A Caltech Library Service

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

Wang, Songhu and Addison, Brett and Fischer, Debra A. and Brewer, John M. and Isaacson, Howard and Howard, Andrew W. and Laughlin, Gregory (2018) Stellar Spin–Orbit Alignment for Kepler-9, a Multi-transiting Planetary System with Two Outer Planets Near 2:1 Resonance. Astronomical Journal, 155 (2). Art. No. 70. ISSN 1538-3881.

[img] PDF - Published Version
See Usage Policy.

[img] PDF - Submitted Version
See Usage Policy.


Use this Persistent URL to link to this item:


We present spectroscopic measurements of the Rossiter–McLaughlin effect for the planet b of the Kepler-9 multi-transiting planetary system. The resulting sky-projected spin–orbit angle is λ = −13° ± 16°, which favors an aligned system and strongly disfavors highly misaligned, polar, and retrograde orbits. Including Kepler-9, there are now a total of four Rossiter–McLaughlin effect measurements for multiplanet systems, all of which are consistent with spin–orbit alignment.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Wang, Songhu0000-0002-7846-6981
Addison, Brett0000-0003-3216-0626
Fischer, Debra A.0000-0003-2221-0861
Brewer, John M.0000-0002-9873-1471
Isaacson, Howard0000-0002-0531-1073
Howard, Andrew W.0000-0001-8638-0320
Laughlin, Gregory0000-0002-3253-2621
Additional Information:© 2018. The American Astronomical Society. Received 2017 September 22; revised 2017 December 7; accepted 2017 December 17; published 2018 January 19. We are thankful to the referee Simon Albrecht for providing a thorough review that greatly improved the manuscript. We would also like to thank Dong Lai, Amaury Triaud, Christopher Spalding, Smadar Naoz, Douglas Lin, Yasunori Hori, and Hui-Gen Liu for useful discussions, as well as Yutong Wu, Xiaojia Zhang, and Dong-Hong Wu for improving the quality of the figures. S.W. acknowledges the Heising-Simons Foundation for their generous support. Finally, the authors wish to recognize and acknowledge the very significant cultural role and reverence that the summit of Mauna Kea has always had within the indigenous Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this mountain.
Group:Astronomy Department
Funding AgencyGrant Number
Heising-Simons FoundationUNSPECIFIED
Subject Keywords:methods: observational; planetary systems; planets and satellites: individual (Kepler-9b) ; stars: individual (Kepler-9) ; techniques: radial velocities; techniques: spectroscopic
Issue or Number:2
Record Number:CaltechAUTHORS:20180118-145948077
Persistent URL:
Official Citation:Songhu Wang et al 2018 AJ 155 70
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:84398
Deposited By: George Porter
Deposited On:19 Jan 2018 15:26
Last Modified:09 Mar 2020 13:19

Repository Staff Only: item control page