The Astrobiology Research Activity at INAF-Osservatorio Astronomico di Palermo

1. Angela Ciaravella The Astrobiology Research Activity at INAF-Osservatorio Astronomico di Palermo Astrobiology: interdisciplinary study of life in space, combining aspects of astronomy, biology and geology • Study the effects of X-ray radiation on biological molecules: • DNA free and clay adsorbed in water solution • Amino Acids in water solution • Since 2005 building the Laboratory for Experimental AstroBiology (LEAB) XACT

2. Experimental Astrobiology at OAPA Origin of Life Early X-ray and UV radiation Synthesis of the building blocks of life UV + X-ray irradiation of ice analogoues Life started on the Earth 3.8 – 4 × 109 yr Harsch radiation field Many uncertanties on the Earth atmosphere Effects of radiation on Organic molecules A new facility (LEAB) for a more realistic scenario DNA and Amino Acids Irradiation Experiments

3. Origin of Life in space on the Earth Organic molecules are in: ▪ Interstellar clouds ▪ Micrometeorites (0.01 – 0.1mm) today: 50- 100 tons/day ▪ Meteorites (+amino acids) Heavy bombardment by comets, meteorites and micrometeorites main carriers of organic material 4.2 - 3.9 × 109 yr ago = 103× today value Miller’s Experiment Hp: Earth Atmosphere (NH3, CH4, H2 + H2O vapor) + Spark discarge Res: many organic compounds including amino acids However: 1) H rich atmosphere quickly lost 2) N2, CO, CO2 and H2O inefficient for organic molecules Murchison Miller Glycine Alanine Valine Serine Proline ….. UV ? Many open questions: Experiment & Results Why just UV? Amino Acids high photo-distruction rate Protection mechanisms H2O, CO, CO2, CH3OH, NH3 (Muñoz-Caro et al.; Bernstein et al. Nat. 2002) The building blocks of life were built

4. X-ray Emission from Solar Type Stars:I Sun @ max Sun @ min Early X-ray Sun: more active, hard and bright …but today is a modest X-ray source (LX = 1027 – 1030 erg/sec) • X-ray emission fades much more rapidly than UV. • The variations depends on the hardness of radiation: the hardest the fastest (Micela 2002). • In the 1-10 keV range, X photons @ Earth were >103higher than today when the Sun was only 108 yr old.

5. X-ray Emission from Solar Type Stars: II Young Stars are Very Active in X-ray LX = 1031 – 1033 erg/sec • energetic radiation, very huge daily or weekly X-ray flares (Feigelson \& Montmerle 1999;Feigelson et al. 2003) • T Tauri showflares emitting at 8 keV for more than two day (Favata et al. 2005). • Very large flaring structures ( L » R* ) • not found in more evolved star • X-rays from the flare can heat up the planet-forming disk

6. X-ray Irradiation of DNA The Sun today (1.5 –12.4 keV) (erg sec-1 cm -2 ) Clay Ads. Free 10-5 minimum 8 months 3 × 10-3maximum 19 hours 10-1large flares 34 min (erg sec-1 cm -2 ) (keV) Al 1.49 0.15 Ti 4.51 0.17 Cu 8.04 0.20 Irradiation Dose : 102 - 5.8 × 104 erg ⃟⃟ ⃟Clay Adsorbed DNA is resistent ΔΔΔto the X-ray irradiation ***Free DNA is severely damaged by X-rays and the damage depends on the energy dose rather than the hardness of radiation (Ciaravella et al 2004,Int. J. Atrb.)

7. X-ray Irradiation of Amino Acids TryptophanC11H12N2O2 Preliminary Results • X-rays break the aliphatic chain: • Alanine • Alanine-Alanine peptide • UV (2780 Å) breaks the aromatic group • Solvent plays an important role (Ciaravella et al 2007, in prep)

8. The LEAB Facility: Why? UV IR Spectroscopy X-ray Mass Spectrometer Simulate space conditions : • A cold finger with T=10 -300 K ± 1 K • A more realistic scenario for the synthesis of amino acids: • Not only UV HI Lya (usually used) • X-ray source (< 20 keV) (no used so far) • more penetrating into protoplanetary disk and dust grains • Multi-wavelength source quiete & flaring emission • Big chamber (20 ×30 cm): • allowing for many simultaneous diagnostics and irradiation sources • High clean vacuum (~10-11 mbar) oil-free vacuum pumping systems • Mass spectrometer system up to 200 amu ~ 80 k€

9. ThePast, OngoingandFuture Experimental Plan X-ray irradiation of free & clay adsorbed DNA in water solution X-ray & UV irradiation of Amino Acids in icy mixtures Survival X-ray & UV irradiation of Amino Acids in water solution Spring-Summer 2008 Amino acids in icy mixture implanted into different substrates Clays can protect DNA from X-ray & UV radiation Protection ▪ Molecular complexity sustainable in space ▪ May radiation induce formation of more complex molecular structures Complexity End 2008-2009 1) Synthesis of amino acids 2) Synthesis of amino acids inside cavities Synthesis

10. Funds & Collaborations Sources of funds: • Local Obs. (Director) (main source! ~ 70 k€ ) • PRIN-INAF 2006 - 60k€ ( 50 k€ OAPA; ~20 k€ lab.) • ASI call“Nuove Tecnologie e Spin-in: selezione di idee”Nov. 2006 proposal(selected) • FP7_ITN (Initial Training Network)): COMIS:Complex Organic Molecules in Space : the first step toward understanding life in the Universe (selected)(1 Early Stage Researcher) • FEBO:Facility for Exo-Biology Observations (ASI submitted) • FP7_TNA (Trans National Activity) within Europlanet(in preparation) XACT + LEAB facilities Collaborations: • C. Cecchi-Pestellini (INAF-OACA) • N. La Barbera, S. Giarrusso (INAF-IASF) • Chemists: (F. Mingoia; A. Venezia - CNR/INSM) • Biologists:(A. Puglia, M. Franchi, E. Gallori;Univ. Palermo & Firenze) • European scientists (Muñoz-Caro, Horneck, ……..)