Presentation on theme: "Julian Chela-Flores Julian Chela-Flores The Abdus Salam ICTP, Trieste, Italia and Instituto de Estudios Avanzados, Caracas, Instituto de Estudios Avanzados,"— Presentation transcript:
Julian Chela-Flores Julian Chela-Flores The Abdus Salam ICTP, Trieste, Italia and Instituto de Estudios Avanzados, Caracas, 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 Evolution of the universe: From Astrophysics to Astrobiology A. B. Bhattacherjee 1, J. Chela-Flores 2 and S. Dudeja 3 1. Department of Physics, ARSD College, University of Delhi, New Delhi, India 2. ICTP, Trieste and IDEA, Caracas, Bolivarian Republic of Venezuela 3. Department of Chemistry, ARSD College, University of Delhi, New Delhi, India FROM CHEMICAL EVOLUTION ON EARTH TO INSTRUMENTATION ISSUES FOR TESTING SYSTEMS ASTROBIOLOGY ON EXO-WORLDS International Workshop on Chemical Evolution and Origin of Life. ITT Roorkee, 21 – 23 March 2013. 1
Life on exoworlds The Earth-like worlds (ELWs: planets and exomoons) 2
Red dwarfs Planets within their HZ Stellar classLuminosity (f) l/l 0 ExamplesAn exoplanet in a red dwarf HZ M0Ve V: luminosity class of a main- sequence star e: with emission line present 7.2% Lacaille 8760— M1V3.5 % Groombridge 34— M2V2.3% Lalande 21185— M3V1.5% Gliese 581Gliese 581 c (5M E ) Gliese 581 d (6M E ) M4V0.55% V374 Pegasi— M5.5Ve0.22% Proxima Centauri— 4
Orbital period 5 The habitability zone of red dwarfs is indeed closer to the star
Kepler-22b: An ELW (a planet) around a yellow dwarf G5V G2V 6
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 7
Kepler: ELW from transits Preliminary parameters of ELWs Transits from the Kepler Mission 8
Probing exoatmospheres will be possible with the Kepler successors: (a) future missions and (b) future instrumentation or their Habitable Exomoons (or exomoon) 9
Systems (astro)biology Systems biology is used in biomedical research, but in our case of systems of ELWs, we single out perturbations to exoatmospheres, due to autochthonous biological processes producing anomalous abundances of oxygen. With sufficient data from Kepler successors models of systems (astro)biology will describe the structure of the systems (ELWs) and their response to perturbations. The expected perturbations would be due to biologic communities that shift the primary non-biogenic mixture of CO 2, N, a small fraction of O 2, water into oxygenic atmospheres. 13
The Great Oxidation Event (GOE) in the habitability zone of the solar system 14
An analytic model 15 Assumptions: We assume the universality of biology. In particular, we assume evolutionary convergence.
The analytic model The current and starting abundance of biogenic gas (oxygen) and non-biogenic gas (carbon-dioxide) in an ELW of the red dwarf. 16 Parameters The luminosity of the ELW, the luminosity of the Sun, t the current time, and t 0 is the time at which biogenic gas started forming in substantial amount on Earth. In the expression for CO 2 we have an additional parameter taking into account that not all of it will be converted into O 2 (other processes such as photorespiration will generate some additional CO 2 ).
The analytic model A GOE in an ELW orbiting a red dwarf. 17 Allows a prediction for: The abundance of the non-biogenic gas in an ELW orbiting a red dwarf. It suggests resetting the origin of time at the big bang.
Preliminary results ELWs orbiting a red dwarf 18
Fraction of non-biogenic gas ELWs orbiting a red dwarf 19
Worlds around red dwarfs Much older than the Earth? Credit: Dressing& Charbonneau 20
Setting the time origin StarsStellar classification Estimated main- sequence lifetimes (Gyrs) Presence of exoplanets The SunG210Earth (in HZ) Kepler 22G513Kepler 22b (super-Earth in HZ) 93 HerK018.4No Upsilon BoötisK5.545.7No VB 10, van Biesbroeck 1944 M8V10 4 VB 10b (not in HZ, a cold Jupiter) 21
An exoplanet older than Earth Orbits around red dwarfs 22
Habitability could have preceded terrestrial life Our own tiny Kepler environment is less than 300 light years. is less than 300 light years. With SETI the cosmic environment accessible by 2020 should be about three times the Kepler range, about 1000 light years. 23
Additional instrumentation issues (further insights from the neighbouring moons) 24 Not incorporated in the JUICE payload Chela-Flores, 2010, Int. J. Astrobiol. JUICE
Summary Most stars are red dwarfs and some host Earth-like planets. Oxygen and carbon dioxide are the exo-bioindicators considered in this work. Model predictions for exo-atmospheres have assumed: Universal biology (evolutionary convergence) Testing the predictions for the exoatmospheres of ELWs is possible with forthcoming new missions and with future Earth-bound instrumentation. 25