Nigel J Mason Physics & Astronomy The Open University, UK. Biosignatures on Exoplanets: The Identity of Life” Nigel J Mason Physics & Astronomy The Open University, UK. ESF Exploratory Workshop, held at EPS Mulhouse, 23- 25 June, 2009 Follow up (joint with COST Action CM0805 ; The Chemical Cosmos) Open University, January 15-17, 2010
Exoplanets One of the most exciting advances in modern astronomy Detecting and exploring ‘New Worlds’ Rapidly increasing data set
Exoplanets in the Solar Neighbourhood 65 light years
Detecting Life Remotely Pale Blue Dot Visible or IR radiation contain spectral fingerprint of planet’s surface or atmosphere: look for BIOSIGNATURES CO2
Rationale of workshops Next decade will be able to detect/explore exoplanet atmospheres. Earth-like exoplanets will be detected in larger numbers. So how to look for signatures of life ? First serious candidate for habitability: Gliese 581 d
Aims of workshops: How to look for life of an exoplanet What are the key biomarkers/bio-indicators ? What are their spectroscopic signatures ? Are these detectable (with current means) ? Are they masked by abiotic signatures ?
Results from workshops Identified possible biomarkers with characteristic molecular spectra/fingerprints. Different biomarkers = different exoplanet scenarios. So need for composite molecular spectra in different atmospheres. O2/O3 CH4 H2O CO2
Results from workshops Need to model different scenarios Use Earth as benchmark for chemistry and HISTORY Research intricately linked to knowledge of ‘origins of life’
Terrestrial exoplanets Magma Snowball Jurassic Early Mars Early Venus Jungleworld Desertworld Waterworld Superearth
Earth-in-Time Atmospheres Magma Hadean Archaean Proterozoic Snowball Atmospheric Composition Silicate CO2 CO2 N2 N2 Steam H2O N2 O2 O2 CO2
Factors affecting terrestrial atmospheres Size, Mass (gravity, pressure) Orbit (mean distance, eccentricity) Central star (spectral type) Atmospheric composition (greenhouse gases, photochemistry) Atmospheric mass (pressure) Ocean (hydrological cycle) Tectonics (volcanism, magnetism) Age (Photon flux, evolution) Biology (Emissions, CO2 cycle...)
Results from workshops We agreed some ‘models’
Biomarker abundances? Archaean atmosphere 2.5 billion years ago CO2 (x10,x100) CH4 (x10) O2 (x0.1, 0.01) UV (x100) Tsurface (30-80oC) Photon flux = 83% modern Biomarker abundances?
Proterozoic atmosphere 2.2 billion years ago CO2 (x5) CH4 (x2, x5) O2 (x0.1, 0.01) UV (x100) Tsurface (30-80oC) Photon flux = ~90% modern Biomarker abundances? (O3, N2O)
Snowball Earth atmosphere CO2 (x10) CH4 (x2) O2 (x0.1, 0.01) UV (x100) Biomarker abundances? (O3, N2O)
Jungleworld atmosphere High vegetation emissions High O2 (21-35%) Biomarker abundances? (O3, N2O)
Superearth atmosphere Earth composition Psurface e.g. 1bar, 2bar Biomarker abundances? (O3, N2O)
Results from workshops Need to test ‘models’ with laboratory mimics Can use existing apparatus that models Solar System planets but too many scenarios….
Results from workshops Community needs to converge on one or two exoplanet models to test vs laboratory data. Choice may come from observations or May design an agreed exoplanet -
Results/Future from workshops Workshops follow up Develop design of an agreed exoplanet for use in models and laboratory Use COST Action CM0805 to develop these scenarios further
Results/Future from workshops Two model exoplanets An Earth like exoplanet (a Super Earth) on which photosynthesis has established itself (with oxygen and ozone, N2O as biomarkers) and a pre-photosynthetic world in which methanogens are prevalent (which may also be closer to an early Martian world).
Follow up Through EU actions COST Action CM0805 (WG3) next meeting October 5-8 and December 5-7 ITN Lassie and new one in January 2011 VAMDC – research infrastructure Europlanet – well networked with Commission, ESA, EU Parliament
Publicity Planned exhibition in Brussels June 2011 Combining COST Action, Lassie and Europlanet EU in Space exploration Briefing to FP, MEPS and others (as part of International Year of Chemistry)
Acknowledgements Professor Ewa Suskiewicz (Co -Chair ESF Workshop) For slides and comment Dr Lee Grenfell DLR & TU Berlin
Why Exploratory workshop ? Reviewed options for different topics/requirements in 2008 ‘Exploratory’ – New science – ‘out of the box’ – not mature field, not results now ! So cant demonstrate ‘history’ – as in COST
Why Exploratory workshop ? Bring together diverse communities (Very important). Observations – yes but… Origins of life, Earth observation, technical and crucially Laboratory testing of models
Why Exploratory workshop ? How to be successful Specific outcomes – ask specific question (get multiple answers –not what we expected) Presentation but discussion after each with summary end of each session Follow up critical – having identified need to develop joint model could follow up and bring in other experts we found missing in workshop.
Why Exploratory workshop ? Past examples Ultracold Chemistry workshop (new area in 2004-5) – led to Eurocore (Euroquam) and ITNs field now developing rapidly with cold molecules now very topical