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Evolution of the universe: From Astrophysics to Astrobiology. Systems astrobiology for a reliable biomarker on exo-worlds. Julian Chela-Flores The Abdus Salam ICTP, Trieste, Italia and Instituto de Estudios Avanzados, Caracas, Republica Bolivariana de Venezuela
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Evolution of the universe: • From Astrophysics to Astrobiology Systems astrobiology for a reliable biomarker on exo-worlds Julian Chela-Flores The Abdus Salam ICTP, Trieste, Italia and Instituto de Estudios Avanzados, Caracas, Republica Bolivariana de Venezuela The Origins: how, when and where it all started, Accademia Nazionale dei Lincei. Centro Linceo Interdisciplinare “Beniamino Segre”, Roma, 22 May 2006 Julián Chela-Flores The Abdus Salam ICTP, Trieste, Italia and Instituto de Estudios Avanzados, Caracas, Bolivarian Republic of Venezuela EGU General Assembly 9 April 2013 EGU2013-1327-1
Life on exoworlds The earth-like worlds (ELWs: planets and exomoons)
Co-workers and collaborations Aranya B. BHATTACHERJEE Department of Physics, ARSD College, University of Delhi, New Delhi, India, Suman DUDEJA Department of Chemistry, ARSD College, University of Delhi, New Delhi, India. Moises SANTILLAN Computational Systems Biology Laboratory, Centro de Investigación y Estudios Avanzados del IPN, Unidad Monterrey, Mexico UK Penetrator Consortium
Census of Kepler mission planet candidates (2013) Credit: Kepler, NASA
Orbital period The habitability zone of red dwarfs is indeed closer to the star M3V, Constellation of Libra
Orbital period 1 year less transits contrast less favorable 10-25 days more transits, contrast more favorable for the present observations (Kepler), as the habitability zone is closer to the star
or Their Habitable Exomoons Credit: based on Dressing& Charbonneau HD 209458 Constellation Pegasus. yellow dwarf, G0V HD 209458 b hot Jupiter/Na atmosphere To understand biogenic exoatmospheres we wait for the Kepler’s successors: (a) Future missions, (b) Present and future instrumentation, and (c) Additional instrumentation issues for ELWs that are exomoons
Future Missions ESA’s Exoplanet Characterisation Observatory NASA’s Fast INfrared Exoplanet Spectroscopy Survey Explorer (FINESSE) NASA’s Transiting Exoplanet Survey Satellite (TESS)
Present and future instrumentation High Accuracy Radial Velocity Planet Searcher (HARPS, ESO, La Silla) The Giant Magellan Telescope, with the G-CLEF Spectrometer The 40-metre class E-ELT James Webb Space Telescope
Instrumentation issues for ELWswhen the venue for life is an exomoon Not incorporated in the JUICE payload Biogeochemistry is a useful science Chela-Flores, 2010, Int. J. Astrobiol.
The Great Oxidation Event (GOE) in the habitability zone of our solar system
Systems (astro)biology • Systems biology is used in biomedical research, systems are, for instance, cells and perturbations are drugs. In our special case of systems astrobiology, • Instead of systems of cells, we have systems of ELWs. • Perturbations are not drugs perturbing cells, but rather autochthonous biological perturbations of the primary planetary atmosphere.
Systems (astro)biology • Models of systems of ELWs will be possible with responses to biogenic perturbations that are under two constraints: • 1. The perturbation is due to communities of prokaryotic photosynthetic aerobes, and anaerobes that are constrained to remain microbial waiting for an evolving magnetic core that will preserve planetary atmospheres and hydrospheres from stellar wind erosion (Tarduno et al). • 2. The perturbation, while evolving, shifts the primary atmosphere into anomalous oxygenic atmospheres after the oxidation of the planetary surface is completed (Catling et al).
An analytic model Assumptions: • We assume the universality of biology. • In particular, we assume evolutionary convergence.
An analytic model Parameters: • The current and starting abundance of biogenic gas (oxygen) and non-biogenic gas (carbon-dioxide) in an ELW of the red dwarf. • The luminosity of the red dwarf hosting an ELW and the luminosity of the Sun. • The current time, and the time at which biogenic gas started forming in substantial amount on Earth. • A parameter taking into account photorespiration that will generate some additional CO2. (In a process of photosynthesis, not all the CO2 will be converted into O2.)
An analytic model Allows a prediction for: • A GOE in an ELW orbiting a red dwarf. • The abundance of the non-biogenic gas in an ELW orbiting a red dwarf.
ELWs orbiting a K star (Fraction of non-biogenic gas) Exoplanet of a K star (40% L☉) 18
ELWs orbiting an M dwarf (Fraction of non-biogenic gas)
ELWs orbiting a K star (Fraction of non-biogenic gas) Exoplanet in the HZ of a K star (40% L☉)
ELWs orbiting a red dwarf (Fraction of non-biogenic gas)
Systems (astro)biology • After the GOE event in an ELW in the HZ of a red dwarf, further steps in evolution are possible: • The microbial communities can evolve into eukaryotes that are able to turn into complex life (multicellular). • With sufficient time after the GOE has elapsed (> 2-3 Gyrs), there will be strong selection advantage for the evolution of intelligence.
ELWs around red dwarfs are potential hosts to organisms older than terrestrial ones Credit: based on Dressing& Charbonneau This suggests resetting the origin of time for the ELW at the big bang
Setting the origin of time at the Big Bang for ELWs older than Earth (orbiting around red dwarfs) Exoplanet in the HZ of a K star (40% L☉)
Setting the origin of time at the Big Bang for ELWs older than Earth (orbiting around red dwarfs)
Habitability could have preceded terrestrial life • Our so far tiny Kepler environment is less than 300 light years across (estimated to be ≈ 0.003 of the whole celestial sphere). • With SETI the cosmic environment accessible by2020 should be about three times the Kepler range, about 1000 light years. • If the evolution of intelligent life is a possibility, ELWs in the HZ of ancient red dwarfsbecome additional observable targets that radio astronomers with their ever more sensitive instruments have been following up for over half a century.
Summary • Our attention is restricted to red dwarfs of which about 6% are expected to have Earth-like planets (Dressing and Charbonneau, 2013). • Oxygen and carbon dioxide are the only exo-bioindicators that we considered at this stage. • Our predictions are biology-dependent: • Universal biology (evolutionary convergence). • Testing the predictions for biogenic perturbations of ELWs is possible with forthcoming new missions and with future Earth-bound instrumentation, not excluding radio telescopes, such as the SKA.