Orbital Orientations of Exoplanets: Hat-p-4b is Prograde and Hat-p-14b is Retrograde
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 retrog...
| Main Authors: | , , , , , , , , , , , |
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| Other Authors: | |
| Format: | Article |
| Language: | en_US |
| Published: |
IOP Publishing
2012
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| Online Access: | http://hdl.handle.net/1721.1/72100 https://orcid.org/0000-0002-4265-047X |
| Summary: | 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. |
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