Giant planets around young M-dwarfs › ~dmawet › meetings › mdwarfs.pdfJupiter. Giant Planet...
Transcript of Giant planets around young M-dwarfs › ~dmawet › meetings › mdwarfs.pdfJupiter. Giant Planet...
Giant planets around young M-dwarfs
Henry Ngo (Caltech)
D Mawet, B Bowler, J Wang, O Absil, M Bottom, E Choquet, C Gomez, E Huby, L Hillenbrand,
R Jensen-Clem, T Meshkat, M Reggiani, E Serabyn
Semimajor axis (AU)
Plan
et M
ass
(MJu
p)
Transit Radial Velocity Microlensing
Direct Imaging
Jupiter
Giant Planet Formation
1) Core formation
2) Hydrostatic growth
3) Runaway accretion
4) Planet contracts
Source of gas is removed
Core reaches ~10 Earth masses
Core mass ≈ envelope mass
(and emits energy we can detect)
Challenges • Gather enough solids for critical mass • Reach critical mass before gas dissipates
1) Core formation
2) Hydrostatic growth
3) Runaway accretion
4) Planet contracts
Source of gas is removed
Core reaches ~10 Earth masses
Core mass ≈ envelope mass
Batygin et al. (2016)
Enough solids? Minimum Mass Extrasolar Nebula Chiang & Laughlin (2013) Efficient enough? Compact multi-planet systems Boley et al. (2016) Batygin et al. (2016)
in situ formation
formation then migration
Enough solids? Increase in solids at ice line Lin et al. (1996) Efficient enough? “Pebble accretion” Lambrechts & Johansen (2012)
Predictions • in situ formation: additional smaller planets, P < 100 d
• ice line formation & migration: planet reservoir?
iceline(severalAU)
Young planets Old planets
(observed today)
Predictions • in situ formation: additional smaller planets, P < 100 d
• ice line formation & migration: planet reservoir?
iceline(severalAU)
Young planets Old planets
(observed today) Q: Does this ice-line planet reservoir exist?
Finding young planets at the ice lines
• Target young moving group members
Bowler (2016): Recent efforts to find low-mass members creates large number of potential direct imaging targets
Knowing age is important
Bowler (2016)
Maximize detection ability
Bowler (2016)
Young stars Nearby stars Smaller stars
= better contrast
Detection Probability Sample of 200 late K / M-dwarf (<d> = 40 pc)
L’ vortex on Keck/NIRC2 (IWA = 80 mas)Expected yield (microlensing): 10 planets
Sample star in beta Pic43 pc, 20 Myr, rmag ~9.5
Science image, flattened ADI+PCA processed
(VIP; Gomez Gonzalez et al. 2016)
~ 3”
Sample star in beta Pic43 pc, 20 Myr, rmag ~9.5
5x10-4 contrast @ 0.5”3 MJ @ 22 AU
2x10-3 contrast @ 0.3”6 MJ @ 13 AU
Expect improved contrast down to ~ 0.1” with RDI correction
Progress (since Oct 2015) Schedule
Planned:
4 semesters
Completed: 2 semesters
Next semester (2016B) already
allocated.
Apply for final semester (2017A)
next month
Summary • Two hot Jupiter formation models – in situ: predicts additional small planets with
periods < 100 days – migration: predicts reservoir of young planets
near ice line • Survey of ~200 M-dwarfs in L-band on
Keck/NIRC2 with vortex to confirm or refute ice line planet reservoir
• Reggiani/Absil: Southern survey on VLT