Circumbinary Planets/Disks

Transcription

1 Circumbinary Planets/Disks Dong Lai Cornell University -- Simula6ons of circumbinary accre6on: Eccentric Disks, Ang. Mom. Transfer Diego Munoz & DL 2016 Ryan Miranda, Munoz, DL Misaligned circumbinary planets around compact (<5 day) binaries. Munoz & DL Destruc6on of circumbinary planets by evec6on resonance Wenrui Xu & DL /6/2016, Exoplanets I, Davos

2 Hiding Planets Behind a Big Friend Multi-Planet System with an External Companion Dong Lai & Bonan Pu Cornell University arxiv: Exoplanets I Conference, Davos, July 6, 2016

3 Kepler: 4700 planets in 3600 systems (mostly super-earth or sub-neptunes, <200 days) (5/17/2016) Observed Transit MulGplicity DistribuGon F (N tran ) Number of systems Number of TransiGng planets

4 F (N tran ) ===> the underlying mulgplicity distribugon & mutual inclinagons Degeneracy can be broken by RV data (Tremaine & Dong 12) Transit dura6on ra6o (Fabrycky+14) Kepler compact systems are flat, with mutual inclinagon dispersion < 2 degrees Lissauer+11, Tremaine & Dong 12, Figueira+12, Fabrycky+14; Fang & Margot 12

5 Models with single inclinagon dispersion (e.g. in Rayleigh) do not fit well: Under-predict Kepler singles by a factor of > 2 Lissauer+11, Johansen, Davies +12, Weissbein+12, Ballard & Johnson+16 Number of systems Red: best-fit to mu6ple-transit planet systems with single Inclina6on dispersion Number of TransiGng planets

6 Kepler Dichotomy Kepler systems consist of at least two underlying populagons: (1) Systems N > ~6 planets with small mutual inclina6ons (~2 degrees): Account for most of Kepler Mul6 s (N tran >1) (2) Systems with fewer planets or with higher mutual inclina6ons: Account for a (large) frac6on Kepler singles (N tran =1)

7 Kepler Dichotomy Kepler systems consist of at least two underlying populagons: (1) Systems N > ~6 planets with small mutual inclina6ons (~2 degrees): Account for most of Kepler Mul6 s (N tran >1) (2) Systems with fewer planets or with higher mutual inclina6ons: Account for a large frac6on Kepler singles (N tran =1) Other evidence that (some) Kepler singles are special : (1) singles have higher stellar obliqui6es (Morton & Winn 14) (2) Mul6 s have more detectable TTVs than singles (Xie, Wu & Lithwick 14) (3) 10-30% of singles have higher e s (Jiwei Xie s poster) (4) Single Hot Earth excess (Jason Staffen s talk)

8 Origin of Kepler Dichotomy -- Primordial in-situ assembly of planetesimal disks with different mass & density profile (Mariarty & Ballard 15) -- Dynamical instability 6ghtly packed system! unstable! collision/consolida6on (Volk & Gladman 15; Pu & Wu 15) -- External Perturber (Giant planet or companion star)

9 Two-planet system with an external inclined perturber m 1, m 2 ini6ally co-planar m 1 m 2 p m p companion star or cold Jupiter (e.g. produced by planet-planet scaperings)

10 m 1 p L 1 Lp m p Precession of 1 driven by p : 1p m p M? a1 3 n 1 / m p a p a 3 p a 3/2 1

11 m 1 m 2! 12! 21 1p 2p m p Mutual inclina6on induced by perturber depends on Coupling Parameter

12

13 Maximum Mutual InclinaGon Induced by external perturber p = 10 / m p a 3 p

14 Resonance Feature: 12 1 exists when m 2 & m 1 Nodal Precession Resonance m 1 m 2! 12 1p 2p m p In the m 2 m 1 limit: Resonance occurs at 2p = 1p +! 12 or 12 =1

15 Resonance Feature: 12 1 Can produce much larger mutual inclination than p

16 Resonance Feature: 12 1 Can produce much larger mutual inclination than p

17 MulG-planet system with an external inclined perturber m 1 m 2 m 3 m 4 p m p

18 4 planet system with an external perturber dispersion of mutual inclination averaged coupling parameter / m p /a 3 p

19 4 planet system with an external perturber dispersion of mutual inclination averaged coupling parameter / m p /a 3 p

20 Recap: An understanding and semi-analygc expression for the mutual inclina6on of mul6-planets induced by distant perturber m 1 m 2 p 1p 12 = 2p! 12 +! 21 3 mp a2 m p m 2 a p for m 2 m 1, a 2 1.5a 1 e.g., for m 2 m at a au 1M J perturber at 3 au gives For 12 & 2: For : 12 2 p sin 2 p

21 ApplicaGon: Evaluate /constrain external perturber of observed systems Examples: (see DL & Pu for more) Kepler-68: Two super-earths at 0.06,0.09 au, 1 M J planet at 1.4 au is weak Kepler-56: WASP-47:... Kepler-48: Three transi6ng planets (0.012,0.046,0.015M J ) at 0.053,0.085,0.23 au, >2M J companion (Kepler-48e) at 1.85 au (Marcy+14) " Kepler-48e must be aligned <2 degree Kepler-454: one super-earth at 0.1 au with a >5M J at 524 days (Gepel+16) " any neighbor to the inner planet could be strongly misaligned by the giant (This could of mul6-planet system that has been turned into Kepler single by an external giant planet) I am happy to receive about other systems (star or giant planet perturbers)

22 What about Kepler Dichotomy? A significant frac6on of Kepler singles (N tran =1) are/were mul6-planet systems that have been misaligned (in mutual inclina6ons) or disrupted by external perturbers (cold giant planets or stellar companions) Cold Giant Planets: Some have been found, but general census not clear? (50% of HJs/WJs have 1-20M J companion at 5-20 au; Bryan et al 2016) Stellar Companions: J.Wang et al (2015): ~5% of Kepler mul6s have stellar companion au (4x lower than field stars) More studies are needed.

23 General Comment: Influences of External Perturbers on (Inner) Planetary Systems --- Mutual inclina6ons (DL & Pu 2016) --- Forma6on of Hot Jupiters and Warm Jupiters (high-e migra6on) (many papers ) e.g. High-e migra6on induced by stellar companion contrinutes ~10-15% of HJs (Petrovich 15; Anderson, Storch & DL 16; Munoz, DL+16) --- Evec6on resonance (Touma & Sridhar 15; Xu & DL 16)