A high stellar obliquity in the WASP-7 exoplanetary system

Simon Albrecht; Joshua N. Winn; R. Paul Butler; Jeffrey D. Crane; Stephen A. Shectman; Ian B. Thompson; Teruyuki Hirano; Robert A. Wittenmyer

doi:10.1088/0004-637X/744/2/189

A high stellar obliquity in the WASP-7 exoplanetary system

Simon Albrecht, Joshua N. Winn, R. Paul Butler, Jeffrey D. Crane, Stephen A. Shectman, Ian B. Thompson, Teruyuki Hirano, Robert A. Wittenmyer

Research output: Contribution to journal › Article › peer-review

46 Scopus citations

Abstract

We measure a tilt of 86° ± 6° between the sky projections of the rotation axis of the WASP-7 star and the orbital axis of its close-in giant planet. This measurement is based on observations of the Rossiter-McLaughlin (RM) effect with the Planet Finder Spectrograph on the Magellan II telescope. The result conforms with the previously noted pattern among hot-Jupiter hosts, namely, that the hosts lacking thick convective envelopes have high obliquities. Because the planet's trajectory crosses a wide range of stellar latitudes, observations of the RM effect can in principle reveal the stellar differential rotation profile; however, with the present data the signal of differential rotation could not be detected. The host star is found to exhibit radial-velocity noise ("stellar jitter") with an amplitude of ≈ 30 m s^-1 over a timescale of days.

Original language	English (US)
Article number	189
Journal	Astrophysical Journal
Volume	744
Issue number	2
DOIs	https://doi.org/10.1088/0004-637X/744/2/189
State	Published - Jan 10 2012
Externally published	Yes

All Science Journal Classification (ASJC) codes

Astronomy and Astrophysics
Space and Planetary Science

Keywords

planetary systems
planets and satellites: formation
planetstar interactions
stars: individual (WASP-7)
stars: rotation
techniques: spectroscopic

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10.1088/0004-637X/744/2/189

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title = "A high stellar obliquity in the WASP-7 exoplanetary system",

abstract = "We measure a tilt of 86° ± 6° between the sky projections of the rotation axis of the WASP-7 star and the orbital axis of its close-in giant planet. This measurement is based on observations of the Rossiter-McLaughlin (RM) effect with the Planet Finder Spectrograph on the Magellan II telescope. The result conforms with the previously noted pattern among hot-Jupiter hosts, namely, that the hosts lacking thick convective envelopes have high obliquities. Because the planet's trajectory crosses a wide range of stellar latitudes, observations of the RM effect can in principle reveal the stellar differential rotation profile; however, with the present data the signal of differential rotation could not be detected. The host star is found to exhibit radial-velocity noise ({"}stellar jitter{"}) with an amplitude of ≈ 30 m s-1 over a timescale of days.",

keywords = "planetary systems, planets and satellites: formation, planetstar interactions, stars: individual (WASP-7), stars: rotation, techniques: spectroscopic",

author = "Simon Albrecht and Winn, {Joshua N.} and Butler, {R. Paul} and Crane, {Jeffrey D.} and Shectman, {Stephen A.} and Thompson, {Ian B.} and Teruyuki Hirano and Wittenmyer, {Robert A.}",

year = "2012",

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doi = "10.1088/0004-637X/744/2/189",

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T1 - A high stellar obliquity in the WASP-7 exoplanetary system

AU - Albrecht, Simon

AU - Winn, Joshua N.

AU - Butler, R. Paul

AU - Crane, Jeffrey D.

AU - Shectman, Stephen A.

AU - Thompson, Ian B.

AU - Hirano, Teruyuki

AU - Wittenmyer, Robert A.

PY - 2012/1/10

Y1 - 2012/1/10

N2 - We measure a tilt of 86° ± 6° between the sky projections of the rotation axis of the WASP-7 star and the orbital axis of its close-in giant planet. This measurement is based on observations of the Rossiter-McLaughlin (RM) effect with the Planet Finder Spectrograph on the Magellan II telescope. The result conforms with the previously noted pattern among hot-Jupiter hosts, namely, that the hosts lacking thick convective envelopes have high obliquities. Because the planet's trajectory crosses a wide range of stellar latitudes, observations of the RM effect can in principle reveal the stellar differential rotation profile; however, with the present data the signal of differential rotation could not be detected. The host star is found to exhibit radial-velocity noise ("stellar jitter") with an amplitude of ≈ 30 m s-1 over a timescale of days.

AB - We measure a tilt of 86° ± 6° between the sky projections of the rotation axis of the WASP-7 star and the orbital axis of its close-in giant planet. This measurement is based on observations of the Rossiter-McLaughlin (RM) effect with the Planet Finder Spectrograph on the Magellan II telescope. The result conforms with the previously noted pattern among hot-Jupiter hosts, namely, that the hosts lacking thick convective envelopes have high obliquities. Because the planet's trajectory crosses a wide range of stellar latitudes, observations of the RM effect can in principle reveal the stellar differential rotation profile; however, with the present data the signal of differential rotation could not be detected. The host star is found to exhibit radial-velocity noise ("stellar jitter") with an amplitude of ≈ 30 m s-1 over a timescale of days.

KW - planetary systems

KW - planets and satellites: formation

KW - planetstar interactions

KW - stars: individual (WASP-7)

KW - stars: rotation

KW - techniques: spectroscopic

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DO - 10.1088/0004-637X/744/2/189

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VL - 744

JO - Astrophysical Journal

JF - Astrophysical Journal

IS - 2

M1 - 189

ER -

A high stellar obliquity in the WASP-7 exoplanetary system

Abstract

All Science Journal Classification (ASJC) codes

Keywords

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