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SKA and the Cradle of LifeFormation of Planets and Search for Extraterrestrial Life

Marc Audard (U of Geneva)Swiss SKA days, June 21, 2019

Slides from I. Jimenez-Serra & D. Johnstone with a personal flavour

SKA Big Questions

SKA Cradle of Life

• TheCradleofLife&Astrobiology– Howdoplanetsform?Arewealone?

• Strong-fieldTestsofGravitywithPulsarsandBlackHoles– WasEinsteinrightwithGeneralRelativity?

• TheOriginandEvolutionofCosmicMagnetism– Whatistheroleofmagnetismingalaxyevolutionandthe

structureofthecosmicweb?• GalaxyEvolutionprobedbyNeutralHydrogen

– Howdonormalgalaxiesformandgrow?• TheTransientRadioSky

– WhatareFastRadioBursts?Whathaven’twediscovered?• GalaxyEvolutionprobedintheRadioContinuum

– Whatisthestar-formationhistoryofnormalgalaxies?• Cosmology&DarkEnergy

– Whatisdarkmatter?Whatisthelarge-scalestructureoftheUniverse?

• CosmicDawnandtheEpochofReionization– Howandwhendidthefirststarsandgalaxiesform?

Cradle of Life Science Themes

1) How do rocky planets form?2) How did life originate?

3) What are exoplanets like?

4) SETI project

• Formation of rocky cores of planets via grain growth and settling

How Do Rocky Planets Form?

SKA Cradle of Life 4

Ned Wright - UCLA

Hope Ishii - UH

• Formation of rocky cores of planets via grain growth and settling



Testi et al. 2014 Hoare et al. 2015

SKA covers the right λ’s to probe cm-sized grainsmatching beams of

40 mas≈4 au radius of snow line at 100pc

à measure strength and and spectral index

Opacity curve

SKA1-MID

• Flattening of the spectral index has been observed in discs



AS209 Dust traps help overcome grain growth barriers è‘spiral density waves’

van der Marel et al. (2016)

Perez et al. 2012, 2015; Tazzari et al. 2016

• Using SKA to observe continuum emission for dust in discs



SPH simulationGravitationally Unstable Disk

(Run2 from Hall+2017)

Mdisk=0.25 MoM*=1 Mo

50 au

t = 4100 yrs

George

Ringo

Column Density N(H2) (Hall+2017; Ilee+2007)




40 mas beam@12 GHz

SKA-Mid Band 5 (64 dishes)

Credit: D. Quenard, C. Hall, J. IleeSPH simulation

Gravitationally Unstable Disk (Run2 from Hall+2017)

Mdisk=0.25 MoM*=1 Mo

distance = 100 pc

1000 hr integration

Peak= 19 µJy/beam (Tb=115 K) Noise= 0.07 µJy/beam (Tb=0.4 K) 50 au

Witnessing the formation of planets




@12 GHz

SKA-Mid

Credit: D. Quenard, C. Hall, J. IleeALMA 1.3 mm

MAPPING OF β ACROSS THE SNOW LINE OF WATER

40 mas beam

50 auTobin+2016




@12 GHz

SKA-Mid

Credit: D. Quenard, C. Hall, J. IleeALMA 1.3 mm

MAPPING OF β ACROSS THE SNOW LINE OF WATER

40 mas beam

50 auDSHARP (Andrews+ 2018)

Intermediate to high optical depths at mm

• From the ISM to the Origin of Life

How Did Life Originate?


35 mas x 40 mas beam

Planetary systems

Protoplanetary disks

Complex Organics (COMs)

How complex can organic chemistry become in the ISM and disc?Pre-biotic species!!

?Molecular clouds(Pre-stellar Cores)

• Complex Organic Molecules (COMs) … in Space



COMs are carbon-based compounds with >6 atoms (Herbst & van Dishoeck 2009)

• Complex Organic Molecules (COMs) … in Space



Glycolaldehyde(CH2OHCHO)

Amino Acetonitrile(NH2CH2CN)

Prebiotic COMs: species believed to be involved in the processes leading to the origin of life

Formamide(NH2CHO)

Simplest naturally occurring amide containing all elements needed for the synthesis of bio-molecules (Saladino+12,15)

• Formamide undetected in discs: SKA will be a pre-biotic COM detector



50 au

Simulations of NH2CHO (gas & solid) in the disk

SPH simulation (Hall+2017; Ilee+2007)+

chemistry of NH2CHO (Quenard+2018a)

Gas-phase NH2CHO (Quenard+2018b)

• Formamide undetected in disks: SKA as a pre-biotic COM detector



Simulations of NH2CHO (gas & solid) in the disk

SPH simulation (Hall+2017; Ilee+2007)+

chemistry of NH2CHO (Quenard+2018a)

distance = 100 pc1000 hr integration

Peak= 87 μJy/beam (Tb=530 K) Noise= 7 μJy/beam (Tb= 40 K)

t = 4100 yrsGas-phase NH2CHO with SKA1

40 mas beam

50 au

NH2CHO transition at 13.489 GHz

Credit: D. Q

uenard, C. Hall, J. Ilee

• Detection of pre-biotic COMs will be challenging



Problems:• High spectral line densities at mm/sub-mm l’s Þ Line blending/confusion!!• Broad linewidths (a few to some km s-1) Þ Line identification problematic

interferometry reduces linewidths

cm l’s are cleanerSKA

Belloche+2013Rest Frequency (MHz)

SgrB2(N) & SgrB2(M)

Tmb

(K)

• Planet dynamos è large-scale Bmag è magnetospheres– Magnetospheres may be key for habitability of planets …

• Low-frequency (~50 MHz) bursts seen from Jovian planets– Cyclotron-Maser Instability Emission (CMI) --- see also activity in brown dwarfs!

What are Exoplanets like?


SKA1-LOW

• Planet dynamos è large-scale Bmag è magnetospheres



Zarka et al. 2015

Earth’s ionospheric cutoff

metric-decimetric synchrotron

CMI, auroral, Io-induced




Zarka et al. 2015

What can we learn??

® Magnetic field strength : planet interior structure® Tilt of magnetic axis® Rotation and revolution periods® Orbit inclination® Stellar wind activity® Presence of exo-moons?




SKA1-LOW, sensitivity improved by a factor ~8

Jupiter-like planet could be detected to ~10 pc

~200 known stars and ~35 known

exo-planets within this volume !

Zarka et al. 2015

Max emission frequency

Searching for Extraterrestrial Life


• Known Technology Detection Limits …

Searching for Extraterrestrial Life


Siemion et al. 2015(tintegration = 60 min, SNR = 12)

§ SKA1: high-power airport radars detectable for >104 stars

§ SKA2: low-power TV and radio stations detectable for a fewnearest stars

Volume-limited search

Long range Aircraft Radar 1017 erg/s

High power TV and radio5x1012 erg/s

Cradle of Life Key Science Projects


KSP 1) Young Stellar Cluster Deep Field – Mapping β across snow lines

² Oph A star-forming cluster : 2/3 Class 0, 7 Class I, 12 Class II² 1000 hours in SKA1-Mid (Band 5, @12 GHz)² Angular resolution ~ 40 mas, i.e. 5 au at 125 pc

² Additional Science: Pre-biotic COMs, Jets, 6D Tomography, Magnetic Flaring

KSP 2) Stars, Planets and Civilizations

² Key Obs # 1 (SKA1-LOW): All sources within 25 pc è 2500 hours

² Key Obs # 2 (SKA1-LOW): Selected sample (>25 pc) è 1500 hours

² Key Ob # 3 (SKA1-LOW): Search for low Galactic latitudes è 833 hours

² High commensality with SWGs “Our Galaxy”, “Epoch of Reionization”, “Cosmology” and “Transients”

The Cradle of Life Working Group

+ 33 associate members from 15 countries

Cradle of Life Science Themes

1) How do rocky planets form?2) How did life originate?

3) What are exoplanets like?

4) SETI project

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