Stellar Spin-Orbit Alignment for Kepler-9, a Multi-transiting Planetary system with Two Outer Planets Near 2:1 Resonance

Abstract

We present spectroscopic measurements of the Rossiter-McLaughlin effect for the planet b of Kepler-9 multi-transiting planet system. The resulting sky-projected spin-orbit angle is $\lambda =-13^{\circ }\pm 16^{\circ }$, which favors an aligned system and strongly disfavors highly misaligned, polar, and retrograde orbits. Including Kepler-9, there are now a total of 4 Rossiter-McLaughlin effect measurements for multiplanet systems, all of which are consistent with spin-orbit alignment.

Accepted for publication in the Astronomical Journal

References in corpus (13)

• Formation of Hot Planets by a combination of planet scattering, tidal circularization, and Kozai mechanism
• Origins of Eccentric Extrasolar Planets: Testing the Planet-Planet Scattering Model
• Alignment of the stellar spin with the orbits of a three-planet system
• Photometric Amplitude Distribution of Stellar Rotation of Kepler KOIs-Indication for Spin-Orbit Alignment of Cool Stars and High Obliquity for Hot Stars
• Obliquities of Kepler Stars: Comparison of Single- and Multiple-Transit Systems
• The Turbulent Origin of Spin-Orbit Misalignment in Planetary Systems
• Determination of Three-dimensional Spin-orbit Angle with Joint Analysis of Asteroseismology, Transit Lightcurve, and the Rossiter-McLaughlin Effect: Cases of HAT-P-7 and Kepler-25
• Chaotic Dynamics of Stellar Spin in Binaries and the Production of Misaligned Hot Jupiters
• On the tidal origin of hot Jupiter stellar obliquity trends
• Accurate Gravities of F, G, and K stars from High Resolution Spectra Without External Constraints
• Time variation of Kepler transits induced by stellar rotating spots - a way to distinguish between prograde and retrograde motion I. Theory
• A Spin-Orbit Alignment for the Hot Jupiter HATS-3b
• The well-aligned orbit of WASP-84b: evidence for disc migration

Cited by in corpus (4)

• Kepler-730: A hot Jupiter system with a close-in, transiting, Earth-sized planet
• HARPS-N radial velocities confirm the low densities of the Kepler-9 planets
• Truly eccentric. I. Revisiting eight single-eccentric planetary systems
• Transiting Exoplanet Monitoring Project (TEMP). II. Refined System Parameters and Transit Timing Analysis of HAT-P-33b