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Assembling the puzzle

From Earths to Super-EarthsHitran to the rescue...

“Good planets are hard to find” Bracewell

Lisa KalteneggerHarvard-Smithsonian Center for Astrophysics

HITRAN Conf, June 22th 2008

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Planets... The story so far...

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New worlds in our sky... 300+shadows of weird worlds...

What can we tell?

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The KEY... Transiting planets

Torres 2008

Fortney, 2007Sasselov 2007

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Weather forecast on Giant exoplanets? Atmosphere by transits... HD189733b

Tinetti et al 2007

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WHY ?

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The Pale Blue Dot

Voyager image, 400 billion km away

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Earth IR-emission

TES data; Christensen 2004

Kaltenegger, Traub, Jucks 2007 (ApJ)

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Line of Evidence

WHAT KIND

INTERIOR

ATMOSPHERE

LIFE ?

Density ?(radius/mass)

Plate tectonics?Ocean/land?

What chemistry?What star ? HZ ?

What biota?

FORMATION Formation Models

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Line of Evidence

FIND

INTERIOR

ATMOSPHERE

LIFE ?

SPECTRAL FINGERPRINT

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add

OUTLINE CODES

• Climate (Kasting, Segura, Pavlov)

• Photochemistry (Segura, Kasting)

• Radiative Transfer (Traub, Jucks)

Planet interior & outgassing

Cloud physics (CO2 & H2O)add

Kaltenegger et al 2007

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Signs Of Life On An Earth-like Planet

Vegetation

Plantproduct

Plant life

Bacteria

observed

WaterOxygen

Carbondioxide

Methane Nitrousoxide

Ozone

Needed for life Primordial;

& bacteria product

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Selsis 2007

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Spectral features IR & Is there Take out ?

Traub & Jucks, AGU, 2002; Des Marais et al. 2002, Selsis 2003, Kaltenegger 2007

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Atmosphericescape

OutgassingEarly or continuous

Geochemical recyclinge. g. carbonate silicate cycle

Biological processing

photochemistry

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LIFE

LIFE

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Selsis (data Kasting et al 93)Update Kaltenegger & Segura (prep)

The Test...The possibilities...Characterizing planets

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Habitable Zone... Goldilocks Zone

Selsis, Kasting et al 2007; Kaltenegger & Selsis 2007

19Paillet et al., in prep

TPF-CNew World Finder

CIS for Exoplanets: Spectral Fingerprints

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Earth part of the puzzle...

& a universe full of possibilitiesSontin et al 2007Leger et al 2004

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How to make water from a H2-rich atmosphere ?

Reduction of Fe-bearing silicates by H2 (Sasaki, 1990)

For fO2 ≤ core formation

H20/H2 ~ 0.1(Solar nebula : 6 x 10-4 Delivery?)

H2O vapor promotes greenhouse: Earth’s temp. as high as 4800 K

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Earth Evolution over geological time

Kaltenegger et al 2007 ApJ

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Continuous habitable zone

Goldilocks ZoneGl 581c... HOT, Gl581d COLD

Selsis et al 2007, Kaltenegger et al 2008, Seager et al 2008, Miller-Ricci et al 2008,...

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Super Earth around M star 3400K

Tidally locked planet1: day (60%) night side (40%)

2: day (75%) night side (25%)

3: day (85%) night side (15%)

Kaltenegger et al 2008 (in prep)

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Super Earth around M star 3400KTidally locked planet (rapidely rotating planet comparison line (shown in grey))• Scenario 3: high heat transport from day (85%) to night side (15%)

Kaltenegger et al 2008 (in prep)

CO2

O3

CH4H2O

H2O

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Transits... Pushing the limits

Kaltenegger, Traub, Jucks 2008 (sub)

Radius +/- ~ 0.06%

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Transits... Detecting habitable atmospheres

Kaltenegger, Traub, Jucks 2008 (sub)

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Hitran Shopping list• Near-IR lines (CH4)• Line profile (especially wings - Transits)• Self broadening... Line broadening • High atm pressure (< 3 bar)

– (= high gravity on Super-Earths)

• Transits probe upper Earth atmosphere mainly• Warming and cooling of atmosphere

– e.g. dense and early Earth atmospheres– …

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LIFE

LIFE

LIFE

SUPER EARTHS...

opportunity & challenge

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Habitabitity of Super Earths Gl581dGl 581d: Earth Amtosphere, 2.63 bar, 1.8x Earth gravity. M star 3200KScenario 1: no heat transfer day & night side (freeze out on dark side)Scenario 2: Planet rapidely rotating like Earth (same temperature day and night side)Scenario 3: Low heat transfer between day (75%) & night side (25%), no freeze out

Kaltenegger et al. 2008 (in prep)