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Theoretical Electron Affinities of Pahs and Electronic Absorption Spectra Of
A&A 432, 585–594 (2005) Astronomy DOI: 10.1051/0004-6361:20042246 & c ESO 2005 Astrophysics Theoretical electron affinities of PAHs and electronic absorption spectra of their mono-anions G. Malloci1,2,G.Mulas1, G. Cappellini2,3, V. Fiorentini2,3, and I. Porceddu1 1 INAF - Osservatorio Astronomico di Cagliari – Astrochemistry Group, Strada n. 54, Loc. Poggio dei Pini, 09012 Capoterra (CA), Italy e-mail: [gmalloci;gmulas;iporcedd]@ca.astro.it 2 Dipartimento di Fisica, Università degli Studi di Cagliari, Complesso Universitario di Monserrato, S. P. Monserrato-Sestu Km 0,700, 09042 Monserrato (CA), Italy e-mail: [giancarlo.cappellini;vincenzo.fiorentini]@dsf.unica.it 3 INFM - Sardinian Laboratory for Computational Materials Science (SLACS) Received 25 October 2004 / Accepted 8 November 2004 Abstract. We present theoretical electron affinities, calculated as total energy differences, for a large sample of polycyclic aromatic hydrocarbons (PAHs), ranging in size from azulene (C10H8) to dicoronylene (C48H20). For 20 out of 22 molecules under study we obtained electron affinity values in the range 0.4–2.0 eV, showing them to be able to accept an additional electron in their LUMO π orbital. For the mono-anions we computed the absolute photo-absorption cross-sections up to the vacuum ultraviolet (VUV) using an implementation in real time and real space of the Time-Dependent Density Functional Theory (TD–DFT), an approach which has already been proven to yield accurate results for neutral and cationic PAHs. Comparison with available experimental data hints that this is the case for mono-anions as well. We find that PAH anions, like their parent molecules and the corresponding cations, display strong π∗ ← π electronic transitions in the UV. -
Contamination Control Technology Study for Achieving the Science Objectives of Life-Detection Missions
Contamination Control Technology Study for Achieving the Science Objectives of Life-Detection Missions Study Team: Chris McKay, NASA ARC, (650)604-6864, [email protected] (submitting author) Alfonso Davila, NASA ARC, [email protected] Jennifer Eigenbrode, NASA GSFC, [email protected] Chris Lorentson, NASA GSFC, [email protected] Rob Gold, JHU/APL, [email protected] John Canham, Northrop Grumman/NASA GSFC, [email protected] Anthony Dazzo, KBR Inc./NASA GSFC, [email protected] Therese Errigo, NASA GSFC, [email protected] Faith Kujawa, JHU/APL, [email protected] Dave Kusnierkiewicz, JHU/APL, [email protected] Charles Sandy, ILC Dover, crsandy @ilcdover.com Erich Schulze, JHU/APL, Erich.Schulze@jhuapl Antonios Seas, NASA GSFC [email protected] Science Contamination Control Technology Study Summary: This white paper summaries technological advances in science-required contamination-control engineering for in situ and sample-return life-detection missions in the Solar System. Key study results are: 1) New spacecraft !arrier design that accommodates MMRT$s% is cleana!le% and is repaira!le. &) 'urge gas cleanliness of 1 part per trillion HC impurity limit is feasible. )) The !arrier reduces particle contamination *likely !iological) from fairing to spacecraft !y 1, -&-1,-). -) Spacecraft surfaces protected !y !arrier are 1,-&,. cleaner after launch than !efore launch. /) 0n-1ight !a+e-out of critical surfaces significantly reduced molecular contamination *!y 1,-3 to 1,-1&). 0mplementing a full spacecraft !arrier% collector cover and purge% and in-1ight cleaning steps will achieve cleanliness levels required of science instruments *down to femtomolar levels of !iomolecules). -
Photo-Processing of Astro-Pahs
Photo-processing of astro-PAHs C Joblin1, G Wenzel1, S Rodriguez Castillo1,2, A Simon2,H Sabbah1,3, A Bonnamy1, D Toublanc1, G Mulas1,4, M Ji1, A Giuliani5,6, L Nahon5 1Institut de Recherche en Astrophysique et Plan´etologie(IRAP), Universit´ede Toulouse (UPS), CNRS, CNES, 9 Avenue du Colonel Roche, F-31028 Toulouse Cedex 4, France 2Laboratoire de Chimie et Physique Quantiques (LCPQ/IRSAMC), Universit´ede Toulouse and CNRS,UT3-Paul Sabatier, 118 Route de Narbonne, 31062 Toulouse, France 3Laboratoire Collisions Agr´egatsR´eactivit´e(LCAR/IRSAMC), Universit´ede Toulouse (UPS), CNRS, 118 Route de Narbonne, F-31062 Toulouse, France 4Istituto Nazionale di Astrofisica (INAF), Osservatorio Astronomico di Cagliari, Via della Scienza 5, I-09047 Selargius (Cagliari), Italy 5Synchrotron SOLEIL, L'Orme des Merisiers, F-91192 Gif-sur-Yvette Cedex, France 6INRA, UAR1008, Caract´erisationet Elaboration des Produits Issus de l'Agriculture, F-44316 Nantes, France E-mail: [email protected] Abstract. Polycyclic aromatic hydrocarbons (PAHs) are key species in astrophysical environments in which vacuum ultraviolet (VUV) photons are present, such as star-forming regions. The interaction with these VUV photons governs the physical and chemical evolution of PAHs. Models show that only large species can survive. However, the actual molecular properties of large PAHs are poorly characterized and the ones included in models are only an extrapolation of the properties of small and medium-sized species. We discuss here experiments performed on trapped ions including some at the SOLEIL VUV beam line DESIRS. We focus + on the case of the large dicoronylene cation, C48H20, and compare its behavior under VUV processing with that of smaller species. -
Introduction to Astronomy from Darkness to Blazing Glory
Introduction to Astronomy From Darkness to Blazing Glory Published by JAS Educational Publications Copyright Pending 2010 JAS Educational Publications All rights reserved. Including the right of reproduction in whole or in part in any form. Second Edition Author: Jeffrey Wright Scott Photographs and Diagrams: Credit NASA, Jet Propulsion Laboratory, USGS, NOAA, Aames Research Center JAS Educational Publications 2601 Oakdale Road, H2 P.O. Box 197 Modesto California 95355 1-888-586-6252 Website: http://.Introastro.com Printing by Minuteman Press, Berkley, California ISBN 978-0-9827200-0-4 1 Introduction to Astronomy From Darkness to Blazing Glory The moon Titan is in the forefront with the moon Tethys behind it. These are two of many of Saturn’s moons Credit: Cassini Imaging Team, ISS, JPL, ESA, NASA 2 Introduction to Astronomy Contents in Brief Chapter 1: Astronomy Basics: Pages 1 – 6 Workbook Pages 1 - 2 Chapter 2: Time: Pages 7 - 10 Workbook Pages 3 - 4 Chapter 3: Solar System Overview: Pages 11 - 14 Workbook Pages 5 - 8 Chapter 4: Our Sun: Pages 15 - 20 Workbook Pages 9 - 16 Chapter 5: The Terrestrial Planets: Page 21 - 39 Workbook Pages 17 - 36 Mercury: Pages 22 - 23 Venus: Pages 24 - 25 Earth: Pages 25 - 34 Mars: Pages 34 - 39 Chapter 6: Outer, Dwarf and Exoplanets Pages: 41-54 Workbook Pages 37 - 48 Jupiter: Pages 41 - 42 Saturn: Pages 42 - 44 Uranus: Pages 44 - 45 Neptune: Pages 45 - 46 Dwarf Planets, Plutoids and Exoplanets: Pages 47 -54 3 Chapter 7: The Moons: Pages: 55 - 66 Workbook Pages 49 - 56 Chapter 8: Rocks and Ice: -
Arxiv:2005.14671V2 [Astro-Ph.EP] 30 Jun 2020 Tion Et Al
Draft version July 1, 2020 Typeset using LATEX twocolumn style in AASTeX62 The Gaia-Kepler Stellar Properties Catalog. II. Planet Radius Demographics as a Function of Stellar Mass and Age Travis A. Berger,1 Daniel Huber,1 Eric Gaidos,2 Jennifer L. van Saders,1 and Lauren M. Weiss1 1Institute for Astronomy, University of Hawai`i, 2680 Woodlawn Drive, Honolulu, HI 96822, USA 2Department of Earth Sciences, University of Hawai`i at M¯anoa, Honolulu, HI 96822, USA ABSTRACT Studies of exoplanet demographics require large samples and precise constraints on exoplanet host stars. Using the homogeneous Kepler stellar properties derived using Gaia Data Release 2 by Berger et al.(2020), we re-compute Kepler planet radii and incident fluxes and investigate their distributions with stellar mass and age. We measure the stellar mass dependence of the planet radius valley to +0:21 be d log Rp/d log M? = 0:26−0:16, consistent with the slope predicted by a planet mass dependence on stellar mass (0.24{0.35) and core-powered mass-loss (0.33). We also find first evidence of a stellar age dependence of the planet populations straddling the radius valley. Specifically, we determine that the fraction of super-Earths (1{1.8 R⊕) to sub-Neptunes (1.8{3.5 R⊕) increases from 0.61 ± 0.09 at young ages (< 1 Gyr) to 1.00 ± 0.10 at old ages (> 1 Gyr), consistent with the prediction by core-powered mass- loss that the mechanism shaping the radius valley operates over Gyr timescales. Additionally, we find a tentative decrease in the radii of relatively cool (Fp < 150 F⊕) sub-Neptunes over Gyr timescales, which suggests that these planets may possess H/He envelopes instead of higher mean molecular weight atmospheres. -
Periodic Habitability in Northern Plains Ground Ice: the Icebreaker Life Mission Plan
Astrobiology Science Conference 2017 (LPI Contrib. No. 1965) 3478.pdf PERIODIC HABITABILITY IN NORTHERN PLAINS GROUND ICE: THE ICEBREAKER LIFE MISSION PLAN. C. Stoker1, C. McKay1, A. Davila1 , B. Glass2, V. Parro3, 1 Space Science Division, NASA Ames Research Center, Moffett Field CA, 2Exploration Technology Division, NASA Ames Research Center, Moffett Field CA, 3Centro de Astrobiología (INTA-CSIC), Madrid, Spain Introduction:The results from the 2008 Phoenix and future proposals are planned. The mission returns mission that sampled ground ice at 68oN latitude, along to the well-characterized Phoenix landing site with a with climate modeling studies, indicate that the high N. payload designed to address the following science latitude ice-rich regolith at low elevations is likely to goals: (1) search for biomolecular evidence of life; (2) be a recently habitable place on Mars [1]. search for organic matter from either exogeneous or Habitable Conditions Evidence: Ice was found endogeneous sources using methods that are not within 3-5 cm of the surface. If warmer conditions spoiled by the presence of perchlorate; (3) characterize occur, the ice could provide a source of liquid water. oxidative species that produced reactivity of soils seen Phoenix found evidence for liquid water processes by Viking; and 4) assess the habitability of the ice including 1) beneath 3 -5 cm of dry soil, segregated bearing soils. The Icebreaker Life payload hosts a 1-m pure ice was discovered in patches covering 10% of drill that brings cuttings samples to the surface where the area explored, 2) calcite mineral was detected in they are delivered to three instruments. -
L115 Modeling the Unidentified Infrared Emission With
The Astrophysical Journal, 511:L115±L119, 1999 February 1 q 1999. The American Astronomical Society. All rights reserved. Printed in U.S.A. MODELING THE UNIDENTIFIED INFRARED EMISSION WITH COMBINATIONS OF POLYCYCLIC AROMATIC HYDROCARBONS L. J. Allamandola, D. M. Hudgins, and S. A. Sandford NASA Ames Research Center, MS 245-6, Moffett Field, CA 94035 Received 1998 July 13; accepted 1998 November 24; published 1999 January 18 ABSTRACT The infrared emission band spectrum associated with many different interstellar objects can be modeled successfully by using combined laboratory spectra of neutral and positively charged polycyclic aromatic hydro- carbons (PAHs). These model spectra, shown here for the ®rst time, alleviate the principal spectroscopic criticisms previously leveled at the PAH hypothesis and demonstrate that mixtures of free molecular PAHs can indeed account for the overall appearance of the widespread interstellar infrared emission spectrum. Furthermore, these models give us insight into the structures, stabilities, abundances, and ionization balance of the interstellar PAH population. These, in turn, re¯ect conditions in the emission zones and shed light on the microscopic processes involved in the carbon nucleation, growth, and evolution in circumstellar shells and the interstellar medium. Subject headings: infrared: ISM: lines and bands Ð ISM: individual (Orion Bar, IRAS 2227215435) Ð line: formation Ð line: identi®cation Ð line: pro®les Ð molecular data Ð radiation mechanisms: nonthermal 1. INTRODUCTION resemblance of the -
Coronene Encapsulation in Singlewalled Carbon Nanotubes
CHEMPHYSCHEM ARTICLES DOI: 10.1002/cphc.201301200 Coronene Encapsulation in Single-Walled Carbon Nanotubes: Stacked Columns, Peapods, and Nanoribbons Ilya V. Anoshkin,*[a] Alexandr V. Talyzin,*[b] Albert G. Nasibulin,[a, e] Arkady V. Krasheninnikov,[c] Hua Jiang,[a] Risto M. Nieminen,[d] and Esko I. Kauppinen[a] Encapsulation of coronene inside single-walled carbon nano- tions between the coronene molecules and the formation of tubes (SWNTs) was studied under various conditions. Under hydrogen-terminated graphene nanoribbons. It was also ob- high vacuum, two main types of molecular encapsulation were served that the morphology of the encapsulated products observed by using transmission electron microscopy: coronene depend on the diameter of the SWNTs. The experimental re- dimers and molecular stacking columns perpendicular or tilted sults are explained by using density functional theory calcula- (45–608) with regard to the axis of the SWNTs. A relatively tions through the energies of the coronene molecules inside small number of short nanoribbons or polymerized coronene the SWNTs, which depend on the orientation of the molecules molecular chains were observed. However, experiments per- and the diameter of the tubes. formed under an argon atmosphere (0.17 MPa) revealed reac- 1. Introduction Graphene nanoribbons (GNRs) are of great interest for various in SWNTs by using thermally induced fusion of the molecular applications due to their unique electronic properties.[1–7] GNRs precursors: coronene and perylene.[17] The nanoribbons exhib- -
Carbon Monoxide As a Metabolic Energy Source for Extremely Halophilic Microbes: Implications for Microbial Activity in Mars Regolith
Carbon monoxide as a metabolic energy source for extremely halophilic microbes: Implications for microbial activity in Mars regolith Gary M. King1 Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803 Edited by David M. Karl, University of Hawaii, Honolulu, HI, and approved March 5, 2015 (received for review December 31, 2014) Carbon monoxide occurs at relatively high concentrations (≥800 that low organic matter levels might indeed occur in some deposits parts per million) in Mars’ atmosphere, where it represents a poten- (e.g., 12). Even so, it is uncertain whether this material exists in a tially significant energy source that could fuel metabolism by a local- form or concentrations suitable for microbial use. ized putative surface or near-surface microbiota. However, the The Martian atmosphere has largely been ignored as a potential plausibility of CO oxidation under conditions relevant for Mars in energy source, because it is dominated by CO2 (24, 25). Ironically, its past or at present has not been evaluated. Results from diverse UV photolysis of CO2 forms carbon monoxide (CO), a potential terrestrial brines and saline soils provide the first documentation, to bacterial substrate that occurs at relatively high concentrations: our knowledge, of active CO uptake at water potentials (−41 MPa to about 800 ppm on average, with significantly higher levels for −117 MPa) that might occur in putative brines at recurrent slope some sites and times (26, 27). In addition, molecular oxygen lineae (RSL) on Mars. Results from two extremely halophilic iso- (O2), which can serve as a biological CO oxidant, occurs at lates complement the field observations. -
Robotics and Automation for “Icebreaker” B.J
ROBOTICS AND AUTOMATION FOR “ICEBREAKER” B.J. Glass (1), G. Paulsen(2), A. Dave (1), C. McKay(1) (1) NASA Ames Research Center, Moffett Field, CA 94035 USA; Email: [email protected] (2) Honeybee Robotics, Pasadena, CA 91103 USA; Email: [email protected] ABSTRACT components that will penetrate below the ground, and place these inside a biobarrier. To prevent The proposed “Icebreaker” mission is a return to spores from traveling onto the drill auger/bit via the Mars polar latitudes first visited by the Phoenix sample transfer, there must be an air gap between mission in 2007-08. Exploring and interrogating the sterilized drill and a less-sterilized robotic the shallow subsurface of Mars from the surface sample delivery subsystem that could contact the will require some form of excavation and “dirty” spacecraft instruments (which will not be penetration, with drilling being the most mature heat sterilized to Viking standards). approach. A series of 0.5-5m automated rotary and rotary-percussive drills developed over the past Since 2006, NASA has developed a Discovery- decade by NASA Ames and Honeybee Robotics class mission concept, called "Icebreaker" (Fig. 1), provide a capability that could fly on a Mars which is a Lockheed-Martin (Phoenix-derived) surface mission within the next decade. Surface Mars polar lander with life and organics detection robotics have been integrated for sample transfer to instruments and a 1m sampling drill [4]. The deck instruments, and the Icebreaker sample Icebreaker science payload has since 2010 also acquisition system has been tested successfully in been the baseline science payload for developing a Mars chambers and analog field sites to depths joint NASA-commercial Mars astrobiology between 1-3m. -
Monday 11Th May 2020 L.O. I Can Read and Give an Assessment of a Story
Monday 11th May 2020 L.O. I can read and give an assessment of a story THE HERO’S JOURNEY is a template (a bit like a story mountain) that has been used for some of the greatest stories ever told, all the way back from ancient myths to modern classics like Narnia and Star wars. Over the next three weeks, we are going to use it to write our own story One of the reasons STAR WARS is such a great movie is it because it follows the HERO’S JOURNEY model. Today, you are going to read / watch this version of the Hero’s journey and see how it fits into the format for our first act! The subtitles just refer to the stages of the story - don’t worry about them yet! Just read the story and if you have internet access look up / click on the clips on youtube. ORDINARY WORLD Luke Skywalker was a poor and humble boy who lived with his aunt and uncle in a scorching and desolate planet world called Tatooine. His job was to fix robots on the family farm and and he spent his free time flying planes through the rocky canyons. He loved his aunt and uncle but dreamed of a more exciting and adventurous life https://www.youtube.com/watch?v=8wJa1L1ZCqU Search for ‘Luke Skywalker binary sunset’ CALL TO ADVENTURE One day, Luke found a broken old R2 astromech droid. It was called R2-D2 and it was a mischievous, cheeky robot who made lots of bleeps and flashes. -
Phd Projects at the Institute of Origins
PhD projects at the Institute of Origins. A list of possible PhD projects at the Institute of Origins appear in the following pages. If you have any questions regarding any projects please contact the individual supervisors. Also if you have other suggestions for a project please contact us as well. The chemical composition of star forming regions near and far .................................... 3 ! Modelling the solubilities of organic solids in hydrocarbon liquids: application to the geology and astrobiology of Titan. .................................................................................... 4! Modeling turbulent flows in solar quiescent prominences ...............................................5! The zoo of exo-planets..................................................................................................8! Understanding the formation of heavy negative ions at Titan and Enceladus................9! Mapping anthropogenic versus natural sources of atmospheric CO2 ............................11! Probing Large Scale Structure with High Energy Neutrinos.........................................13! Future Moon Missions and High Energy Neutrinos ......................................................15! Measuring Cosmic Particles and the Upper Atmosphere with LOFAR.........................17! Mimicking planetary environments for assessing the survivability of bacterial organisms within an artificial environmental chamber. A combined planetary atmosphere and microbiological study for exploring panspermia................................