE WILL ANALYZE THE OBSERVATIONAL DATA USING A NEWLY-DEVELOPED, SELF-CONSISTENT ATMOSPHERIC RETRIEVAL FRAMEWORK, SCARLET. UNLIKE PREVIOUS METHODS, SCARLET COMBINES THE PHYSICAL AND CHEMICAL CONSISTENCY OF COMPLEX ATMOSPHERIC MODELS WITH THE STATISTICAL TREATMENT OF OBSERVATIONAL UNCERTAINTIES KNOWN FROM ATMOSPHERIC RETRIEVAL TECHNIQUES. IN PARTICULAR, SCARLET WILL PERMIT US TO FULLY PROBE THE MULTIDIMENSIONAL PARAMETER SPACE SPANNED BY THE METALLICITY (THAT IS, THE OVERALL ABUNDANCE OF HEAVY ELEMENTS), THE C/O RATIO, AND PHYSICAL PROPERTIES SUCH THE INTERNAL HEAT, SURFACE GRAVITY, AND CLOUD FRACTION. RELEVANCE OF THE PROPOSED RESEARCH: THE PROPOSED RESEARCH IS HIGHLY RELEVANT TO THE EXOPLANETS RESEARCH PROGRAM GOAL OF: "UNDERSTANDING THE CHEMICAL AND PHYSICAL PROCESSES OF EXOPLANETS." DIRECT MEASUREMENTS OF MOLECULAR SPECIES IN THE ATMOSPHERES OF HOT GAS-GIANT EXOPLANETS STRONGLY CONSTRAIN THE OVERALL ATMOSPHERIC CHEMISTRY OF THESE OBJECTS, AND ARE CRITICAL TOWARDS UNDERSTANDING BOTH THE ORIGINS AND SUBSEQUENT EVOLUTION OF PLANETARY SYSTEMS. ADDITIONALLY, DIRECTLY DETECTING THE RADIAL VELOCITY SIGNATURES OF THESE PLANETS FACILITATES A DYNAMICAL MEASUREMENT OF THE TRUE PLANET MASS AND INFORMED ESTIMATES OF THE PLANET RADIUS, BOTH OF WHICH ARE CRITICAL PROBES OF THE PHYSICAL PROCESSES AT WORK DURING PLANET FORMATION. Other Administrative Action $0 1/21/20