Diapositiva 1 - IDEALS

Diapositiva 1 - IDEALS

Stability of extraterrestrial glycine under energetic particle radiation estimated from 2 keV electron bombardment experiments. Beln Mat, Isabel Tanarro, Rafael Escribano, Miguel A. Moreno Vctor J. Herrero Instituto de Estructura de la Materia IEM-CSIC, Madrid INSTITUTO DE ESTRUCTURA [email protected] DE LA MATERIA ISMS - 70TH MEETING - JUNE 22-26, 2015 - CHAMPAIGN-URBANA, ILLINOIS glycine Detected in our Solar System Comets Meteorites The Deep Impact probe Image: NASA/JPLCaltech/UMD Murchinson meteorite: 20 aminoacids detected glycine the most abundant Not detected in the Interstellar Medium However other organic molecules of similar complexity have been found

NH2-CH2-COOH HCOOCH3 HOCH2CH2OH CH3CHO glycine In the laboratory Synthesized by UV irradiation of ice analogues containing H2O, NH3, CO2, CO, CnH2n+2 It can be formed in the conditions available in interstellar ice mantles Could glycine have been delivered to planets by meteorites and comets, and thus be the seed of life? Could glycine resist the radiation field in space? Laboratory studies indicate that glycine would be destroyed by UV irradiation in the diffuse ISM and in unshielded surfaces within the Solar System In dense molecular clouds or in the subsurface of Solar System bodies the external photon flux decreases rapidly, but glycine can still be destroyed by cosmic rays We are going to use 2 keV electrons to simulate the effect of cosmic rays on extraterrestrial glycine EXPERIMENTAL SETUP High vacuum chamber: 10-8 mbar Closed cycle He cryostat. 14 - 300K

Vertex 70 Bruker FTIR spectrometer. Normal incidence transmission. Sublimation mini-oven Electron gun Schematic view of the chamber glycine oven electron gun 2 keV electron flux : 8 1011 cm-2 s-1 a b s o rb a n c e Infrared spectra of vapor deposited glycine crystal 0.6 crystalline 300 K 300 K 0.4 0.2 zwiterionic -

neutral amorphous-zw 20 K 90 K 0.2 0.0 a b s o rb a n c e + a b s o rb a n c e 0.0 amorphous-(zw+ne) 20 K 20 K 0.08 0.04 0.00 3500 3000 2500

2000 1500 -1 wavenumber cm 1000 absorbance 0.04 (a) 300 K 15 min 41 min 0 min 6 min absorbance 90 5 nm layers 0.02 b -glycine at 300K 0.00 0.04 (b) 90 K 54 min 82 min 0 min

20 min 0.02 amorphous glycine at 40 K 0.00 (c) 40 K absorbance GLYCINE PROCESING by 2 keV electrons 0.04 42 min 72 min 117 min 0 min 20 min 0.02 amorphous glycine at 90 K 0.00 2400 2200 2000 1800 1600 1400 1200 1000 800 -1 wavenumber (cm ) Normalized intensity decay of the 1405 cm-1 band of glycine, in logarithmic scale, as a function of fluence We assumed a single forward first order reaction.

0.0 90 K, 90 nm 90 K, 35 nm 40 K, 80 nm 20 K, 84 nm -0.5 -1.0 ln(I / I0) -1.5 ln -2.0 -2.5 -3.0 -3.5 50 100 150 200 250 2 F(electrons/cm ) F = Fluence = Flux (electrons cm-2 s-1 ) time (s)

B. Mat et al., 2015, ApJ 806:151 ( ) s: destruction cross section (cm2) 300 K, 90 nm 0 I = F I0 300 T(K) s (10-16 cm2) 300 17.6 1 90 9.1 1 Comparison with Gerakines et al., Icarus (2012) Amorphous glycine processed with 0.8 MeV protons 900 nm H+ 0.8 MeV e- 2 keV

secondary electrons 90 nm Linear energy transfer (H+) 44.8 keV/mm Linear energy transfer (e-) 22 keV/mm Radiolisis yield G (molec/100eV) protons 14 K keV e- and MeV H+ produce similar effects when the irradiation reaches the whole sample 5.8 0.5 electrons 20K 5.6 0.6 irradiation with e- appropriate to simulate cosmic rays half-life dose D1/2 the energy required to reduce the initial concentration to 50% Location Dense ISM

T (K) 10 Radiation dose rate Glycine Half-life (eV/molec/year) (year) 1.6 x 10-7 1.6 x 107 In dense ISM the amino acid could have a chance to survive until the protostellar phase and then be incorporated to the material of the resulting protoplanetary disk. Irradiation products at low temperature absorbance 0.06 (a) 0.03 0.00 90 K 40 K 40 K 2400

2200 2000 1800 1600 1400 1200 -1 wavenumber (cm ) absorbance 0.02 experimental 5 Gaussians sum (b) carrier Band center, cm-1 CO2 2340 OCN- 2164

CO 2136 CN- 2077 Amide I 1673.3 Amide II 1573.4 Deform., scissor -CH3, -CH2 1480.9 Stretching, -RCO2- 1405.2 Amide III 1319.0 90 K 0.01 0.00 1800 1600

1400 -1 wavenumber (cm ) 1200 The tentative assignment of amide bands suggests that the irradiation process leads to the formation of polypeptides. summary and conclusions The effect of 2 keV electron irradiation is confirmed to be similar to that of MeV protons for samples with thickness below the penetration depth of the electrons. With the lifetimes estimated in the present work there is a slim chance, that hypothetical interstellar glycine might have survived the passage from the pre-solar dense molecular cloud to the present Solar System. INSTITUTO DE ESTRUCTURA DE LA MATERIA

Recently Viewed Presentations

  • Conditional Processing - Rowan University

    Conditional Processing - Rowan University

    Lecture 6 Conditional Processing Assembly Language for Intel-Based Computers, 4th edition Kip R. Irvine Outline Boolean and Comparison Instructions Conditional Jumps Conditional Loops High-Level Logic Structures Logic Instructions Syntax for AND, OR, XOR, and TEST: op-code destination, source AND, OR...
  • A Line-Storm Song

    A Line-Storm Song

    Analysis This poem symbolizes the meaning of how the rain and the wind is heard with a higher force than a voice of a human (Line 9). Rhyme Scheme- (abab cdcd efef) the way this poem is written could be...
  • Gettysburg Cemetery Dedication - Peter Norvig

    Gettysburg Cemetery Dedication - Peter Norvig

    Abraham Lincoln Agenda Met on battlefield (great) Dedicate portion of field - fitting! Unfinished work (great tasks) Not on Agenda! Dedicate Consecrate Hallow (in narrow sense) Add or detract Note or remember what we say Review of Key Objectives &...
  • You are traveling to PT-FI in Indonesia for

    You are traveling to PT-FI in Indonesia for

    Planning your travel to Indonesia. The . FM Travel Center. will assist with the coordination of all aspects of your travel to Indonesia, including local transportation and lodging. Following are the consultants who are available to assist in various areas:...
  • Main Presentation Title

    Main Presentation Title

    Define goals. An entity should determine why it is quantifying FLW in order to determine what to quantify and how to undertake the quantification. Goals may relate to food security, economic performance, environmental impact, or some combination of the three....
  • Electricity


    Measuring Electrical Energy. You can save energy by using appliances with lower power ratings. The unit for energy is still the Joule (J) Often the power company will use Kilowatt-hour (kW-h) to measure the energy used. This makes sense, it...
  • Lecture Presentation Chapter 3 Matter and Energy John

    Lecture Presentation Chapter 3 Matter and Energy John

    Kinetic-Molecular Theory. The Kinetic-Molecular theory can be used to explain the states of matter in terms of the motions and energy of particles. ... When a symbol has two letters, the first is capitalized, and the second is lowercase. Other...
  • Michael S. Shur (VP, publications) CII 9017, RPI, 110 8th ...

    Michael S. Shur (VP, publications) CII 9017, RPI, 110 8th ...

    Sensor Council Publications Michael S. Shur (VP, publications) CII 9017, RPI, 110 8th street, Troy, NY 12180, USA (518) 276 2201; (518) 276 2990 (fax) [email protected]