Julian Chela-FloresJulian Chela-FloresThe Abdus Salam ICTP, Trieste, ItaliaThe Abdus Salam ICTP, Trieste, Italiaandand Instituto de Estudios Avanzados, Caracas, Instituto de Estudios Avanzados, Caracas, Republica Bolivariana de VenezuelaRepublica Bolivariana de Venezuela

TThe Origins: how, when and where it all startedhe Origins: how, when and where it all started , , Accademia Nazionale dei Lincei. Centro Linceo Interdisciplinare Accademia Nazionale dei Lincei. Centro Linceo Interdisciplinare ““Beniamino SegreBeniamino Segre””, , Roma, 22 May 2006Roma, 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, India2. ICTP, Trieste and IDEA, Caracas, Bolivarian Republic of Venezuela3. 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.

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Life on exoworlds The Earth-like worlds (ELWs: planets and exomoons)

2

Relative sizes of dwarf stars

GV5: Kepler 22

MV3:Gliese 581

3

Red dwarfs Red dwarfs Planets within their HZPlanets within their HZ

Stellar class Luminosity (f) l/l0

Examples An exoplanetin a red dwarf

HZ M0Ve

V: luminosity class of a main-sequence star

e: with emission line present

7.2% Lacaille 8760 —

M1V 3.5 % Groombridge 34 —

M2V 2.3% Lalande 21185 —

M3V 1.5% Gliese 581 Gliese 581 c (5ME)

Gliese 581 d (6ME)

M4V 0.55% V374 Pegasi —

M5.5Ve 0.22% Proxima Centauri — 4

Orbital period

5

The habitability zone of red dwarfs is indeed closer to the star

Kepler-22b: Kepler-22b: An ELW (a planet) around a yellow An ELW (a planet) around a yellow

dwarfdwarfG5V

G2V

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Orbital period

1 yearless 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

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Kepler: ELW from Kepler: ELW from transitstransits

Preliminary parameters of ELWs Transits from the Kepler Mission

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Probing exoatmospheres will be possible with the Kepler successors: (a) future missions and

(b) future instrumentation

or their Habitable Exomoons

(or exomoon)

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Future Missions:Future Missions:

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NASA’s Fast INfrared Exoplanet Spectroscopy Survey Explorer

(FINESSE)

ESA’s Exoplanet Characterisation Observatory

(EChO)

NASA’s Transiting Exoplanet Survey Satellite (TESS)

Future instrumentationFuture instrumentation

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James Webb Space Telescope The Giant Magellan Telescope

Distribution of life in Distribution of life in the the universeuniverse

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Systems (astro)biologySystems (astro)biologySystems 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 CO2, N, a small fraction of O2, water into oxygenic atmospheres.

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The Great Oxidation Event (GOE)in the habitability zone of the solar system

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An analytic model

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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.

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Parameters

The luminosity of the ELW, the luminosity of the Sun, t the current time, and t0 is the time at which biogenic gas started forming in substantial amount on Earth.

In the expression for CO2 we have an additional parameter taking into account that not all of it will be converted into O2 (other processes such as photorespiration will generate some additional CO2).

The analytic model

A GOE in an ELW orbiting a red dwarf.

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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

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Fraction of non-biogenic gas ELWs orbiting a red dwarf

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Worlds around red dwarfsMuch older than the Earth?

Credit: Dressing& Charbonneau

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Setting the time originSetting the time origin

Stars Stellar classification

Estimated main-sequence

lifetimes (Gyrs)

Presence of exoplanets

The Sun G2 10 Earth (in HZ)

Kepler 22 G5 13 Kepler 22b (super-Earth in HZ)

93 Her K0 18.4 No

Upsilon Boötis K5.5 45.7 No

VB 10,van Biesbroeck

1944

M8V 104 VB 10b(not in HZ,

a cold Jupiter)21

An exoplanet older than Earth Orbits around red dwarfs

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Habitability could have Habitability could have preceded terrestrial lifepreceded terrestrial life

Our own tiny Kepler Our own tiny Kepler environment environment

is less than 300 light years.is less than 300 light years.

With SETI the cosmic With SETI the cosmic environment accessible byenvironment accessible by 2020 should be about three 2020 should be about three times the Kepler range, about times the Kepler range, about 1000 light years.1000 light years.

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Additional instrumentation Additional instrumentation issues issues

(further insights from the neighbouring moons) (further insights from the neighbouring moons)

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Not incorporated in the JUICE payload

Chela-Flores, 2010, Int. J. Astrobiol.

JUICE

SummarySummary 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