constraining the initial entropy of directly-detected exoplanets · 2012. 9. 7. · motivation...
TRANSCRIPT
Motivation Inferring M and Si from L and age Conclusion
Constraining the initial entropy of directly-detected exoplanets
Gabriel-Dominique Marleau1,2 Andrew Cumming2
1 MPIA (Heidelberg) 2 McGill University (Canada)
Skemer et al. (2012) Currie et al. (2011)
Motivation Inferring M and Si from L and age Conclusion
Overview
1 MotivationDirect detection surveysUncertainty in post-formation conditions
2 Inferring M and Si from L and ageCooling modelsApplications
3 Conclusion
Constraining the initial entropy of directly-detected exoplanets 1 / 13 Marleau & Cumming
Motivation Inferring M and Si from L and age Conclusion
Overview
1 MotivationDirect detection surveysUncertainty in post-formation conditions
2 Inferring M and Si from L and ageCooling modelsApplications
3 Conclusion
Constraining the initial entropy of directly-detected exoplanets 2 / 13 Marleau & Cumming
Motivation Inferring M and Si from L and age Conclusion
Direct detection surveys
Direct imaging
Bias towards young, massive, and hot planets
Many surveys on now or soon: SPHERE, GPI, VLT, HiCIAO, JWST, etc.
→ Dramatic increase in number and detection of core-accretion candidates
Dominik (2011), modif.
106 107 108 109 1010
Age (yr)
10-7
10-6
10-5
10-4
10-3
10-2
Lum
inosity (
LS
un)
Neuhäuser & Schmidt (2012)
Constraining the initial entropy of directly-detected exoplanets 3 / 13 Marleau & Cumming
Motivation Inferring M and Si from L and age Conclusion
Direct detection surveys
Direct imaging
Bias towards young, massive, and hot planets
Many surveys on now or soon: SPHERE, GPI, VLT, HiCIAO, JWST, etc.
→ Dramatic increase in number and detection of core-accretion candidates
Dominik (2011), modif.
106 107 108 109 1010
Age (yr)
10-7
10-6
10-5
10-4
10-3
10-2
Lum
inosity (
LS
un)
Neuhäuser & Schmidt (2012)
Constraining the initial entropy of directly-detected exoplanets 3 / 13 Marleau & Cumming
Motivation Inferring M and Si from L and age Conclusion
Uncertainty in post-formation conditions
Hot start or cold start?
Core accretion: closer-in, less massive, colder (lower S)
Gravitational instability: tens of AU, heavier, hotter
? Actually, uncertain initial conditions →
Marley et al. (2007)
Spiegel & Burrows (2012)
Constraining the initial entropy of directly-detected exoplanets 4 / 13 Marleau & Cumming
Motivation Inferring M and Si from L and age Conclusion
Uncertainty in post-formation conditions
Hot start or cold start?
Core accretion: closer-in, less massive, colder (lower S)
Gravitational instability: tens of AU, heavier, hotter
? Actually, uncertain initial conditions → need to consider arbitrary Si
Marley et al. (2007)
Spiegel & Burrows (2012)
Constraining the initial entropy of directly-detected exoplanets 4 / 13 Marleau & Cumming
Motivation Inferring M and Si from L and age Conclusion
Uncertainty in post-formation conditions
Hot start or cold start?
Core accretion: closer-in, less massive, colder (lower S)
Gravitational instability: tens of AU, heavier, hotter
? Actually, uncertain initial conditions → need to consider arbitrary Si
Marley et al. (2007)Spiegel & Burrows (2012)
Constraining the initial entropy of directly-detected exoplanets 4 / 13 Marleau & Cumming
Motivation Inferring M and Si from L and age Conclusion
Uncertainty in post-formation conditions
Consequences
Hot-start models used for planning → overpredict yields
Masses assigned from hot starts → wrong statistics
Conversely: use detections to inform formation scenarios
Constraining the mass and initial entropy of directly-detected planets
Make planet models with arbitrary entropy → L(M,S(t))
Given L and age, find which (M,Si) correspond to this
? Independent of formation model!
Constraining the initial entropy of directly-detected exoplanets 5 / 13 Marleau & Cumming
Motivation Inferring M and Si from L and age Conclusion
Uncertainty in post-formation conditions
Consequences
Hot-start models used for planning → overpredict yields
Masses assigned from hot starts → wrong statistics
Conversely: use detections to inform formation scenarios
Constraining the mass and initial entropy of directly-detected planets
Make planet models with arbitrary entropy → L(M,S(t))
Given L and age, find which (M,Si) correspond to this
? Independent of formation model!
Constraining the initial entropy of directly-detected exoplanets 5 / 13 Marleau & Cumming
Motivation Inferring M and Si from L and age Conclusion
Uncertainty in post-formation conditions
Consequences
Hot-start models used for planning → overpredict yields
Masses assigned from hot starts → wrong statistics
Conversely: use detections to inform formation scenarios
Constraining the mass and initial entropy of directly-detected planets
Make planet models with arbitrary entropy → L(M,S(t))
Given L and age, find which (M,Si) correspond to this
? Independent of formation model!
Constraining the initial entropy of directly-detected exoplanets 5 / 13 Marleau & Cumming
Motivation Inferring M and Si from L and age Conclusion
Uncertainty in post-formation conditions
Consequences
Hot-start models used for planning → overpredict yields
Masses assigned from hot starts → wrong statistics
Conversely: use detections to inform formation scenarios
Constraining the mass and initial entropy of directly-detected planets
Make planet models with arbitrary entropy → L(M,S(t))
Given L and age, find which (M,Si) correspond to this
? Independent of formation model!
Constraining the initial entropy of directly-detected exoplanets 5 / 13 Marleau & Cumming
Motivation Inferring M and Si from L and age Conclusion
Overview
1 MotivationDirect detection surveysUncertainty in post-formation conditions
2 Inferring M and Si from L and ageCooling modelsApplications
3 Conclusion
Constraining the initial entropy of directly-detected exoplanets 6 / 13 Marleau & Cumming
Motivation Inferring M and Si from L and age Conclusion
Cooling models
Thermal evolution of gas giant planets
Standard opacities and composition
Usual constant-S structure equations
Given M and S → Lbol and tcool
(Found Lbol(M,S)) explanable)
→ Grid of models specified by M and S
7 8 9 10 11 12 13 14Entropy (kB/baryon)
10-8
10-6
10-4
10-2
L,
LD (
LS
un)
10 MJ
15 MJ
20 MJ
at t=0
at t=0
at t=0
20 MJ
15 MJ
10 MJ
3 MJ
1 MJ
100 102 104 106 108
Pressure (bar)
103
104
105
Te
mp
era
ture
(K
)
time
Si
Si-∆S
Marleau & Cumming 2012 (in prep.)
Constraining the initial entropy of directly-detected exoplanets 7 / 13 Marleau & Cumming
Motivation Inferring M and Si from L and age Conclusion
Cooling models
Thermal evolution of gas giant planets
Standard opacities and composition
Usual constant-S structure equations
Given M and S → Lbol and tcool
(Found Lbol(M,S)) explanable)
→ Grid of models specified by M and S
7 8 9 10 11 12 13 14Entropy (kB/baryon)
10-8
10-6
10-4
10-2
L,
LD (
LS
un)
10 MJ
15 MJ
20 MJ
at t=0
at t=0
at t=0
20 MJ
15 MJ
10 MJ
3 MJ
1 MJ
100 102 104 106 108
Pressure (bar)
103
104
105
Te
mp
era
ture
(K
)
time
Si
Si-∆S
Marleau & Cumming 2012 (in prep.)
Constraining the initial entropy of directly-detected exoplanets 7 / 13 Marleau & Cumming
Motivation Inferring M and Si from L and age Conclusion
Cooling models
Thermal evolution of gas giant planets
Standard opacities and composition
Usual constant-S structure equations
Given M and S → Lbol and tcool
(Found Lbol(M,S)) explanable)
→ Grid of models specified by M and S
7 8 9 10 11 12 13 14Entropy (kB/baryon)
10-8
10-6
10-4
10-2
L,
LD (
LS
un)
10 MJ
15 MJ
20 MJ
at t=0
at t=0
at t=0
20 MJ
15 MJ
10 MJ
3 MJ
1 MJ
100 102 104 106 108
Pressure (bar)
103
104
105
Te
mp
era
ture
(K
)
time
Si
Si-∆S
Marleau & Cumming 2012 (in prep.)
Constraining the initial entropy of directly-detected exoplanets 7 / 13 Marleau & Cumming
Motivation Inferring M and Si from L and age Conclusion
Cooling models
Thermal evolution of gas giant planets (cont’d)
Cooling curves:
! Low S means long tcool
t < tcool: ≈ remember i.c.
t > tcool: ≈ power law
106 107 108 109
Age (yr)
10-8
10-7
10-6
10-5
10-4
10-3
10-2
Lum
inosity (
LS
un)
10 MJ
3 MJ
1 MJ
Si = 8
Si = 9
Si = 12
Marleau & Cumming 2012 (in prep.)
Neuhäuser & Schmidt (2012)
Constraining the initial entropy of directly-detected exoplanets 8 / 13 Marleau & Cumming
Motivation Inferring M and Si from L and age Conclusion
Cooling models
Thermal evolution of gas giant planets (cont’d)
Cooling curves:
! Low S means long tcool
t < tcool: ≈ remember i.c.
t > tcool: ≈ power law
106 107 108 109
Age (yr)
10-8
10-7
10-6
10-5
10-4
10-3
10-2
Lum
inosity (
LS
un)
10 MJ
3 MJ
1 MJ
Si = 8
Si = 9
Si = 12
Marleau & Cumming 2012 (in prep.)
Neuhäuser & Schmidt (2012)
Constraining the initial entropy of directly-detected exoplanets 8 / 13 Marleau & Cumming
Motivation Inferring M and Si from L and age Conclusion
Cooling models
Thermal evolution of gas giant planets (cont’d)
Cooling curves:
! Low S means long tcool
t < tcool: ≈ remember i.c.
t > tcool: ≈ power law
106 107 108 109
Age (yr)
10-8
10-7
10-6
10-5
10-4
10-3
10-2
Lum
inosity (
LS
un)
10 MJ
3 MJ
1 MJ
Si = 8
Si = 9
Si = 12
Marleau & Cumming 2012 (in prep.)
Neuhäuser & Schmidt (2012)
Constraining the initial entropy of directly-detected exoplanets 8 / 13 Marleau & Cumming
Motivation Inferring M and Si from L and age Conclusion
Cooling models
Thermal evolution of gas giant planets (cont’d)
Cooling curves:
! Low S means long tcool
t < tcool: ≈ remember i.c.
t > tcool: ≈ power law
106 107 108 109
Age (yr)
10-8
10-7
10-6
10-5
10-4
10-3
10-2
Lum
inosity (
LS
un)
10 MJ
3 MJ
1 MJ
Marleau & Cumming 2012 (in prep.)Neuhäuser & Schmidt (2012)
Constraining the initial entropy of directly-detected exoplanets 8 / 13 Marleau & Cumming
Motivation Inferring M and Si from L and age Conclusion
Applications
HR 8799 b
Marois et al., Zuckerman (2010)
Hot-start masses
Multiple system → dynamical info
→ Lower bound on Si
CA too cold by ∆S = 0.5 but ok
106 107 108 109
Age (yr)
10-7
10-6
10-5
10-4
10-3
10-2
Lu
min
osity (
LS
un)
0 2 4 6 8 10Mass (MJ)
7
8
9
10
11
12
Initia
l e
ntr
op
y
0 2 4 6 8 10
30 Myr60 Myr30 Myr60 Myr
Marleau & Cumming 2012 (in prep.)
Constraining the initial entropy of directly-detected exoplanets 9 / 13 Marleau & Cumming
Motivation Inferring M and Si from L and age Conclusion
Applications
HR 8799 b
Marois et al., Zuckerman (2010)
Hot-start masses
Multiple system → dynamical info
→ Lower bound on Si
CA too cold by ∆S = 0.5 but ok
106 107 108 109
Age (yr)
10-7
10-6
10-5
10-4
10-3
10-2
Lu
min
osity (
LS
un)
8.1 MJ, high Si
0 2 4 6 8 10Mass (MJ)
7
8
9
10
11
12
Initia
l e
ntr
op
y
0 2 4 6 8 10
30 Myr60 Myr30 Myr60 Myr
Constraining the initial entropy of directly-detected exoplanets 9 / 13 Marleau & Cumming
Motivation Inferring M and Si from L and age Conclusion
Applications
HR 8799 b
Marois et al., Zuckerman (2010)
Hot-start masses
Multiple system → dynamical info
→ Lower bound on Si
CA too cold by ∆S = 0.5 but ok
106 107 108 109
Age (yr)
10-7
10-6
10-5
10-4
10-3
10-2
Lu
min
osity (
LS
un)
8.1 MJ, high Si
10.5 MJ, Si = 9.3
0 2 4 6 8 10Mass (MJ)
7
8
9
10
11
12
Initia
l e
ntr
op
y
0 2 4 6 8 10
30 Myr60 Myr30 Myr60 Myr
Constraining the initial entropy of directly-detected exoplanets 9 / 13 Marleau & Cumming
Motivation Inferring M and Si from L and age Conclusion
Applications
HR 8799 b
Marois et al., Zuckerman (2010)
Hot-start masses
Multiple system → dynamical info
→ Lower bound on Si
CA too cold by ∆S = 0.5 but ok
106 107 108 109
Age (yr)
10-7
10-6
10-5
10-4
10-3
10-2
Lu
min
osity (
LS
un)
8.1 MJ, high Si
10.5 MJ, Si = 9.3
0 2 4 6 8 10Mass (MJ)
7
8
9
10
11
12
Initia
l e
ntr
op
y
0 2 4 6 8 10
30 Myr60 Myr30 Myr60 Myr
Constraining the initial entropy of directly-detected exoplanets 9 / 13 Marleau & Cumming
Motivation Inferring M and Si from L and age Conclusion
Applications
HR 8799 b
Marois et al., Zuckerman (2010)
Hot-start masses
Multiple system → dynamical info
→ Lower bound on Si
CA too cold by ∆S = 0.5 but ok
106 107 108 109
Age (yr)
10-7
10-6
10-5
10-4
10-3
10-2
Lu
min
osity (
LS
un)
8.1 MJ, high Si
10.5 MJ, Si = 9.3
0 2 4 6 8 10Mass (MJ)
7
8
9
10
11
12
Initia
l e
ntr
op
y
0 2 4 6 8 10
30 Myr60 Myr30 Myr60 Myr
Constraining the initial entropy of directly-detected exoplanets 9 / 13 Marleau & Cumming
Motivation Inferring M and Si from L and age Conclusion
Applications
β Pic
Lagrange et al. (2011)
Upper mass from RV → minimum Si
Traditional CA too cold by ∆S = 1.5
(but more realistic shock → ok?)
Assume dN/dM → posterior on Si
4 Myr20 Myr
0 5 10 15 20Mass (MJ)
7
8
9
10
11
12
Initia
l e
ntr
op
yMarleau & Cumming 2012 (in prep.)
Constraining the initial entropy of directly-detected exoplanets 10 / 13 Marleau & Cumming
Motivation Inferring M and Si from L and age Conclusion
Applications
β Pic
Lagrange et al. (2011)
Upper mass from RV → minimum Si
Traditional CA too cold by ∆S = 1.5
(but more realistic shock → ok?)
Assume dN/dM → posterior on Si
4 Myr20 Myr
Excludedby RV
0 5 10 15 20Mass (MJ)
7
8
9
10
11
12
Initia
l e
ntr
op
yMarleau & Cumming 2012 (in prep.)
Constraining the initial entropy of directly-detected exoplanets 10 / 13 Marleau & Cumming
Motivation Inferring M and Si from L and age Conclusion
Applications
β Pic
Lagrange et al. (2011)
Upper mass from RV → minimum Si
Traditional CA too cold by ∆S = 1.5
(but more realistic shock → ok?)
Assume dN/dM → posterior on Si
4 Myr20 Myr
Excludedby RV
0 5 10 15 20Mass (MJ)
7
8
9
10
11
12
Initia
l e
ntr
op
yMarleau & Cumming 2012 (in prep.)
Constraining the initial entropy of directly-detected exoplanets 10 / 13 Marleau & Cumming
Motivation Inferring M and Si from L and age Conclusion
Applications
β Pic
Lagrange et al. (2011)
Upper mass from RV → minimum Si
Traditional CA too cold by ∆S = 1.5(but more realistic shock → ok?)
Assume dN/dM → posterior on Si
4 Myr20 Myr
Excludedby RV
0 5 10 15 20Mass (MJ)
7
8
9
10
11
12
Initia
l e
ntr
op
yMarleau & Cumming 2012 (in prep.)
Constraining the initial entropy of directly-detected exoplanets 10 / 13 Marleau & Cumming
Motivation Inferring M and Si from L and age Conclusion
Applications
β Pic
Lagrange et al. (2011)
Upper mass from RV → minimum Si
Traditional CA too cold by ∆S = 1.5(but more realistic shock → ok?)
Assume dN/dM → posterior on Si
4 Myr20 Myr
With differentN(M) priors
Excludedby RV
0 5 10 15 20Mass (MJ)
7
8
9
10
11
12
Initia
l e
ntr
op
yMarleau & Cumming 2012 (in prep.)
Constraining the initial entropy of directly-detected exoplanets 10 / 13 Marleau & Cumming
Motivation Inferring M and Si from L and age Conclusion
Applications
Complication: Deuterium burning
Add deuterium burning (M & 13 MJ):
Lbol = −dSdt
∫T dm + LD
Cooling slowed down
Gives late-time D flashes
Can realistically be formed?
→ Observational consequences
Detectable by D in spectrum?
106 107 108 109 1010
Time (yr)
10-7
10-6
10-5
10-4
10-3
10-2
L (
LS
un)
Si = 14
Si = 7.5
16 MJ
Marleau & Cumming 2012 (in prep.)
Constraining the initial entropy of directly-detected exoplanets 11 / 13 Marleau & Cumming
Motivation Inferring M and Si from L and age Conclusion
Applications
Complication: Deuterium burning
Add deuterium burning (M & 13 MJ):
Lbol = −dSdt
∫T dm + LD
Cooling slowed down
Gives late-time D flashes
Can realistically be formed?
→ Observational consequences
Detectable by D in spectrum?
106 107 108 109 1010
Time (yr)
10-7
10-6
10-5
10-4
10-3
10-2
L (
LS
un)
Si = 14
Si = 7.5
16 MJ
Marleau & Cumming 2012 (in prep.)
Constraining the initial entropy of directly-detected exoplanets 11 / 13 Marleau & Cumming
Motivation Inferring M and Si from L and age Conclusion
Applications
Complication: Deuterium burning
Add deuterium burning (M & 13 MJ):
Lbol = −dSdt
∫T dm + LD
Cooling slowed down
Gives late-time D flashes
Can realistically be formed?
→ Observational consequences
Detectable by D in spectrum?
106 107 108 109 1010
Time (yr)
10-7
10-6
10-5
10-4
10-3
10-2
L (
LS
un)
Si = 14
Si = 7.5
16 MJ
Marleau & Cumming 2012 (in prep.)
Constraining the initial entropy of directly-detected exoplanets 11 / 13 Marleau & Cumming
Motivation Inferring M and Si from L and age Conclusion
Overview
1 MotivationDirect detection surveysUncertainty in post-formation conditions
2 Inferring M and Si from L and ageCooling modelsApplications
3 Conclusion
Constraining the initial entropy of directly-detected exoplanets 12 / 13 Marleau & Cumming
Motivation Inferring M and Si from L and age Conclusion
Summary and outlook
? Thank you for your attention! ?
Proper interpretation of direct detections → M possibly � M hot start
Key point
Given L at t, can calculate curve of allowed M–Si
Other M information → constrain hot-/coldness of start
→ Statistically compare with formation models (population synthesis)
Application to HR 8799 system and β Pic: their Si > 9.5
→ Need to tweak core accretion to explain β Pic
Exciting future as close-in planets start being detected
Marleau & Cumming (2012) soon on arXiv!
Constraining the initial entropy of directly-detected exoplanets 13 / 13 Marleau & Cumming
Motivation Inferring M and Si from L and age Conclusion
Summary and outlook
? Thank you for your attention! ?
Proper interpretation of direct detections → M possibly � M hot start
Key point
Given L at t, can calculate curve of allowed M–Si
Other M information → constrain hot-/coldness of start
→ Statistically compare with formation models (population synthesis)
Application to HR 8799 system and β Pic: their Si > 9.5
→ Need to tweak core accretion to explain β Pic
Exciting future as close-in planets start being detected
Marleau & Cumming (2012) soon on arXiv!
Constraining the initial entropy of directly-detected exoplanets 13 / 13 Marleau & Cumming
Motivation Inferring M and Si from L and age Conclusion
Summary and outlook
? Thank you for your attention! ?
Proper interpretation of direct detections → M possibly � M hot start
Key point
Given L at t, can calculate curve of allowed M–Si
Other M information → constrain hot-/coldness of start
→ Statistically compare with formation models (population synthesis)
Application to HR 8799 system and β Pic: their Si > 9.5
→ Need to tweak core accretion to explain β Pic
Exciting future as close-in planets start being detected
Marleau & Cumming (2012) soon on arXiv!
Constraining the initial entropy of directly-detected exoplanets 13 / 13 Marleau & Cumming
Motivation Inferring M and Si from L and age Conclusion
Summary and outlook
? Thank you for your attention! ?
Proper interpretation of direct detections → M possibly � M hot start
Key point
Given L at t, can calculate curve of allowed M–Si
Other M information → constrain hot-/coldness of start
→ Statistically compare with formation models (population synthesis)
Application to HR 8799 system and β Pic: their Si > 9.5
→ Need to tweak core accretion to explain β Pic
Exciting future as close-in planets start being detected
Marleau & Cumming (2012) soon on arXiv!
Constraining the initial entropy of directly-detected exoplanets 13 / 13 Marleau & Cumming
Motivation Inferring M and Si from L and age Conclusion
Summary and outlook
? Thank you for your attention! ?
Proper interpretation of direct detections → M possibly � M hot start
Key point
Given L at t, can calculate curve of allowed M–Si
Other M information → constrain hot-/coldness of start
→ Statistically compare with formation models (population synthesis)
Application to HR 8799 system and β Pic: their Si > 9.5
→ Need to tweak core accretion to explain β Pic
Exciting future as close-in planets start being detected
Marleau & Cumming (2012) soon on arXiv!
Constraining the initial entropy of directly-detected exoplanets 13 / 13 Marleau & Cumming
Motivation Inferring M and Si from L and age Conclusion
Summary and outlook
? Thank you for your attention! ?
Proper interpretation of direct detections → M possibly � M hot start
Key point
Given L at t, can calculate curve of allowed M–Si
Other M information → constrain hot-/coldness of start
→ Statistically compare with formation models (population synthesis)
Application to HR 8799 system and β Pic: their Si > 9.5
→ Need to tweak core accretion to explain β Pic
Exciting future as close-in planets start being detected
Marleau & Cumming (2012) soon on arXiv!
Constraining the initial entropy of directly-detected exoplanets 13 / 13 Marleau & Cumming