Effects of X-ray and UV Radiation from Very Young Sun on Biomolecules

1. Effects of X-ray and UV Radiation from Very Young Sun on Biomolecules Angela Ciaravella INAF – Osservatorio Astronomico di Palermo aciaravella@astropa.unipa.it Network Activity JRA Astrophysicists, Chemists, Physicists, Biologists….. EUV and X-ray emission from Sun & stars Modeling of planet atmosphere …….. Experimental EUV and X-ray ESA/ESTEC 26-27 Feb. 2007

2. Conditions in the Early Solar System Heavy bombardment by: Comets, Meteorites and Micrometeorites main carriers of organic material 4.2 - 3.9 × 109 yr ago = 1000 × today value Yohkoh-SXT 3-40 Å band Solar Corona ( 1-2 × 106 K) Magnetic confined plasma in loops ….. seeds of life on the Earth Very intense and hard radiation from the young Sun Energetic radiation from the early Sun is manly in term of EUV and X-ray emission and energetic particles.

3. Today X-ray Sun 10-4 10-5 10-6 10-7 10-8 3 × 1026 (0.1 keV) @ min < Lx >= 1027 erg/sec 5 × 1027 (0.2 keV) @ max

4. A flare • occurs when energy stored in magnetic fields is suddenly released • produces a burst of radiation from radio waves to X and Gamma rays Sometime Analysis of the flare decay parameters of the flaring structure L, n, B Mass 1013 - 1016 g Speed >2700 km/sec (480km/sec) Energy 1032 erg Rate 0.8 up to 6 day What about solar type stars? Einstein, ….CHANDRA, XMM ….we learned a lot ….. Flares and CMEs

5. Sun @ max Sun @ min Main Sequence Solar Type Stars 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 >103 times higher than today when the Sun was only 108 yr old.

6. 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 days large size of the flaring structures ( L » R* ) not found in more evolved stars • X-rays from the flare can heat up the planet-forming disk ………… LX = 1031 – 1033 erg/sec (Favata et al. 2005). Young Stars are Very Active in X-ray

7. The Experimental Plan Survival • Amino acids implanted in icy mixtures and irradiated with UV and X-ray quiescent & energetic transient Protection • Amino acids will be implanted in icy mixtures deposited onto different substrates assumed to be analogues of dust grain materials The role of mineral material of the dust aggregates in protecting both passively and actively the prebiotic chemicals will be studied. • Clays can protect DNA molecules from X-ray and UV radiation • (Ciaravella et al. 2004; Scappini et al., 2004) • Complexity • The survival of biological molecules can be function of their complexity • Irradiation of biological compounds of increasing complexity • molecular complexity sustainable in space • High energy irradiation may induce photo-degradation as well as an increase in molecular complexity. • Investigate whether and in which conditions the radiation may induce • formation of more complex molecular structures.

8. The Laboratory Facilities The XACT Facility X-ray, UV, Vis 2 -104 eV (1- 7000 A). 32 m stainless-steel vacum beam line class 1000 clean_room (Barbera et al 1999). The Astrobiology Lab • High vacuum (10-10 mbar) Chamber • Class 100 Clean room • HI Lyα lamp • X-ray source (1.5 – 10 keV) • Cryostat ( 10 K ) • Lasers, Detectors…

9. Estimate Time and Cost The experimental plan is a 3 yr project k€ 100 90 30 30 Upgrade of the X-ray source to simulate transient events (higher fluxes in the 1.5 -15 keV range) Contract personnel Supplies and running cost Travel