1. 2nd Brazilian COROT Workshop - Ubatuba, Nov 6 2005 WHY BEING EARTH-CENTERED WHEN SEARCHING FOR LIFE IN THE COSMIC NEIGHBORHOOD? 1 Divisão de Astrofísica, - INPE 2 Instituto de Biofísica Carlos Chagas Filho - UFRJ 3 Instituto Astronômico e Geofísico - IAG/USP 4 Instituto de Química - UFRJ 5 Observatório do Valongo - UFRJ Carlos Alexandre Wuensche 1 Claudia Lage 2 Amâncio Friaça 3 Sérgio Pilling 4 Heloísa Boechat-Roberty 5 Contato: alex@das.inpe.br

2. 2nd Brazilian COROT Workshop - Ubatuba, Nov 6 2005 A cosmological perspective to search of life in the Universe... Life building blocks come from these components... Ω b = 0.04 Ω T LET´S GIVE IT UP, THEN... Bennett et al., ApJ Suppl Series 2003 NOT!

3. 2nd Brazilian COROT Workshop - Ubatuba, Nov 6 2005 How can we define life? It is quite a subjective concept, but we can list some common characteristics ( J. Schneider, astro- ph/9604131, 1996; Szostak et al., Nature, 2001, Bains, Astrobiology 2005 ) –Complex and diversified interactions with the environment –System out of thermodynamical equilibrium –Memory + reading/recovering mechanism –Self-replication capability Life is a self-sustained chemical system, capable of evolution in a Darwinian sense (Joyce 1994).

4. 2nd Brazilian COROT Workshop - Ubatuba, Nov 6 2005 For a practical search, restrictive hipothesis... What kind of complex systems? –Liquid crystals, plasmas... Conservative hipothesis – a chemical system. –C, Si? Presence of a liquid millieu? –H 2 O: excelent solvant and abundant in the Universe Existence of a solid/liquid interface? –Favours molecular interactions... Questions 1) Does life need, necessarily, such atoms and physical-chemical conditions? 2) Can life develop, in another planet, under totally different conditions?

5. 2nd Brazilian COROT Workshop - Ubatuba, Nov 6 2005 Most definitions tend to be E ARTH-CENTERED So, let´s understand “Earth model”

6. 2nd Brazilian COROT Workshop - Ubatuba, Nov 6 2005

7. HABITABLE ZONE (68% e 95%) Lineweaver et al., Science, 303, 59 (2004)

8. 2nd Brazilian COROT Workshop - Ubatuba, Nov 6 2005 [X/H]=log(X/H)-log(X/H) Sun. Components: halo, thick and thin disks. Universe age: 13 Gyr. Solar age: 4.6 Gyr Minimum abundance to form terrestrial planets: [X/H]=-1.0 +/- 0.3. (Lineweaver, Icarus, 151, 307, 2001) Biologically interesting elements abundance in the Galaxy

9. 2nd Brazilian COROT Workshop - Ubatuba, Nov 6 2005 Stellar habitable zone R Main assumptions: Surface H 2 O for ~ Gyear, geological activity, CO 2 -H 2 O-N 2 atmosphere, B-field, climate stability, resistance to catastrophes for ~ Gyear

10. 2nd Brazilian COROT Workshop - Ubatuba, Nov 6 2005 In the early Earth: Miller & Urey, 1961

11. 2nd Brazilian COROT Workshop - Ubatuba, Nov 6 2005 Saladino et al., Chem. Biochem, 2004 Images´ source: http://www.whfreeman.com/life/update/ Pre-cellular life... Where does it come from? Nucleic acids required! But NO NUCLEIC ACIDS were found in Miller & Urey experiment. How could they be formed? Polymerisation of cyanide, which can be readily formed in a primitive atmosphere! So what? This still doesn't look much like a nucleic acid! However, the tetramer can be rearranged as follows:

12. 2nd Brazilian COROT Workshop - Ubatuba, Nov 6 2005

13. Pathways for biomolecule formation in space: the glycine case - Environment  1 Ori C ORION M42 TRAPEZIUM - HST 2003 Young stars T  ~ 30000K  X-rays Lx ~ 2 x10 32 erg s -1 (Chandra) n e ~ 5000 ne MI  Excitation of rotational- vibrational levels 

14. 2nd Brazilian COROT Workshop - Ubatuba, Nov 6 2005 Pathways for biomolecule formation in space: the glycine case - Model Tielens & Hollenbach (1985) ApJ 291, 747 Schulz etal 2001 ApJ, 549, 4441  FUV ~ 10-100 erg cm -2 s -1 n gas ~ 10 4 -10 5 cm -3 (10 7 -10 3 cm -3 ) T ~ 50-200 K (10 - 1000 K) PDRs Typical Features

15. 2nd Brazilian COROT Workshop - Ubatuba, Nov 6 2005 Measurements in space Acetic acid Formic acid NH 2 CH 2 COOH + (-H 2 O) methanolamine + Methylenimine Ammonia + (-H 2 ) Formic acid ice/gas ratio ~ 10000! Low resistence to radiation field? Which pathway is more probable? Formation via ice or gas phase? + (-H 2 O; -H) Protonated methanolamine + (-H 2 O; -H) Protonated Hidroxilamine Ehrenfreund et al 2001 JGR, 106, E12, 33291; Whittet et al 1996 A&A 315, L357

16. 2nd Brazilian COROT Workshop - Ubatuba, Nov 6 2005 Results from space Liu etal 2002 Apj 576, 255 (~2 x 10 15 cm 2 ) Remijan etal 2002 ApJ 576, 264 Kuan etal 2004 ASR, 33, 31 (~6x 10 15 cm 2 ) Through acetic acid Through formic acid

17. 2nd Brazilian COROT Workshop - Ubatuba, Nov 6 2005 Results from collisions at LNLS

18. 2nd Brazilian COROT Workshop - Ubatuba, Nov 6 2005 H C N Recent detection of a PANH in the IR Hudgins et al. ApJ, 2005 Spitzer detected PANHs in various galaxies, besides our own. First direct evidence for the presence of a prebiotic interesting compound in space. Presence of N is essential in biologically interesting compounds (clorophyle). The presence of a planet is no longer necessary for the formation of a PANH. Caffeine

19. 2nd Brazilian COROT Workshop - Ubatuba, Nov 6 2005 Porto de Mello et al., Astrobiology, 2005 Astrobiologically interesting stars and planets Explore the star/planet contrast in the thermal IR (Des Marais et al 2002, Segura et al 2003) Thermal IR CO 2 15  m O 3 9.6  m H 2 O: 6.3  m + 12  m band to microwaves CH 4 7.7  m Window at 8-12  m: surface temperature Color temperature + flux = radius (problems with clouds)

20. 2nd Brazilian COROT Workshop - Ubatuba, Nov 6 2005 Any alternatives at this point??? Other liquids may define other biochemistries Ammonia (Jupiter satellites), methane/ethane (Titan), nitrogen (silicon-oriented) Light (mostly IR) on the surface of Titan may allow photosynthesis-like processes, even at low temperatures. Chemolitotrophy possibly available in any liquid environment (Galilean satellites).

21. 2nd Brazilian COROT Workshop - Ubatuba, Nov 6 2005 Water-based oceans Other liquid possibilities OUR SOLAR SYSTEM´S LIQUID POSSIBILITIES water/ammonia (surface lakes) water/ammonia (subsurface) methane/ethane (surface lakes) nitrogen (surface) nitrogen (subsurface)

22. 2nd Brazilian COROT Workshop - Ubatuba, Nov 6 2005 Criptoendoliths Thermophile bacteria Hidrotermal vents Hot geisers and volcans Extremophiles survival chart Antarctica Temperature: -15° C < T < 230° C 0 < pH < 12 0 < Pressure < 1200 atm No mandatory oxygen-based metabolism 20-40 Myears of dormancy 2 ½ years in space, at 20 K, with no nutrients, water and exposed to radiation ( Strep. Mitis)

23. 2nd Brazilian COROT Workshop - Ubatuba, Nov 6 2005 What do we suggest? Carbon based, DNA-like search, in planetary systems –Targeting small constituints of organic compounds – IR/X (Pilling et al., A&A 2005) –Targeting PANHs – IR (Hodges et al., ApJ 2005) Other alternatives (chemical/physical) –Other liquids/fluids demand a different chemistry (not CHON based) due to thermodynamical requirements (Bains, Astrobiology 2005). –Self-sustained ability to disturb a local environment (Bains, Astrobiology 2005).

24. 2nd Brazilian COROT Workshop - Ubatuba, Nov 6 2005 WHERE IS DNA OR ANY OF ITS RELATIVES? The end… … or the beginning?????