The Rossiter‐McLaughlin Effect and Analytic Radial Velocity Curves for Transiting Extrasolar Planetary Systems

Ohta, Yuichi; Taruya, Atsushi; Suto, Yasushi

doi:10.1086/428344

Cited by 306 publications

(363 citation statements)

References 22 publications

(29 reference statements)

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“…The most popular one is to use the Rossiter-McLaughlin (RM) effect (Rossiter 1924, McLaughlin 1924, which reveals the sky-projected spin-orbit angle through spectroscopy (e.g., Ohta et al 2005, Hirano et al 2012. By combining the RM effect and asteroseismology, furthermore, threedimensional spin-orbit angle φ can be determined (Lund et al 2014, Benomar et al 2014.…”

Section: Summary and Discussionmentioning

confidence: 99%

Revisiting a gravity-darkened and precessing planetary system PTFO 8-8695: A spin–orbit non-synchronous case

Kamiaka

Masuda

Xue

et al. 2015

Publications of the Astronomical Society of Japan

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We reanalyse the time-variable lightcurves of the transiting planetary system PTFO 8-8695, in which a planet of 3 to 4 Jupiter mass orbits around a rapidly rotating pre-main-sequence star. Both the planetary orbital period P orb of 0.448 days and the stellar spin period P s less than 0.671 days are unusually short, which makes PTFO 8-8695 an ideal system to check the model of gravity darkening and nodal precession. While the previous analysis of PTFO 8-8695 assumed that the stellar spin and planetary orbital periods are the same, we extend the analysis by discarding the spin-orbit synchronous condition, and find three different classes of solutions roughly corresponding to the nodal precession periods of 199±16, 475±21, and 827 ± 53 days that reproduce the transit lightcurves observed in 2009 and 2010. We compare the predicted lightcurves of the three solutions against the photometry data of a few percent accuracy obtained at Koyama Astronomical Observatory in 2014 and 2015, and find that the solution with the precession period of 199 ± 16 days is preferred even though preliminary. Future prospect and implications to other transiting systems are briefly discussed.

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Section: Summary and Discussionmentioning

confidence: 99%

Revisiting a gravity-darkened and precessing planetary system PTFO 8-8695: A spin–orbit non-synchronous case

Kamiaka

Masuda

Xue

et al. 2015

Publications of the Astronomical Society of Japan

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“…We use the Ohta et al (2005) analytical description of the RM effect, and a Keplerian radialvelocity orbit. We compute the 3D position of the planet relative to the star at each date.…”

Section: Modelsmentioning

confidence: 99%

Spin-orbit misalignment in the HD 80606 planetary system

Pont

Hébrard

Irwin

et al. 2009

A&A

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We recently reported the photometric and spectroscopic detection of the primary transit of the 111-day-period, eccentric extra-solar planet HD 80606b, at Observatoire de Haute-Provence, France. The whole egress of the primary transit and a section of its central part were observed, allowing the measurement of the planetary radius, and evidence for a spin-orbit misalignment through the observation of the Rossiter-McLaughlin anomaly. The ingress not having been observed for this long-duration transit, uncertainties remained in the parameters of the system. We present here a refined, combined analysis of our photometric and spectroscopic data, together with further published radial velocities, ground-based photometry, and Spitzer photometry around the secondary eclipse, as well as new photometric measurements of HD 80606 acquired at Mount Hopkins, Arizona, just before the beginning of the primary transit. Although the transit is not detected in those new data, they provide an upper limit for the transit duration, which narrows down the possible behaviour of the Rossiter-McLaughlin anomaly in the unobserved part of the transit. We analyse the whole data with a Bayesian approach using a Markov-chain Monte Carlo integration on all available information. We find R p = 0.98 ± 0.03 R Jup for the planetary radius, and a total primary transit duration of 11.9 ± 1.3 h from first to fourth contact. Our analysis reinforces the hypothesis of spin-orbit misalignment in this system (alignment excluded at >95% level), with a positive projected angle between the planetary orbital axis and the stellar rotation (median solution λ ∼ 50 • ). As HD 80606 is a component of a binary system, the peculiar orbit of its planet could result from a Kozai mechanism.

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“…It was first observed for a planet by Queloz et al (2000). Several papers model this effect: Ohta et al (2005), Giménez (2006), Gaudi & Winn (2007).…”

Section: Introductionmentioning

confidence: 99%

Spin-orbit angle measurements for six southern transiting planets

Triaud

Cameron

Queloz

et al. 2010

A&A

423

440

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Context. Several competing scenarios for planetary-system formation and evolution seek to explain how hot Jupiters came to be so close to their parent stars. Most planetary parameters evolve with time, making it hard to distinguish between models. The obliquity of an orbit with respect to the stellar rotation axis is thought to be more stable than other parameters such as eccentricity. Most planets, to date, appear aligned with the stellar rotation axis; the few misaligned planets so far detected are massive (>2 M J ). Aims. Our goal is to measure the degree of alignment between planetary orbits and stellar spin axes, to search for potential correlations with eccentricity or other planetary parameters and to measure long term radial velocity variability indicating the presence of other bodies in the system. Methods. For transiting planets, the Rossiter-McLaughlin effect allows the measurement of the sky-projected angle β between the stellar rotation axis and a planet's orbital axis. Using the HARPS spectrograph, we observed the Rossiter-McLaughlin effect for six transiting hot Jupiters found by the WASP consortium. We combine these with long term radial velocity measurements obtained with CORALIE. We used a combined analysis of photometry and radial velocities, fitting model parameters with the Markov Chain Monte Carlo method. After obtaining β we attempt to statistically determine the distribution of the real spin-orbit angle ψ. Results. We found that three of our targets have β above 90 • : WASP-2b: β = 153 • +11 −15 , WASP-15b: β = 139.6 • +5.2 −4.3 and WASP17b: β = 148.5 • +5.1 −4.2 ; the other three (WASP-4b, WASP-5b and WASP-18b) have angles compatible with 0 • . We find no dependence between the misaligned angle and planet mass nor with any other planetary parameter. All six orbits are close to circular, with only one firm detection of eccentricity e = 0.00848 +0.00085 −0.00095 in WASP-18b. No long-term radial acceleration was detected for any of the targets. Combining all previous 20 measurements of β and our six and transforming them into a distribution of ψ we find that between about 45 and 85% of hot Jupiters have ψ > 30 • . Conclusions. Most hot Jupiters are misaligned, with a large variety of spin-orbit angles. We find observations and predictions using the Kozai mechanism match well. If these observational facts are confirmed in the future, we may then conclude that most hot Jupiters are formed from a dynamical and tidal origin without the necessity to use type I or II migration. At present, standard disc migration cannot explain the observations without invoking at least another additional process.

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The Rossiter‐McLaughlin Effect and Analytic Radial Velocity Curves for Transiting Extrasolar Planetary Systems

Cited by 306 publications

References 22 publications

Revisiting a gravity-darkened and precessing planetary system PTFO 8-8695: A spin–orbit non-synchronous case

Revisiting a gravity-darkened and precessing planetary system PTFO 8-8695: A spin–orbit non-synchronous case

Spin-orbit misalignment in the HD 80606 planetary system

Spin-orbit angle measurements for six southern transiting planets

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