The Astrobiology Research Activity at INAF-Osservatorio Astronomico di Palermo
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Transcript of The Astrobiology Research Activity at INAF-Osservatorio Astronomico di Palermo
Angela Ciaravella
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)
Astrobiology: interdisciplinary study of life in space, combining aspects of astronomy, biology and geology
XACT
The Astrobiology Research Activity at INAF-Osservatorio Astronomico di Palermo
A. Ciaravella –The Astrobiology Research Activity – Palermo 19/12/2007
Experimental Astrobiology at OAPA
Effects of radiation on Organic molecules
Life started on the Earth 3.8 – 4 × 109 yr Harsch radiation field
Many uncertanties on the Earth atmosphere
Synthesis of the building blocks of life
UV + X-ray irradiation of ice analogoues
DNA and Amino AcidsIrradiation Experiments
Early X-ray and UV radiation
Origin of Life
A new facility (LEAB) for a more realistic scenario
A. Ciaravella –The Astrobiology Research Activity – Palermo 19/12/2007
Origin of LifeThe building blocks of life were built
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 lost2) N2, CO, CO2 and H2O inefficient for organic molecules
on the Earth
UV H2O, CO, CO2, CH3OH, NH3
GlycineAlanineValine Serine
Proline ….. (Muñoz-Caro et al.; Bernstein et al. Nat. 2002)
Murchison Miller
?Many open questions: Experiment & Results Why just UV?Amino Acids high photo-distruction rateProtection mechanisms
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
in space
A. Ciaravella –The Astrobiology Research Activity – Palermo 19/12/2007
Sun
@ m
inSu
n @
max
X-ray Emission from Solar Type Stars:I
● 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 higher than today when the Sun was only 108 yr old.
Early X-ray Sun: more active, hard and bright …but today is a modest X-ray source (LX = 1027 – 1030 erg/sec)
A. Ciaravella –The Astrobiology Research Activity – Palermo 19/12/2007
X-ray Emission from Solar Type Stars: II
● 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 day (Favata et al. 2005).
Young Stars are Very Active in X-ray
Very large flaring structures ( L » R* ) not found in more evolved star
X-rays from the flare can heat up the planet-forming disk
LX = 1031 – 1033 erg/sec
A. Ciaravella –The Astrobiology Research Activity – Palermo 19/12/2007
X-ray Irradiation of DNA
Free
Clay Ads.
Al 1.49 0.15 Ti 4.51 0.17 Cu 8.04 0.20
(erg sec-1 cm -2 )(keV )
Irradiation Dose : 102 - 5.8 × 104 erg
10-5 minimum 8 months 3 × 10-3 maximum 19 hours 10-1 large flares 34 min
The Sun today (1.5 –12.4 keV)(erg sec-1 cm -2 )
⃟ ⃟ ⃟ Clay Adsorbed DNA is resistent Δ Δ Δ to 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.)
A. Ciaravella –The Astrobiology Research Activity – Palermo 19/12/2007
X-ray Irradiation of Amino Acids
Tryptophan C11H12N2O2
ppm (t1)0.01.02.03.04.05.06.07.08.0
0
500
1000
1500
2000
1.00
1.03
1.00
1.00
1.01
3.07
-0.0
0
tri000 in D20
NH2
NH
COOH
HaHb1
Hb2
H2
H4H5
H6H7
ppm (t1)0.01.02.03.04.05.06.07.08.0
0
10
20
30
40
7.6167.5907.4207.3937.1797.1547.1297.0937.0677.043
4.962
3.9333.9173.9073.8913.4283.4113.3853.3693.3343.318
3.2533.2043.1773.1533.126
1.968
1.0951.0731.0571.036
0.0380.015
-0.051
tri 005 D2O "overdose of X"
H2NCHC
CH2
OHO
HN
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)
A. Ciaravella –The Astrobiology Research Activity – Palermo 19/12/2007
The LEAB Facility: Why? 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
IR Spectroscopy
UV
X-ray
Mas
s Sp
ectro
met
er
~ 80 k€
A. Ciaravella –The Astrobiology Research Activity – Palermo 19/12/2007
X-ray & UV irradiation of Amino Acids in water solution
X-ray irradiation of free & clay adsorbed DNA in water solution X-ray & UV irradiation of
Amino Acids in icy mixtures
Protection
Survival
Clays can protect DNA from X-ray & UV radiation
Complexity
Synthesis
Amino acids in icy mixture implanted into different substrates
▪ Molecular complexity sustainable in space▪ May radiation induce formation of more complex molecular structures
1) Synthesis of amino acids2) Synthesis of amino acids inside cavities
The Past, Ongoing and Future Experimental Plan
Spring-Summ
er 2008E
nd 2008-2009
A. Ciaravella –The Astrobiology Research Activity – Palermo 19/12/2007
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, ……..)
Funds & Collaborations