#55 Formation of close-in super-Earths in evolving ... · #55 Formation of close-in super-Earths in evolving protoplanetary disks via disk winds Masahiro Ogihara1, Eiichiro Kokubo1,
Post on 06-Jun-2020
3 Views
Preview:
Transcript
#55 Formation of close-in super-Earths in evolving protoplanetary disks via disk windsMasahiro Ogihara1, Eiichiro Kokubo1, Takeru K. Suzuki2, Alessandro Morbidelli3
1 National Astronomical Observatory of Japan, 2 University of Tokyo, 3 Observatoire de la Côte d’Azur
3. Disk evolution 4. In situ formation from embryos in a disk evolving via disk winds(Suzuki, Ogihara, et al. 2016)
5. Resonant chain 6. A limit on gas accretion onto cores 7. Summary
• We focus on the period-ratio distribution of close-in super-Earths (SEs)
• Close-in SEs are generally not in mean-motion resonances (MMRs), which should be reproduced by simulation
❏ Results of N-body simulation • We perform N-body simulations in a power-law disk based on
MMSN• Accretion of SEs is quite rapid in the close-in region because of
high solid surface density• SEs undergo rapid migration in a power-law disk• SEs form in a compact configuration captured in MMRs• The system is stable even after gas depletion• Period-ratio distribution is not matched to observed distribution
@⌃
@t=
1
r
@
@r
⇢2
r⌦
@
@r(r2⌃↵c2s ) + r
2↵w
⌃p⇡H
c2s
��+ Cw
⌃p⇡H
cs
• Magnetically driven disk winds are observed in 3D-MHD simulations
(e.g., Suzuki & Inutsuka 2009, Fromang et al. 2013)
• Disk winds cause wind mass loss and wind-driven accretion
• Suzuki et al. (2016) derived global viscous disk evolution including disk winds by solving the diffusion equation
• Disk profiles can be altered from the power-law disk
❏ Results of N-body simulation • We perform N-body simulations from embryos in disk evolving via disk winds• Type I migration is significantly suppressed owing to small gas density and flat slope in the close-in region• No pileup near the disk inner edge is observed• Planets are captured in MMRs before the disk depletion, which is destroyed by the late orbital instability• Final orbits are not in MMRs, which is consistent with observed period-ratio distribution
• Some systems do not undergo late orbital instability
• Resonant chain can also form
• SE cores should undergo runaway gas accretion based on evolution models of a planetary atmosphere (e.g., Ikoma & Hori 2012)
• We propose that rapid radial accretion near the surface due to wind-driven accretion slips out of the core and regulates the gas supply onto the core
• Planets undergo rapid inward migration in a power-law disk
• Type I migration can be suppressed in a disk evolving via disk winds
• Close-in SEs form in a non-resonant configuration after late orbital instability
• Observed period-ratio distribution can be reproduced
• The gas accretion onto cores can be limited depending on the vertical structure of the radial gas accretion
(Ogihara et al. 2018)
Schematic picture of disk evolution
MHD simulation by Suzuki & Inutsuka (2009)
Evolution of gas surface density
Comparison of period-ratio distribution
Examples of systems with MMRs
Comparison of period-ratio distribution
0.01 0.1 1 10
103
100
10
1
0.1
Semi-Major Axis [Astronomical Units (AU)]
Plan
et M
ass
[Ear
th M
ass]
exoplanets.org | 6/27/2018
0 5
10 15 20 25 30
Num
ber
Period ratio (Pout/Pin) of adjacent pair
2:13:24:35:46:5
7:6
1 102 3 5
0 0.2 0.4 0.6 0.8
1
1 10
Cum
ulativ
e dis
tribu
tion
2:13:24:35:46:5
7:6
2 3 5Period ratio (Pout/Pin) of adjacent pair
0.1
1
103 104 105 106 107 108
Sem
imajo
r axis
(au)
Time (yr)
-2
-1.5
-1
-0.5
0
0.5
1
log(M/M
⊕)
5
0 0.2 0.4 0.6 0.8
1
1 10
Cum
ulativ
e dis
tribu
tion
2:13:24:35:46:5
7:6
2 3 5Period ratio (Pout/Pin) of adjacent pair
10-3
10-2
10-1 1000 yr
0.1 Myr
1 Myr
0.1 1
10 Myr
0.05
Radial distance (au)
Ecce
ntric
ity
Gas surface density (g cm-2)
103
104
105
10-3
10-2
10-1
103
104
105
10-3
10-2
10-1
103
104
105
10-3
10-2
10-1
103
104
105
Radial distance (au)
Ecce
ntric
ity
Gas surface density (g cm-2)
100 Myr
1 Myr
100 yr10-3
10-2
10-1
10-210-1100101102103104105
10-3
10-2
10-1
10-210-1100101102103104105
10-3
10-2
10-1
0.1 110-210-1100101102103104105
viscousaccretion
wind-driven accretion
viscousaccretion
wind-driven accretion
wind mass loss
wind mass loss
10-210-1100101102103104105
0.01 0.1 1 10 100Gas s
urfa
ce d
ensit
y (g
cm-2
)
Radial distance (au)
initial
10-210-1100101102103104105
0.01 0.1 1 10 100Gas s
urfa
ce d
ensit
y (g
cm-2
)
Radial distance (au)
initial1Myr
10-210-1100101102103104105
0.01 0.1 1 10 100Gas s
urfa
ce d
ensit
y (g
cm-2
)
Radial distance (au)
initial1Myr
10Myr
10-210-1100101102103104105
0.01 0.1 1 10 100Gas s
urfa
ce d
ensit
y (g
cm-2
)
Radial distance (au)
initial1Myr
10Myr
10-210-1100101102103104105
0.01 0.1 1 10 100Gas s
urfa
ce d
ensit
y (g
cm-2
)
Radial distance (au)
initial1Myr
10Myr
10-210-1100101102103104105
0.01 0.1 1 10 100Gas s
urfa
ce d
ensit
y (g
cm-2
)
Radial distance (au)
initial1Myr
10Myr
10-210-1100101102103104105
0.01 0.1 1 10 100Gas s
urfa
ce d
ensit
y (g
cm-2
)
Radial distance (au)
initial1Myr
10Myr
10-210-1100101102103104105
0.01 0.1 1 10 100Gas s
urfa
ce d
ensit
y (g
cm-2
)
Radial distance (au)
initial1Myr
10Myr
10-210-1100101102103104105
0.01 0.1 1 10 100Gas s
urfa
ce d
ensit
y (g
cm-2
)
Radial distance (au)
initial1Myr
10Myr
10-210-1100101102103104105
0.01 0.1 1 10 100Gas s
urfa
ce d
ensit
y (g
cm-2
)
Radial distance (au)
initial1Myr
10Myr
10-210-1100101102103104105
0.01 0.1 1 10 100Gas s
urfa
ce d
ensit
y (g
cm-2
)
Radial distance (au)
initial1Myr
10Myr
10-210-1100101102103104105
0.01 0.1 1 10 100Gas s
urfa
ce d
ensit
y (g
cm-2
)
Radial distance (au)
initial1Myr
10Myr
1.60 1.67 1.50(3:2)1.50(3:2)1.34(4:3)
1.25(5:4)1.33(4:3)
1.33(4:3) 1.50(3:2)1.33(4:3)
1.67 3:2 3:2 3:2
4:3 3:2 4:3 5:4
observation
simulation
1 10P/Pinnermost
TRAPPIST-1
Kepler-60
Kepler-223
model5-1
model6-1
model6-2
4:3 7:6
3:2 5:4 5:4 7:65:4 4:3
rz
Rapid gas flow due to wind-driven accretionmay slips out of the core
close-in super-Earths
rapid migration
MMRs stable after gas depletion
observation
10 runs of simulation
MMSN
late orbital instability
late orbital instability
results with Mtotal = 80 M⊕
results with Mtotal = 40 M⊕
results with Mtotal = 20 M⊕
blended results of 3 sets of simulations
1. Close-in super-Earths 2. In situ formation in a power-law disk (Ogihara, Morbidelli, Guillot 2015)
top related