A Caltech Library Service

Orbital Orientations of Exoplanets: HAT-P-4b is Prograde and HAT-14b is Retrograde

Winn, Joshua N. and Howard, Andrew W. and Johnson, John Asher and Marcy, Geoffrey W. and Isaacson, Howard and Shporer, Avi and Bakos, Gáspár Á. and Hartman, Joel D. and Holman, Matthew J. and Albrecht, Simon and Crepp, Justin R. and Morton, Timothy D. (2011) Orbital Orientations of Exoplanets: HAT-P-4b is Prograde and HAT-14b is Retrograde. Astronomical Journal, 141 (2). Art. No. 63. ISSN 0004-6256.

PDF - Published Version
See Usage Policy.


Use this Persistent URL to link to this item:


We present observations of the Rossiter-McLaughlin effect for two exoplanetary systems, revealing the orientations of their orbits relative to the rotation axes of their parent stars. HAT-P-4b is prograde, with a sky-projected spin-orbit angle of λ = –4.9 ± 11.9 deg. In contrast, HAT-P-14b is retrograde, with λ = 189.1 ± 5.1 deg. These results conform with a previously noted pattern among the stellar hosts of close-in giant planets: hotter stars have a wide range of obliquities and cooler stars have low obliquities. This, in turn, suggests that three-body dynamics and tidal dissipation are responsible for the short-period orbits of many exoplanets. In addition, our data revealed a third body in the HAT-P-4 system, which could be a second planet or a companion star.

Item Type:Article
Related URLs:
URLURL TypeDescription
Winn, Joshua N.0000-0002-4265-047X
Howard, Andrew W.0000-0001-8638-0320
Johnson, John Asher0000-0001-9808-7172
Marcy, Geoffrey W.0000-0002-2909-0113
Isaacson, Howard0000-0002-0531-1073
Shporer, Avi0000-0002-1836-3120
Bakos, Gáspár Á.0000-0001-7204-6727
Hartman, Joel D.0000-0001-8732-6166
Holman, Matthew J.0000-0002-1139-4880
Crepp, Justin R.0000-0003-0800-0593
Morton, Timothy D.0000-0002-8537-5711
Additional Information:© 2011 American Astronomical Society. Received 2010 October 6; accepted 2010 December 3; published 2011 January 13. We thank Teruyuki Hirano for interesting discussions related to this work, Amaury Triaud and the anonymous referee for insightful comments on the manuscript, and John Southworth for making available his useful code JKTLD for calculating theoretical limb-darkening coefficients. We gratefully acknowledge support from the NASA Origins program through awards NNX09AD36G and NNX09AB33G, and the MIT Class of 1942. S.A. acknowledges support from an NWO Rubicon fellowship. This paper uses observations obtained with facilities of the Las Cumbres Observatory Global Telescope. Some data presented herein were obtained at the W.M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration, and was made possible by the generous financial support of the W.M. Keck Foundation. We extend special thanks to those of Hawaiian ancestry on whose sacred mountain of Mauna Kea we are privileged to be guests. Without their generous hospitality, the Keck observations presented herein would not have been possible. Facilities: Keck:I (HIRES), FLWO:1.2m (KeplerCam), FTN (Spectral)
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
Massachusetts Institute of Technology (MIT)UNSPECIFIED
Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO)UNSPECIFIED
Subject Keywords:planetary systems – planets and satellites: formation – planet–star interactions – stars: rotation
Issue or Number:2
Classification Code:PACS ; 97.82.-j; 95.85.Kr; 97.10.Wn; 97.10.Kc
Record Number:CaltechAUTHORS:20110228-105841915
Persistent URL:
Official Citation:Joshua N. Winn et al. 2011 The Astronomical Journal 141 63 doi: 10.1088/0004-6256/141/2/63
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:22545
Deposited By: Benjamin Perez
Deposited On:28 Feb 2011 21:40
Last Modified:09 Mar 2020 13:18

Repository Staff Only: item control page