KOI-730

KOI-730 as a System of Four Planets in a Chain of Resonances Daniel Fabrycky UC Santa Cruz Matthew Holman, Joshua Carter, Jason Rowe, Darin Ragozzine, William Borucki, David Koch, and the Kepler Team

Planets in Resonance • Resonances are common among RV-discovered gas giants (~1 period commensurability in 3 multi systems: Wright et al. 2011, a 4:2:1 chain in GJ 876: Rivera et al. 2010)

• Kepler has found Neptune-size pairs especially abundant near resonances (Lissauer et al. 2011) • Theories suggest the Solar System giants may have started in a resonant chain (Morbidelli et al. 2007, Thommes et al. 2008)

KOI-730: Three Pairs of First-Order Resonances candidate period (d) Rp (RE) 730.04

7.3831

1.8

730.02

9.8499

2.1

730.01

14.7903

2.8

730.02

19.7216

2.4

P/P=1.33411(8)

4:3

P/P=1.50157(5)

3:2

P/P=1.33341(3)

4:3

3:4:6:8

Laplace-type resonances • Involves 3 planets at once • Io, Europa, & Gaynmede obey λI-3λE+2λG=180°

TTVs??

P=7.3831 d dP/dE= -1±1 s

P=9.8499 d dP/dE= 0±3 s Observed: transit times through Q8

P=14.7903 d dP/dE= 15±2 s

P=19.7216 d dP/dE= -12±12 s

Theory: • Match P, T0 • coplanar • mass: Mp = Rp2.06 •e=0 relax

Disk Migration Theory Lee & Peale 02 GJ 876 b/c

Rules-of-thumb for resonance capture: • Converging and slow • Low eccentricity favors first-order resonances • High eccentricity favors high-order resonances

Capture into Resonance  first-order resonances  Laplace-type resonances  moderate eccentricities  increased stability

KOI-730: • A candidate system of 4 low-mass planets on compact, resonant orbits • It informs migration models: limits the speed, direction, and damping properties • It’s the missing link to RV exoplanet systems, the Kepler multis, and maybe even the Solar System giants

Coorbital no more

KOI-730.03’s period was revised from 9.861 days to twice that: 19.722 days. This took it out of 1:1 resonance with KOI730.02. This was apparent even in the Q1-Q2 data and is confirmed by the data through Q8.

• Stellar properties (determined by photometry, accounting for a blended companion, and fit to isochrones): Kp 15.3 mag