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2015 Annual Science Report

NASA Goddard Space Flight Center Reporting  |  JAN 2015 – DEC 2015

Executive Summary

The Goddard Team addresses this central question: Did delivery of exogenous organics and water enable the emergence and evolution of life? In short: Why is Earth wet and alive? Along with the origin of Earth’s water, we seek to better understand which organic compounds are generated in the interstellar and proto-planetary environments and later delivered to planets. We address this goal through observational, theoretical, and laboratory work.

Our investigations embody an integrated program of (a) pan-spectral astronomical observations of comets, circumstellar disks, and exoplanet environments, (b) models of dynamical transport in the early Solar System, (c) laboratory studies of extraterrestrial samples, and (d) realistic laboratory and numerical simulations of inaccessible cosmic environments. Synergistic integration of these areas is essential for testing whether delivery of the building blocks of life – exogenous water and prebiotic organics – enabled the emergence and development of the biosphere. In this ... Continue reading.

Field Sites
28 Institutions
12 Project Reports
38 Publications
19 Field Sites
Roadmap
Objectives

Project Reports

  • Circumstellar Debris and Planetesimals in Exoplanetary Systems

    GCA astronomer Marc Kuchner studies the dynamics of debris disks, extrasolar analogs to the Kuiper Belt and the asteroid belt in our solar system, using NASA’s supercomputers. He develops numerical models of the orbits and the interactions of the planetesimals in these disks for use in interpreting images of them made with the Hubble Telescope and other NASA observatories. Together, the images and models teach us about how planetary systems form and evolve – the context within which processes affecting our Solar System are evaluated and extended to exo-planetary systems. An important goal is to extend these studies to a wider range of proto-planetary systems, thereby expanding the range of diversity within which the Solar System must be interpreted. Kuchner’s second initiative targets that objective.

    Accordingly, Kuchner invited the public to help him discover new planetary systems through a new website, launched in 2014. At DiskDetective.org, volunteers view data from NASA’s Wide-field Infrared Survey Explorer (WISE) mission and three other surveys. WISE measured more than 745 million objects, representing the most comprehensive survey of the sky at mid-infrared wavelengths ever taken. Among these objects, thousands of planetary systems await discovery – recognizable by the dusty disks that surround them. But galaxies, interstellar dust clouds and asteroids also glow in the infrared, which stymies automated efforts to identify these disks. At Disk Detective.org, the volunteers find the disks by watching 10-second videos of objects seen by WISE, then classifying them by clicking on a selection of buttons on their screens.

    ROADMAP OBJECTIVES: 1.1 1.2
  • Surface Mediated Reactions in the Primitive Solar Nebula

    Hydrogen, carbon monoxide and nitrogen gases are abundant in the primitive solar nebula, as are silicate dust and metallic grains. These gases can react on such grain surfaces to produce an abundance of carbon-bearing products that include volatile hydrocarbons, amines, alcohols, aldehydes and acids as well as more complex, less volatile species such as carbon nanotubes. Refractory carbonaceous deposits catalyze additional surface reactions. Nebular environments span a large range in time, temperature, pressure, catalyst composition and secondary reactions. We are working to understand the rates and products of such reactions that could occur in nebular environments.

    ROADMAP OBJECTIVES: 1.1 3.1
  • NNX15AT33A Origin and Evolution of Organics and Water in Planetary Systems

    Research by the Blake group (CalTech) supported by the NAI has centered on a joint laboratory and observational program, designed with the participation of Goddard node scientists, that aims to investigate the chemistry of water and simple organics in the protoplanetary disk analogs of the early solar nebula, in comets, and in the atmospheres of extrasolar planets. The laboratory work has involved the creation of novel high bandwidth instruments from the microwave to the THz regime that can probe both gaseous and condensed phase (liquid and solid) materials. Particular emphasis has been placed on the study of small chiral (that is, ‘handed’) organic species, with a view toward establishing whether the homochirality exhibited on the Earth is stochastically or deterministically derived. We combine the laboratory studies with astronomical observations at radio (VLA, GBT, ALMA), far-infrared (SOFIA, Herschel archival data), and infrared (Keck/VLT, Spitzer archival data) wavelengths. A recent highlight is the first detection of a chiral species toward the Galactic Center, as is described in this report

    ROADMAP OBJECTIVES: 1.1 1.2 3.1
  • Laboratory Investigations Into Chemical Evolution in Icy Solids: Mars, Carbonaceous Meteorites, and ISM

    The goal of this project is to investigate chemical and physical changes and properties of molecules in low-temperature environments, such as found in interstellar space and the outer regions of the Solar System. Some of the molecules studied have been detected in meteorites and samples returned from NASA missions.

    ROADMAP OBJECTIVES: 2.1 2.2 3.1
  • Interstellar and Nebular Chemistry: Theory and Observations

    We continue to undertake theoretical and observational studies pertaining to the origin and evolution of organics in Planetary Systems, including the Solar System. In this performance period, we have focused on studies aimed at understanding the origin and processing of organics in the earliest evolutionary phases of stars like the Sun. These include formation pathways and related isotopic fractionation effects.

    We have continued observational programs designed to explore the chemical composition of comets and establishing their potential for delivering prebiotic organic materials and water to the young Earth and other planets. State-of-the-art international facilities are being employed to conduct multi-wavelength simultaneous studies of comets in order to gain more accurate abundances, distributions, temperatures, and other physical parameters of various cometary species. We are also leading an international collaboration to study the organic composition of Titan with the Atacama Large Millimeter Array (ALMA).

    ROADMAP OBJECTIVES: 1.1 1.2 2.2 3.1 3.2 7.1 7.2
  • Analytical Protocols and Techniques for Detection and Quantitative Analysis of Complex Organics in Planetary Environments

    Robotic planetary missions enable critical in situ investigations into the character, diversity and distribution of organic compounds in their native environments. The next-generation mass spectrometers being developed for planetary exploration promise enhanced capabilities to elucidate the molecular structure of detected organic compounds via tandem mass spectrometry (MS/MS), and to disambiguate potential biosignatures via ultra high-resolution mass discrimination. The in situ detection and potential sequencing of individual organic polymers using synthetic trans-membrane nanopores is another example of an innovative technology geared towards the identification of key organic compounds. We are engaged in evaluating and extending such innovative technologies to address astrobiological initiatives on future NASA missions.

    ROADMAP OBJECTIVES: 2.1 2.2 7.1
  • Undergraduate Research Associates in Astrobiology (URAA)

    2015 saw the twelfth session of our summer program for talented science students (Under-graduate Research Associates in Astrobiology), a ten-week residential research program tenured at Goddard Space Flight Center and the University of Maryland, College Park (http://astrobiology.gsfc.nasa.gov/education.html). Competition was again very keen, with an over-subscription ratio of 4.7. Students applied from over 19 Colleges and Universities in the United States, and 4 Interns from 4 institutions were selected. Each Intern carried out a defined research project working directly with a GCA scientist at Goddard Space Flight Center or the University of Maryland. As a group, the Associates met with a different GCA scientist each week, learning about his/her respective area of research, visiting diverse laboratories and gaining a broader view of astrobiology as a whole. At summer’s end, each Associate reported his/her research in a power point presentation projected nation-wide to member Teams in NASA’s Astrobiology Institute, as part of the NAI Forum for Astrobiology Research (FAR) Series.

    ROADMAP OBJECTIVES: 1.1 1.2 2.1 2.2 3.1 6.2 7.1
  • Serial Measurements of the Volatile Composition of Comet D/2012 S1 (ISON) between 1.2 and 0.34 AU from the Sun

    The composition of ices and rocky material in cometary nuclei is central to understanding their origins, and to assessing their possible roles in delivering water and prebiotic organic compounds to the young Earth. For most comets, measurements of primary volatiles (ices contained in the cometary nucleus) exist for only a single date or for very few dates, questioning whether such ‘momentary’ measurements represent the bulk content of the nucleus. The early discovery of the dynamically new, sun-grazing comet C/2012 S1 (ISON) was extremely rare in that it permitted measurements of the abundances of sublimed ices over a large range of heliocentric distance (Rh). As part of a world-wide observing campaign, world-class astronomical observatories provided large amounts of observing time dedicated to studying Comet ISON. Using high-resolution infrared spectroscopy at Keck-2 and the NASA-IRTF, the GCA Team measured production rates for H2O and eight trace gases (CO, C2H6, CH4, CH3OH, NH3, H2CO, HCN, C2H2) on ten pre-perihelion dates that spanned heliocentric distances ranging from 1.21 to 0.34 AU. This project addressed the evolution in molecular production and composition as the comet approached the Sun. GCA members also investigated the spatial distribution of H2O in the near-nucleus coma to identify modes of water release and of heat injection by release from icy grains, and they conducted a sensitive search for HDO to test the potential delivery of Earth’s oceans by such comets.

    ROADMAP OBJECTIVES: 3.1 3.2
  • Exploring the Structure and Composition of Exoplanets With Current and Future Telescopes

    This project addresses a major frontier of planetary science and astrobiology, namely the identification and characterization of habitable (and inhabited) exoplanets. Measurements of molecular absorption in the atmospheres of these planets offer the chance to explore several outstanding questions regarding the atmospheric structure and composition of hot Jupiters. Targeted questions include the possibility of bulk compositional variations among planets, and the presence or absence of a stratospheric temperature inversion on individual planets. In this reporting period, we emphasized four areas:
    1. We improved our modeling and analysis of exoplanet transit and eclipse measurements obtained with the Hubble Space Telescope (HST) and the Spitzer Space Telescope on highly irradiated, Jupiter-mass planets.
    2. We improved our data analysis methods to better understand aspects of measuring the chemical composition of the planet’s atmosphere, and we advanced the chemical and thermal modeling of the planet’s hot dayside.
    3. We developed simulations of future observations with the James Webb Space Telescope (JWST), and we provided science leadership for a future balloon-borne telescope that can perform transit spectroscopy of hot exoplanet atmospheres.
    4. We estimated the discovery yield of future Earth-like exoplanet imaging missions as part of the planning process for the next Astrophysics Decadal Survey, and we are now expanding this effort to estimate the science yield from spectroscopic characterization of them.

    ROADMAP OBJECTIVES: 1.1 1.2 7.2
  • Exploring the Evolution of the Water and Organic Reservoirs in the Solar System

    This project investigates the evolution and stability of water and organic reservoirs in our Solar System, with particular emphasis on the characterization of the current and ancient habitability of planet Mars. We employ extremely powerful observatories (e.g., ALMA, Keck, VLT, future JWST) to acquire high spatial and spectral resolution maps of the isotopic and organic signatures on several bodies in the Solar System. These maps allow us to investigate the stability and evolution of their atmospheres, while localized plumes can be used to identify regions of active release. In this reporting period, we emphasized three areas:

    1. We advanced our pioneering work on characterizing the evolution of water on Mars, by developing a new observational plan that combines the power of ALMA, of Keck and of MAVEN to obtain maps of the water D/H signatures on Mars.

    2. We identified previously unknown chemical processes affecting singlet-O2 and odd-oxygen on Mars, which may be indicative of a much more active photochemical cycle (with the possible intervention of heterogeneous processes).

    3. We provided science leadership in the investigation of Mars with the James Webb Space Telescope (JWST), and established a variety of observing modes and scientific opportunities.

    ROADMAP OBJECTIVES: 1.1 2.1 3.1 3.2 4.1 7.1
  • Evolution of Protoplanetary Disks and Preparations for Future Observations of Habitable Worlds

    The evolution of protoplanetary disks tells the story of the birth of planets and the formation of habitable environments. Microscopic interstellar materials are built up into larger and larger bodies, eventually forming planetesimals that are the building blocks of terrestrial planets and their atmospheres. With the advent of ALMA and continuing use of the Hubble Space Telescope, we are poised to break open the study of young exo-planetesimals, probing their organic content with detailed observations comparable to those obtained for Solar System bodies. Furthermore, studies of planetesimal debris around nearby mature stars are paving the way for future NASA missions to directly observe potentially habitable exoplanets.

    ROADMAP OBJECTIVES: 1.1 1.2 3.1 7.2
  • Analysis of Prebiotic Organic Compounds in Astrobiologically Relevant Samples

    The Astrobiology Analytical Laboratory (AAL) of the GCA is dedicated to the study of organic compounds derived from past and future sample return missions, meteorites, lab simulations of Mars, interstellar, proto-planetary, and cometary ices and grains, and instrument development. This year, we continued our work analyzing the organic content of carbonaceous chondrites, including analyses of amino acids, aliphatic amines, aldehydes and ketones. We investigated model systems for potentially relevant prebiotic chemistry. We supported the Biomolecule Sequencer project for evaluating DNA-analysis in microgravity environments by flying a MinIon device on the International Space Station. We continued to support development of protocols for a liquid chromatograph-mass spectrometer aimed at in situ analyses of amino acids and chirality on airless bodies, including asteroids and outer-planet icy moons (e.g., Enceladus and Europa). We participated in numerous public outreach and education events. We continued our participation in the OSIRIS-REx asteroid sample return mission and provided support for the Sample Analysis at Mars instrument of NASA’s Mars rover Curiosity.

    ROADMAP OBJECTIVES: 2.1 3.1

Publications

  • Miles, B. E., Roberge, A., & Welsh, B. (2016). UV SPECTROSCOPY OF STAR-GRAZING COMETS WITHIN THE 49 CETI DEBRIS DISK. The Astrophysical Journal, 824(2), 126. doi:10.3847/0004-637x/824/2/126

  • Angerhausen, D., Mandushev, G., Mandell, A., Dunham, E., Becklin, E., Collins, P., … Wolf, J. (2015). First exoplanet transit observation with the Stratospheric Observatory For Infrared Astronomy: confirmation of Rayleigh scattering in HD 189733 b with the High-Speed Imaging Photometer for Occultations. Journal of Astronomical Telescopes, Instruments, and Systems, 1(3), 034002. doi:10.1117/1.jatis.1.3.034002

  • Aponte, J. C., Dworkin, J. P., & Elsila, J. E. (2015). Indigenous aliphatic amines in the aqueously altered Orgueil meteorite. Meteoritics & Planetary Science, 50(10), 1733–1749. doi:10.1111/maps.12507

  • Biller, B. A., Liu, M. C., Rice, K., Wahhaj, Z., Nielsen, E., Hayward, T., … Toomey, D. W. (2015). The Gemini NICI Planet-Finding Campaign: asymmetries in the HD 141569 disc. Monthly Notices of the Royal Astronomical Society, 450(4), 4446–4457. doi:10.1093/mnras/stv870
  • Biver, N., Bockelée-Morvan, D., Moreno, R., Crovisier, J., Colom, P., Lis, D. C., … Milam, S. N. (2015). Ethyl alcohol and sugar in comet C/2014 Q2 (Lovejoy). Science Advances, 1(9), e1500863–e1500863. doi:10.1126/sciadv.1500863
  • Bockelée-Morvan, D., Calmonte, U., Charnley, S., Duprat, J., Engrand, C., Gicquel, A., … Wirström, E. (2015). Cometary isotopic measurements. Space Sci Rev, 197(1-4), 47–83. doi:10.1007/s11214-015-0156-9
  • Burton, A. S., McLain, H., Glavin, D. P., Elsila, J. E., Davidson, J., Miller, K. E., … Dworkin, J. P. (2015). Amino acid analyses of R and CK Chondrites. Meteoritics & Planetary Science, 50(3), 470–482. doi:10.1111/maps.12433
  • Cochran, A. L., Levasseur-Regourd, A-C., Cordiner, M., Hadamcik, E., Lasue, J., Gicquel, A., … Kuan, Y-J. (2015). The composition of Comets. Space Sci Rev, 197(1-4), 9–46. doi:10.1007/s11214-015-0183-6
  • Cordiner, M. A., Palmer, M. Y., Nixon, C. A., Irwin, P. G. J., Teanby, N. A., Charnley, S. B., … Wang, K-S. (2015). Ethyl cyanide on Titan: Spectroscopic detection and mapping Using ALMA. The Astrophysical Journal, 800(1), L14. doi:10.1088/2041-8205/800/1/l14
  • Currie, T., Cloutier, R., Brittain, S., Grady, C., Burrows, A., Muto, T., … Kuchner, M. J. (2015). Resolving the HD 100546 Protoplanetary system with the Gemini Planet Imager: Evidence for multiple forming and accreting Planets. The Astrophysical Journal, 814(2), L27.doi:10.1088/2041-8205/814/2/l27
  • Currie, T., Lisse, C. M., Kuchner, M., Madhusudhan, N., Kenyon, S. J., Thalmann, C., … Debes, J. (2015). Direct imaging and spectroscopy of a Young Extrasolar Kuiper Belt in the nearest OB Association. The Astrophysical Journal, 807(1), L7. doi:10.1088/2041-8205/807/1/l7
  • DiSanti, M.A., Bonev, B. P., Gibb, E. L., Paganini, L., Villanueva, G. L., Mumma, M. J., et al. (2016). En route to destruction: The evolution in composition of ices in Comet D/2012 S1 (ISON) between 1.2 and 0.34 AU from the Sun as revealed at infrared wavelengths. Volume 820, Number .1 Astrophysical J.
  • Elsila, J. E., Callahan, M. P., Dworkin, J. P., Glavin, D. P., McLain, H. L., Noble, S. K., & Gibson, E. K. (2016). The origin of amino acids in Lunar Regolith samples. Geochimica et Cosmochimica Acta, 172, 357–369. doi:10.1016/j.gca.2015.10.008
  • Freissinet, C., Glavin, D. P., Mahaffy, P. R., Miller, K. E., Eigenbrode, J. L., Summons, R. E., … Zorzano, M-P. (2015). Organic molecules in the Sheepbed Mudstone, Gale Crater, Mars. Journal of Geophysical Research: Planets, 120(3), 495–514. doi:10.1002/2014je004737
  • Friedrich, J. M., Glavin, D. P., Rivers, M. L., & Dworkin, J. P. (2016). Effect of a synchrotron X-ray microtomography imaging experiment on the amino acid content of a CM Chondrite. Meteoritics & Planetary Science, 51(2), 429–437. doi:10.1111/maps.12595
  • Gerakines, P. A., & Hudson, R. L. (2015). First infrared band strengths for amorphous CO2, an overlooked component of interstellar ices. The Astrophysical Journal, 808(2), L40. doi:10.1088/2041-8205/808/2/l40
  • Gerakines, P. A., & Hudson, R. L. (2015). Infrared spectra and optical constants of elusive amorphous methane. The Astrophysical Journal, 805(2), L20. doi:10.1088/2041-8205/805/2/l20
  • Gerakines, P. A., & Hudson, R. L. (2015). The radiation stability of glycine in solid CO2 – In situ laboratory measurements with applications to Mars. Icarus, 252, 466–472. doi:10.1016/j.icarus.2015.02.008
  • Gibb, E. L., Bonev, B. P., DiSanti, M. A., Villanueva, G. L., Paganini, L., & Mumma, M. J. (2016). An infrared search for HDO in Comet D/2012 S1 (ISON) and implications for iSHELL. The Astrophysical Journal, 816(2), 101. doi:10.3847/0004-637x/816/2/101
  • Gicquel, A., Milam, S. N., Coulson, I. M., Villanueva, G. L., Cordiner, M. A., Charnley, S. B., … Szutowicz, S. (2015). The evolution of volatile production in Comet C/2009 P1 (Garradd) during its 2011-2012 apparition. The Astrophysical Journal, 807(1), 19. doi:10.1088/0004-637x/807/1/19
  • Gudipati, M. S., Abou Mrad, N., Blum, J., Charnley, S. B., Chiavassa, T., Cordiner, M. A., … Yang, R. (2015). Laboratory studies towards understanding Comets. Space Sci Rev, 197(1-4), 101–150. doi:10.1007/s11214-015-0192-5
  • Haynes, K., Mandell, A. M., Madhusudhan, N., Deming, D., & Knutson, H. (2015). Spectroscopic evidence for a temperature inversion in the dayside atmosphere of hot-Jupiter WASP-33b. The Astrophysical Journal, 806(2), 146. doi:10.1088/0004-637x/806/2/146
  • Hudson, R. L., Gerakines, P. A., & Loeffler, M. J. (2015). Activation of weak IR fundamentals of two species of astrochemical interest in the Td Point Group – the importance of amorphous ices. Phys. Chem. Chem. Phys., 17(19), 12545–12552. doi:10.1039/c5cp00975h
  • Jang-Condell, H., Chen, C. H., Mittal, T., Manoj, P., Watson, D., Lisse, C. M., … Kuchner, M. (2015). Spitzer IRS spectra of Debris Disks in the Scorpius-Centaurus OB Association. The Astrophysical Journal, 808(2), 167. doi:10.1088/0004-637x/808/2/167
  • Khayat, A. S., Villanueva, G. L., Mumma, M. J., & Tokunaga, A. T. (2015). A search for SO2, H2S and SO above Tharsis and Syrtis volcanic districts on Mars using ground-based high-resolution sub-millimeter spectroscopy. Icarus, 253, 130–141. doi:10.1016/j.icarus.2015.02.028
  • Loeffler, M. J., & Hudson, R. L. (2015). Descent without modification? The thermal chemistry of H2O2 on Europa and other Icy Worlds. Astrobiology, 15(6), 453–461. doi:10.1089/ast.2014.1195
  • Mamajanov, I., Callahan, M. P., Dworkin, J. P., & Cody, G. D. (2015). Prebiotic alternatives to proteins: Structure and Function of hyperbranched polyesters. Orig Life Evol Biosph, 45(1-2), 123–137. doi:10.1007/s11084-015-9430-9
  • McKay, A. J., Cochran, A. L., DiSanti, M. A., Villanueva, G., Russo, N. D., Vervack, R. J., … Chanover, N. J. (2015). Evolution of H2O, CO, and CO2 production in Comet C/2009 P1 Garradd during the 2011–2012 apparition. Icarus, 250, 504–515. doi:10.1016/j.icarus.2014.12.023
  • Nesvold, E. R., & Kuchner, M. J. (2015). A SMACK model of colliding planetesimals in the β Pictoris debris disk. The Astrophysical Journal, 815(1), 61. doi:10.1088/0004-637x/815/1/61
  • Paganini, L., Mumma, M. J., Villanueva, G. L., DiSanti, M. A., & Bonev, B. P. (2015). The volatile composition of Comet C/2003 K4 (LINEAR) at near-IR wavelengths – Comparisons with results from the Nançay radio telescope and from the ODIN, Spitzer, and SOHO space observatories. The Astrophysical Journal, 808(1), 1. doi:10.1088/0004-637x/808/1/1
  • Smith, K. E., Gerakines, P. A., & Callahan, M. P. (2015). Metabolic precursors in astrophysical ice analogs: implications for meteorites and comets. Chem. Commun., 51(59), 11787–11790. doi:10.1039/c5cc03272e
  • Stark, C. C., Roberge, A., Mandell, A., Clampin, M., Domagal-Goldman, S. D., McElwain, M. W., & Stapelfeldt, K. R. (2015). Lower limits on aperture size for an ExoEarth-detecting coronagraphic mission. The Astrophysical Journal, 808(2), 149. doi:10.1088/0004-637x/808/2/149
  • Taquet, V., López-Sepulcre, A., Ceccarelli, C., Neri, R., Kahane, C., & Charnley, S. B. (2015). Constraining the abundances of complex organics in the inner regions of Solar-type Protostars. The Astrophysical Journal, 804(2), 81. doi:10.1088/0004-637x/804/2/81
  • Vandaele, A. C., Neefs, E., Drummond, R., Thomas, I. R., Daerden, F., Lopez-Moreno, J-J., … Wolff, M. (2015). Science objectives and performances of NOMAD, a spectrometer suite for the ExoMars TGO mission. Planetary and Space Science, 119, 233–249. doi:10.1016/j.pss.2015.10.003
  • Villanueva, G. L., Altieri, F., Clancy, R. T., Encrenaz, T., Fouchet, T., Hartogh, P., Lellouch, E., Lopéz-Valverde, M. A., Mumma, M. J., Novak, R. E., Smith, M. D., Vandaele, A-C., Wolff, M. J., Ferruit, P., & Milam, S. N. (2016). Unique spectroscopy and imaging of Mars with the James Webb Space Telescope. Astronomical Society of the Pacific, Volume 128, Number 959
  • Villanueva, G. L., Mumma, M. J., Novak, R. E., Kaufl, H. U., Hartogh, P., Encrenaz, T., … Smith, M. D. (2015). Strong water isotopic anomalies in the martian atmosphere: Probing current and ancient reservoirs. Science, 348(6231), 218–221. doi:10.1126/science.aaa3630
  • Willacy, K., Alexander, C., Ali-Dib, M., Ceccarelli, C., Charnley, S. B., Doronin, M., … Zicler, E. (2015). The composition of the Protosolar Disk and the formation conditions for Comets. Space Sci Rev, 197(1-4), 151–190. doi:10.1007/s11214-015-0167-6
  • Wirström, E. S., Adande, G. R., Milam, S. N. Charnley, S. B., Cordiner, M.A. (2015). 15N fractionation in star-forming regions and Solar System objects. Astronomy in Focus, in press

2015 Teams