Nuva2020onlineworkshop Ora

e-Workshop 2020Welcome – October 27-29 Downloaded from the JCUVA server hosting the workshop The Ultraviolet Researcher for the Investigation of the Emergence of Life Gómez de Castro and the URIEL consortium FORMATION OF EARTH-LIKE PLANETS 30 AU • The inner most region of young planetary systems is only accessible via spectroscopic means. • This is the area were terrestrial planets do form. • The radiating plasmas as dusty thus polarimetry provide additional information on the composition and dynamics of the inner part of young planetary disks. UV Spectropolarimetry is the most sensitive tool to monitor and quantify the characteristics of the small dust particles carried by winds, and accretion streams. To detect the disturbances caused by nascent Earth-like planets. (from Gómez de Castro & Canet, 2021) POLARIZATION IS VARIABLE ON TIME SCALES OF DAYS • It is a complex area where many physical components share similar electron temperatures and radiating at UV wavelengths Magnetosphere • Polarization variability has been detected in 35% of the stars with more than 2 observations. • The spectral tracers are not always different and polarimetry enables discrimination trough the dust Inner disk wind H2, CO, inner disk column, dust size distribution and alignment. Stellar atmosphere Accretion shocks • Comets during early life of planetary systems will be accesible Distribution of CS matter in AK Sco Nadeau & Bastien, 1986 Gómez de Castro et al. 2013 Late heavy PROTEINOGENIC LABORATORY EXPERIMENTS SIMULATING Bombardment AMINOACIDS EARLY EARTH CONDITIONS SPACE ICE & COMETS (3.9 Gy) Oldest signs of life formed in the -stromatolites- Miller Parker Muñoz-Caro Chen Earth Formation experiments 1952 et al. 2011 et al 2002 et al. 2008 (3.7 Gy) (4.54 Gy) Glycine Alanine Aspartic acid Serine Valine Glutamic acid letters to nature Crust & Oceans Phenylalanine (4.5-4.3 Gy) Methionine COOH H N COOH Gly 2 H2N NH2 NH2 Isoleucine D -Ala L-Ala D -2-ABA COOH Leucine H N H2N COOH 2 L-2-ABA H N H2N 2 Cysteine Histidine L-Ala 9 10 11 12 D -Val + ß-Ala Lysine L-Val H D -Ala H2N N NH2 Asparagine D,L NH -Pro H2N 2 NH2 L-Asp Pyrrolysine DAH D -Asp D -Ser 67P/Churyumov–Gerasimenko Proline DAP N-EtGly COOH O L-Ser H N H2N NH2 2 Glutamine NH2 Sar Glycine detected Arginine (Altwegg et al. 2016) Threonine Selenocysteine 2.5 5.0 7.5 10.0 12.5 15.0 17.5 20.0 22.5 25.0 27.5 30.0 32.5 35.0 37.5 40.0 42.5 Tryptophan Muñoz-Caro et al 2012 Time (min) Tyrosine Figure 1 Gas chromatogram showing the amino acids and other compounds generated programmed for 3 min at 70 8C, 5 8C min21, and 17.5 min at 180 8C; detection of total ion under simulated interstellar pre-cometary conditions. Data were obtained from analysis of current with GC–MSD system Agilent 6890/5973). The inset shows the determination of the room temperature residue of photoprocessed interstellar medium ice analogue taken alanine enantiomers in the above sample (Chirasil-L-Val 25 m, single ion monitoring for after 6 M HCl hydrolysis and derivatization (ECEE derivatives, Varian-Chrompack Chirasil- Ala-ECEE base peak at 116 a.m.u.). DAP, diaminopentanoic acid; DAH, diaminohexanoic L-Val capillary column 12 m 0.25 mm inner diameter, layer thickness 0.12 mm; acid; a.m.u., atomic mass units. £ splitless injection, 1.5 ml min21 constant flow of He carrier gas; oven temperature this residue were saturated organic compounds containing car- groups showed relatively high abundances. Aspartic acid was the boxylic groups and hexamethylenetetramine16 –18. Previous work only dicarboxylic compound found in the residues. Decarboxyla- claimed the detection of trace amounts of a limited number of tion is known as the main photodamage of UV-exposed amino acids amino acids in photolysed interstellar ice analogues17,19. Except for and probably competes with photoproduction21. Decarboxylation glycine, however, these analytical results were not confirmed by should give rise to the formation of radicals that could react with isotopic labelling, a necessary verification to exclude contamination NH3 to favour the formation of diamino-compounds. with trace organic components. In the case of reported analyses of meteoritic material, the We analysed the residue by gas chromatography–mass spec- absolute abundances of the detected amino acids are enhanced by trometry (GC–MS) using a chiral capillary column. Using new, acid hydrolysis6. Similarly in our case, amino acids in the residue are more sensitive detection methods, we report here the identification detected at considerable amounts only after acid hydrolysis, which of 16 amino acids in the residue, 6 of which are protein constituents. probably indicates that these products are originally formed as Figure 1 shows the chromatogram corresponding to the residue peptidic molecules, and released as free amino acids after hydrolysis obtained from the photoprocessed interstellar ice analogue mixture. at room temperature. It has been suggested that hydrolysis of Most of the observed peaks were due to amino acids, but three hexamethylenetetramine, an abundant product of photolysis for exceptions were identified as 2,5-diaminopyrrole, 2,5-diamino- the selected ice mixture, leads to formation of amino acids18. In furan, and 1,2,3-triaminopropane. The calculated signal-to-noise order to test this possibility, an external standard of hexamethylene- ratio was S=N > 10, even for the least abundant amino acids tetramine was analysed using the same protocol as for the residues identified. A similar chromatogram was obtained for the isotopi- and no amino acids were detected. No evidence for contamination 13 13 cally labelled sample (molar concentration H2O: CH3OH:NH3: was found after comparison with the samples produced from C- 13 13 CO: CO2 2:1:1:1:1), with the exceptions of valine and proline, labelled reactants. We used the mass spectrometric data on amino- which were below¼ the detection limit. Proline was found in the 13C- acid ECEE (N-ethoxycarbonyl ethyl ester) derivatives reported in 22 labelled residue of a test sample, which did not contain CH3OH in the literature for identification. the starting ice composition, and therefore could not be a contami- The selected starting ice composition here reported is only nant. The abundance was obtained by integrating the peak area of a indicative, because the composition of the ice can vary significantly given amino acid calibrated with the corresponding standard. The for different sources. The NH3 ice abundance used was enhanced quantum yield (F) was obtained by dividing the abundance by the with respect to that derived from astronomical observations to number of photons. For the total amount of residue, F residue < obtain a larger amount of residue, but it is also based on the fact that 3 ð Þ 8:0 10ÿ (ref. 20). Glycine, the simplest amino acid, with NH3 photo-dissociates very readily, leading to other species, so that £ 5 F Gly < 3:6 10ÿ , was the most abundant. The total amino- the original budget of NH3 was probably larger than what is acidð quantumÞ £ yield was F < 1:0 10 4. Table 1 lists the detected observed. Additional irradiation experiments involving a ten £ ÿ molecules, and their corresponding abundances relative to glycine. times higher H2O ice concentration or deposition at 80 K, mon- The mass fragments of the elutants in the 12C and 13C samples are itored by infrared spectroscopy, showed that the residue production given along with their retention times (Rt). The main mass frag- was equally efficient, although the relative abundances of the main ments are shown in boldface in Table 1. For amino acids bearing components, hexamethylenetetramine and carboxylic acids, varied only one amino group, species with higher molecular mass were less somewhat23. abundant. We were surprised to find that species with two amino All the chiral amino acids detected showed enantiomeric separa- 404 © 2002 Macmillan Magazines Ltd NATURE|VOL 416|28 MARCH 2002|www.nature.com URIEL: THE PATH TO THE REMOTE DETECTION OF ALANINE UV Spectrum of comets Alanine’s circular dichroism spectrum Meierhenrichs et al. 2012 CO Cameron bands Spectra of comets obtained with the International Ultraviolet Explorer: Bradfield, Halley, Levy, Swift-Tuttle, Hyakutake The chirality of alanine, the enantiomeric imbalance detected in comets and meteorites (1%-60%), the polarization of the radiation from comets through scattering by the dust grains in the coma can make alanine detectable by remote sensing opening a new path to astrobiological research. Gómez de Castro & de Isidro-Gómez 2020 Circular polarized radiation Circular dichroism (CD) Optical Rotatory Dispersion (ORD) & )*+,, Linearly polarized radiation �",$ = �",$10 A ´? [�](�) = 2.1018×108 ∫ ∆� �< ��′, & =?)=@? Alanine abundance scaled from 67P/Churyumov–Gerasimenko’s glycine (graphs after Gómez de Castro & de Isidro-Gómez, 2020) URIEL Scientific Requirements and traceability matrix Scientific Scientific Measurements Main characteristics of URIEL Objectives Requirements High sensitivity spectro- Optical Ritchey-Chretien Mounting Search for signatures polarimetry in the 150-250 nm Rotation of the of alanine in comets spectral range. polarization vector layout Minimization of instrumental polarization Long slit. Mineralogy of Solar High sensitivity Primary size 50 cm diameter System and spectropolarimetry in the 150- Composition interstellar minor 600 nm spectral range bodies MgF2 Polarizer-Wollaston Prism Analyzer Variation of polarization Curved grating – dispersion 600 Measure the Instrument High sensitivity with wavelength. Wavelength

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