esa/estec 26-27 feb. 2007 effects of x-ray and uv radiation from very young sun on biomolecules...
TRANSCRIPT
ESA/ESTEC 26-27 Feb. 2007
Effects of X-ray and UV Radiation from Very Young Sun on Biomolecules
Angela CiaravellaINAF – Osservatorio Astronomico di Palermo
Network Activity JRA
Astrophysicists, Chemists, Physicists, Biologists…..
EUV and X-ray emission from Sun & starsModeling of planet atmosphere ……..Experimental EUV and X-ray
Conditions in the Early Solar System
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.
Heavy bombardment by: Comets, Meteorites and Micrometeorites
main carriers of organic material
4.2 - 3.9 × 109 yr ago = 1000 × today value
Solar Corona ( 1-2 × 106 K)
Yohkoh-SXT 3-40 Å band
Magnetic confined plasma in loops
….. seeds of life on the Earth
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
Flares and CMEs
Mass 1013 - 1016 g Speed >2700 km/sec (480km/sec) Energy 1032 ergRate 0.8 up to 6 day
Sometime
What about solar type stars?
Einstein, ….CHANDRA, XMM ….we learned a lot …..
Analysis of the flare decay
parameters of the flaring structure L, n, B
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
Sun
@ m
inSu
n @
max
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.
Young Stars are Very Active in X-ray
● energetic radiation, very huge daily or weekly X-ray flares (Feigelson \& Montmerle 1999;Feigelson et al. 2003)
● T Tauri show flares 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).
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 complexitymolecular 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.
The Experimental Plan
X-ray, UV, Vis 2 -104 eV (1- 7000 A).
32 m stainless-steel vacum beam lineclass 1000 clean_room (Barbera et al 1999).
The Laboratory Facilities
The Astrobiology Lab
The XACT Facility
High vacuum (10-10 mbar) Chamber Class 100 Clean room HI Lyα lampX-ray source (1.5 – 10 keV)Cryostat ( 10 K )Lasers, Detectors…
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
Estimate Time and Cost
The experimental plan is a 3 yr project
k€100
90
30
30