origin & evolution of habitable planets: astronomical prospective d.n.c. lin university of...

Origin & Evolution of Habitable Planets:Astronomical Prospective

D.N.C. LinUniversity of California, Santa Cruz, KIAA, Peking University, with

Pathways towards Habitable Planets Barcelona, Spain

September 14th, 2009

S. Ida, J.L. Zhou, K. Kretke, C. Baruteau, S.L. Li, K. Schlaufman, H. Yi, J. Yan, C. Agnor, R. Laine

17 slides

Key Questions

• Are we alone? (In search of island planets)

• Are we special? (Similarities & diversities)

• How did we get here? (Origins & Evolution)

• Where is ET ? (Environment & biosignatures)

• Theorey of biology (From anthropic principle towards a set of deterministic laws).

2/17

Milestones

• Conceptual nebula hypothesis

• First observational discoveries

• Characterization & calibration

• Constraints of theoretical models

• Strategies for future searches

3/17

Why study gas giants first?• Easy to detect: Stimulus of different search methods• Highlight theoretical challenges: rapid formation, limited retention, & diverse evolution • Missing link to rocky planets: cores and composition• Environmental perturbers: shakers and movers of dynamical architectures• Signposts of habitats? rocky-planet oasis or desert

4/17

Ubiquity of gas giants

Protostellar

diskstransits

Radial

velocity

Solar system exploration

meteoriti

c

microlensing

Planetary

systems

5/17

AO

cvcv

Ground based limitationsGround based limitations

orbital radius [AU]

Pla

net

mass

[M

]

EarthEarthVenusVenus

MercuryMercuryMarsMars

SaturnSaturn

UranusUranus NeptuneNeptune

JupiterJupiter

directdirectimagingimaging

1 100.1

1

0.01

100

young stars, young stars, ABAB

6/17

gas giants

planetesimals

©Newton Press

cores

protoplanetary disk:H/He gas (99wt%) + dust grains (1wt%)

core accretion

gas envelope contraction

runaway gas accretion

>100M

> 5-10M

coagulation of planetesimals

terrestrialplanets

gas accretion onto cores

type I migration

type II migration

Population synthesis model Population synthesis model Ida & Lin (2004a,b,2005,2008a,b)Ida & Lin (2004a,b,2005,2008a,b)

, aini =(integration on 109y)⇒ Mp, afinal

7/17

Migration & retention

8/17

Calibration of theoretical modelsSnow line accumulation of dust and embryos

9/17

Hot Jupiters & Super Earths

10/17

Tidal &

magnetic

interaction:Inflation and m

ass losses

Stellar spin

Scattering &Kozai effect

Secular & resonant interaction in multiple systemsFormation time/space separation.Preservation of resonances

11/17

Formation after 60 Myr

Formation on 30-60 Myr

Relativistic detuning in Arae

If more than 3 giant planets form on circular orbitsOrbit crossing starts on tcross

One is ejected. The others remain in stable eccentric orbits.

inner one: radial velocity outer one: direct imaging

tcross

Origin of eccentric planets: jumping jupiterOrigin of eccentric planets: jumping jupiterWeidenschilling & Marzari (1996), Lin & Ida(1997),Zhou et al (2007)

Solar system: 2 giants

stable

t cro

ss [y

r]

Δa [rH]

12/17

Orbital radius [AU]Orbital radius [AU] 0.01 0.1 0.01 0.1 1 101 10

P

lane

t mas

sPl

anet

mas

s [[M

]]

33

3030

300300

30003000

RV obs. RV obs. limitlimit

Gas giantsGas giants

Pushing the discovery frontiers (RV)Pushing the discovery frontiers (RV) 　　

Close-in super-Earths: Close-in super-Earths: ~30 % of FGK dwarfs close-in gas giants (hot jupiters): ~ a few % gas giants: ~10 %

Super-Super-EarthsEarths

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Super-Earths without gas giants

13/17

Failed cores(mostly ices) vsIn situ mergers(mostly rocks)

What will Kepler see?

Exciting prospectsExciting prospects

orbital radius [AU]

Pla

net

mass

[M

]

VenusVenusEarthEarth

MarsMarsMercuryMercury

SaturnSaturn

UranusUranus NeptuneNeptune

JupiterJupiter

TransitTransitfrom spacefrom space

Corot, KeplerCorot, KeplerTESS (2013?)TESS (2013?)

1 100.1

1

0.01

100

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Summary　　　　

extrasolar gas giantsextrasolar gas giants Observational characterization:Observational characterization:

Diversity: migration & dynamical Diversity: migration & dynamical instabilityinstability

Stellar mass/metallicity dependenceStellar mass/metallicity dependence Theory: disk mass & migration play key rolesTheory: disk mass & migration play key roles

next challenges next challenges (both observation and (both observation and theory)theory) gas giants gas giants

Dynamical structure in multiple systemsDynamical structure in multiple systems Diversity: atmosphere, structure, & Diversity: atmosphere, structure, &

compositioncomposition super-Earthssuper-Earths

Close-in super-Earths are abundantClose-in super-Earths are abundant Habitable planets around M dwarfsHabitable planets around M dwarfs Long-term stability of planetary systemsLong-term stability of planetary systems

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Future prospects

3/6 17/17