origin & evolution of habitable planets: astronomical prospective d.n.c. lin university of...
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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
14/17
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
15/17
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
16/17
Future prospects
3/6 17/17