Property Trends

Exoplanet around a Sun-like Star
Planet Detection Timeline
exoplanets.org | 11/21/2013
Distribution
150
100
50
1990
1995
2000
2005
2010
First Publication Date
www.exoplanets.org
Exoplanet around a Sun-like Star
They are everywhere!
2.5
2.0
1.0
1.5
0
-50
0.5
DEC [Degrees]
50
0.1
1
10
RA [Hours]
Mass of Star [Solar Mass]
3.0
exoplanets.org | 11/21/2013
Eccentric Planets
Pass
Clos Very
e to
Star
Eccentricity
6
R
☼
3
R
☼
5yr
10yr
20yr
Diversity of Extrasolar Planets
Eccentric Giant Planets
Hot Jupiters
Jupiter
Solar
System-like
Analogs
Hot Jupiters
Giant Planets
Orbital Period (days)
www.exoplanets.org
P. Armitage
New Theories of Planet Formation
Illustration by E. Chiang; Adaptations E. Ford
Hot Jupiters via
Disk Migration
?
Illustration Adapted from E. Chiang
9
Hot Jupiters via
Planet Scattering + Tidal Circularization
GLS
Rasio & Ford 1996
Illustration adapted from E. Chiang
11
Eccentric Giant Planets via
Planet Scattering
GLS
Rasio & Ford 1996; Weidenschilling & Marzari 1996
Illustration Adapted from E. Chiang
Eccentricity Distribution Predicted by Planet Scattering
Many Planets
Three Planets
!
s
n
io )
t
i
d g
n terin
o
c at
l t sc
a
i
t
n i lane
i ”p
o
t t pure
s m“
u
b fro
Rot least
(a
0
0.4
0.8
e
Eccentricity
Juric & Tremaine 2007
0
0.4
0.8
e
Eccentricity
Chatterjee et al. 2007
Distance (AU)
Secular Evolution of Ups And
ra
a
rp
d
ra
a
rp
c
Eccentricity
d
c
Time (years)
Ford, Lystad, Rasio 2005; see also Malhotra (2002), Chiang et al. (2002); Barnes & Greenberg (2006); Veras & Ford 2009
Measuring Exoplanet Inclinations
• Tidal dissipation in the planet rapidly damps eccentricity
• Search for planets with inclination excited by strong scattering
(Chatterjee et al. 2008; Fabrycky & Tremaine 2007; Nagasawa et al. 2007)
Gaudi & Winn 2006
Projected Angle between
Stellar Rotation Axis & Orbit Normal
Stars & Hot-Jupiter’s can be Misaligned
Host Star Temperature (K)
Amaury Triaud; adapted from Winn et al. 2010
Launch of Kepler Mission
Planet Size (Earth Radii)
Orbital Period (days)
NASA/Burke et al. in prep
NASA / Burke et al. in prep
Hot Jupiters are Lonely
• 63 Hot Jupiters
• No other transiting
planets
• No TTV signals
• Consistent with
eccentricity excitation
followed by tidal
circularization
(Steffen et al. 2012 PNAS;
see Szabo et al. arxiv)
Hot Jupiters via
Planet Scattering + Tidal Circularization
GLS
Rasio & Ford 1996
Illustration adapted from E. Chiang
Hot Jupiters via
Disk Migration?
?
Illustration Adapted from E. Chiang
24
Innermost Planet Period Rank
Orbital Resonances Among
Multi-Planet Systems Disovered via RVs
55 Cnc
Period (days)
Fabrycky
Kepler-30: Coplanarity via Spot Crossings
Sanchis-Ojeda+ 2012
Extremely Compact
Multi-transiting
Planetary Systems
Fabrycky et al. 2012
Extremely Compact
Multi-transiting
Planetary Systems
TextHigher solid density close to staridea of minimum mass extrasolar nebula
(Laughlin et al. 2012, also see Hansen &
Murray 2012)
Inside-out planet formation
(Chatterjee & Tan)
Fabrycky et al. 2012
Extremely Compact Multi-transiting
Planetary Systems
Inside-Out Planet Formation
(i)
(ii)
dead
zone
MRI
zone
3
pebble drift
pebble ring
forms at P max
planet
formation
(iii)
(iv)
dead zone
retreat
Chatterjee & Tan 2013
Fig. 1.— Schematic overview of the stages of the inside-out planet formation scenario. (i) Pebble formation and drift to the inner disk.
Pebbles form via dust coagulation in the protoplanetary disk. Those with ∼cm–m sizes attain high radial drift velocities and quickly reach
the dead zone inner boundary, where they become trapped at the pressure maximum. (ii) Pebble ring formation. A ring of pebbles gradually
Very Tightly Packed Planetary Systems
Kepler-36b&c: Chaotic due to 29:34 and 6:7 MMRs!
Carter et al. 2012; Deck et al. 2012
Resonances in Kepler Multi-Planet Systems
– Predicted!
• Most near, but
not in resonance
• Near resonant
great for TTVs
– esp. closely
spaced pairs!
Rein et al. 2012;
Ford & Rasio 2008; Veras et al. 2012
Kepler Multi-Planet Candidates
Period Ratio
Total Planet Mass (MJup)
• Rarer than in
RV systems
Cumulative Number of Planet Pairs
RV Multi-Planet Systems
Planet Radius (REarth)
Number
Kepler’s Near Resonant Systems
Period Ratio
Fabrycky et al. 2012;
see also Rein et al. 2012; Ford & Rasio 2008; Veras et al. 2012
at closely
e the en-
Figure 1. Cumulative distribution of the period ratios in KOI systems with
multiple planets – solid (red) line: observed period ratios; long dashed line:
104 years;
and Veras
short dashed
line:
period
ratios
after see
migration
τ a &=Rasio
Rein
et al.
2012;
alsowith
Ford
2008;
et
al.
2012
period ratios after migration with τ a = 103 yr.
Downloaded fr
up allows
, the mi-scale τe .
gap in a
da, More Type I
cal value
Note that
the Type
ccentricmigration
has been
tified by
4). Tests
s precise
tep set to
ve shown
r or time
Kepler’s Near Resonant Systems
Kepler’s Near Resonant SystemsPeriod ra
5 ECCENTR
Figure 2. Cumulative distribution of the period ratios in KOI systems with
multiple planets – solid (red) line: observed period ratios; long dashed line:
−6 ; and
period
aftersee
migration
with stochastic
α =et10al.
Rein
et al.ratios
2012;
also Ford
& Rasio forces
2008;with
Veras
2012
short dashed line: period ratios after migration with stochastic forces with
−5
When planets m
ities rise. Eventu
and the eccentri
(Papaloizou 200
tricities to grow
If the combina
ios, as presented
period ratio dist
centricity distrib
parameters τ a =
with parameters
In Fig. 3 we p
our simulations.
103 yr, produces
resonance earlie
without stochast
curve (blue), sho
planets that do
eccentricity. Fin
Kepler’s Near Resonant Systems
resonant repulsion
The Astrophysical Journal Letters, 756:L11 (5pp), 2012 September 1
time because the planets form
large inertia. The prevalence of
short tRR systems spurs us to h
tRR in Figure 3 are results of
resonances are not primordial,
repulsion and three-body effec
Removing the colored circl
clear picture that most pairs
while pairs very close to reso
are shifted by a few percent to
4. DISC
Lithwick
Figure 3. Timescale for resonant repulsion to move the period ratio of Kepler
planet pairs by a distance |∆|, where ∆ is the observed fractional distance to the
et
al. first
2012;
see also
Ford
Rasio
2008;
closest
order resonance.
We adopt
KIC&system
parameters,
withVeras
updated
values for KOI-961 (red dots) from Muirhead et al. (2012). For tidal dissipation,
Q1 = 10 and k2 = 0.1. The lower panel zooms in to the resonant region. If
et
In this work, we investigate
excess of Kepler planet pairs ju
just inward of resonance. We p
sible for this asymmetry. Tw
eccentricities are weakly dam
1981; Lithwick & Wu 2008; P
dissipation damps away the p
eccentricities that are forced
dissipation. Planets are typica
on these forced eccentricities.
lows dissipation to continuous
Resonant repulsion pushes pa
al.side
2012
of resonance, and naturall
accumulate at a fractional dist
2
1/3
Eccentricities of Transiting Planets
via Transit Duration Distribution
• Consistent w/ RV distribution
• Smaller planets have smaller
eccentricities
• Subject to uncertainties in stellar
properties (A. Moorhead+ 2011)
Cool Host Stars
Teff < 5400K
A. Moorhead+ 2011; see also Dawson+ 2012, Kane+ 2012
Testing Planet Formation Theory with Kepler
Orbital eccentricities, inclinations & multiplicity are
key probes of planet formation:
• Eccentricity distribution (+ stellar densities) →
Transit duration distribution
• Inclination distribution + Frequency of multiple
planet systems (+ period distribution) →
Frequency of multiply transiting systems &
transit duration variations
• Frequency of multiple planet systems +
Eccentricity distribution (+ period distribution) →
Distribution of TTV signatures
One complex inverse problem!
(Observables, Desired Distributions, Both)
Inclination Dispersion (degrees)
Planet Multiplicity & Mutual Inclinations
Ragozzine
p(N;λ) == λλNNexp(-λ)
exp(-λ)/ /N!
N! (Poisson)
p(N;λ)
p(i;σ) = i / σ2 exp(-i2/2σ2) (Rayleigh)
Mean Number of Planets per Star (λ)
see also Lissauer+ 2011; Tremaine & Dong 2011; Fang et al. 2012
Period-Normalized Transit Duration Ratio
R. Morehead; see poster 343.04
R. Morehead in prep.; see also Fabrycky et al. 2012; Fang et al. 2012; poster 343.04
Testing Planet Formation Theory with Kepler
Orbital eccentricities, inclinations & multiplicity are
key probes of planet formation:
• Eccentricity distribution (+ stellar densities) →
Transit duration distribution
• Inclination distribution + Frequency of multiple
planet systems (+ period distribution) →
Frequency of multiply transiting systems &
transit duration variations
• Frequency of multiple planet systems +
Eccentricity distribution (+ period distribution) →
Distribution of TTV signatures
One complex inverse problem!
(Observables, Desired Distributions, Both)
Long-Term TTVs
Ford+ 2012
Kepler’s Multiple Planet Systems
Holman+ 2011; Batalha+ 2010; Torres+ 2010; Lissauer+ 2011; Cochran+ 2011; Ford+ 2012; Steffen+ 2012ab;
Fabrycky+ 2012; Fressin+ 2012; Muirhead+ 2012; Nesvorny+ 2012; Xie 2012; Orosz+ 2012
Kepler’s Multiple Planet Systems
Holman+ 2011; Batalha+ 2010; Torres+ 2010; Lissauer+ 2011; Cochran+ 2011; Ford+ 2012; Steffen+ 2012ab;
Fabrycky+ 2012; Fressin+ 2012; Muirhead+ 2012; Nesvorny+ 2012; Xie 2012; Orosz+ 2012
Kepler’s Multiple Planet Systems
Holman+ 2011; Batalha+ 2010; Torres+ 2010; Lissauer+ 2011; Cochran+ 2011; Ford+ 2012; Steffen+ 2012ab;
Fabrycky+ 2012; Fressin+ 2012; Muirhead+ 2012; Nesvorny+ 2012; Xie 2012; Orosz+ 2012
Kepler’s Multiple Planet Systems
Holman+ 2011; Batalha+ 2010; Torres+ 2010; Lissauer+ 2011; Cochran+ 2011; Ford+ 2012; Steffen+ 2012ab;
Fabrycky+ 2012; Fressin+ 2012; Muirhead+ 2012; Nesvorny+ 2012; Xie 2012; Orosz+ 2012
How Common are TTVs?
• First 16 months of Kepler data (Ford+ 2012):
– 39 – 175 TTV candidates
– 8% – 18% of suitable KOIs show TTVs
– More for multis & long period planets
• Planets Confirmed by TTVs: 73 of ~105
• Sensitivity to long-term TTVs grows ~t5/2
– Many more KOIs w/ TTVs in extended mission
Super-Earths or Mini-Neptunes?
Eric Lopez
Future Prospects for
Measuring Masses via TTVs
1 Earth-mass, 3:2 MMR, Kp=13
2 Earth-mass, 3:2 MMR, Kp=13
Ford
Detecting Small Planets w/ Large TTVs
Undetectable in 8 years
D
c
e
t
e
/
w
le
b
ta
w
e
N
s
m
ith
r
go
l
A
Detected despite any TTVs
w/ 8 years of Kepler data
Ford+ 2012
New Algorithms: Carter & Agol in prep; Moorhead+ in prep
Testing Planet Formation Theory with Kepler
Must combine many elements simultaneously:
• Detection efficiency/completeness
• Planetary systems
(not just superposition of individual planets)
• Variety of observational constraints
(e.g., RV, TTV, spectra, imaging, seismology)
• Observational uncertainties
• How planets were chosen for follow-up
observations or more detailed analyses
Future Space Missions
Direct Imaging & ALMA
Boley et al. 2012
ALMA: ESO/NAOJ/NRAO + HST: NASA/ESA
NASA, ESA, & Kalas (UC, Berkeley & SETI Institute)
Invite Students to Join the Hunt!
PlanetHunters.org
Invite Students to Join the Hunt!
PlanetHunters.org
Questions
NASA
Movie of Collapse &
Fragmentation
Movie of Collapse &
Fragmentation