HAT‐P‐1b: A Large‐Radius, Low‐Density Exoplanet Transiting One Member of a Stellar Binary

Bakos, G. Á.; Noyes, R. W.; Kovács, G.; Latham, David W.; Sasselov, Dimitar; Torres, Guillermo; Fischer, Debra A.; Stefanik, R. P.; Sato, B.; Johnson, J. A.; Pál, András; Marcy, Geoffrey W.; Butler, R. Paul; Esquerdo, Gilbert A.; Stanek, K. Z.; Lázár, J.; Papp, I.; Sári, P.; Sipőcz, Brigitta

doi:10.1086/509874

Cited by 240 publications

(212 citation statements)

References 51 publications

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“…Some of the hot Jupiters appear to be in multiple systems but this appears unrelated to other parameters such as eccentricity or misalignment. Examples are: HD 80606 (Naef et al 2001), HD 189733 (Bakos et al 2006), Hat-P-1 (Bakos et al 2007), WASP-8 (Queloz et al 2010), Hat-P-7 (Winn et al 2009b), WASP-2, TrES-2 and TrES-4 (Daemgen et al 2009). …”

Section: Correlations Between Parametersmentioning

confidence: 99%

Spin-orbit angle measurements for six southern transiting planets

Triaud

Cameron

Queloz

et al. 2010

A&A

435

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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Section: Correlations Between Parametersmentioning

confidence: 99%

Spin-orbit angle measurements for six southern transiting planets

Triaud

Cameron

Queloz

et al. 2010

A&A

435

440

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“…HAT-P-1b is the first planet discovered by the HATNet project (Bakos et al 2002(Bakos et al , 2007 and the planet orbits one of the stars in a visual binary (Bakos et al 2007;Liu et al 2014). There have been many follow-up transit observations of HAT-P-1b (e.g.…”

Section: Hat-p-1bmentioning

confidence: 99%

“…1). The stellar binary was used as the main reference star in our light-curve analysis since the two stars are nearly identical in their stellar parameters (Bakos et al 2007;Liu et al 2014) and will experience similar variations due to the atmosphere (the stars are only separated by 11 arcsec). Our light-curve solution (Table 8) and derived planetary parameters (Table 13) agree with previous studies.…”

Section: Hat-p-1bmentioning

confidence: 99%

Ground-based near-UV observations of 15 transiting exoplanets: constraints on their atmospheres and no evidence for asymmetrical transits

Turner

Pearson

Biddle

et al. 2016

Mon. Not. R. Astron. Soc.

109

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Transits of exoplanets observed in the near-UV have been used to study the scattering properties of their atmospheres and possible star-planet interactions. We observed the primary transits of 15 exoplanets (CoRoT-1b, GJ436b, HAT-P-1b, HAT-P-13b, HAT-P-16b, HAT-P-22b, TrES2b, in the near-UV and several optical photometric bands to update their planetary parameters, ephemerides, search for a wavelength dependence in their transit depths to constrain their atmospheres, and determine if asymmetries are visible in their light curves. Here, we present the first ground-based near-UV light curves for 12 of the targets (CoRoT1b, GJ436b, HAT-P-1b, HAT-P-13b, HAT-P-22b, TrES-2b, TrES-4b, WASP-1b, WASP-33b, WASP-36b, WASP-48b, and WASP-77Ab). We find that none of the near-UV transits exhibit any non-spherical asymmetries, this result is consistent with recent theoretical predictions by Ben-Jaffel et al. and Turner et al. The multiwavelength photometry indicates a constant transit depth from near-UV to optical wavelengths in 10 targets (suggestive of clouds), and a varying transit depth with wavelength in 5 targets (hinting at Rayleigh or aerosol scattering in their atmospheres). We also present the first detection of a smaller near-UV transit depth than that measured in the optical in WASP-1b and a possible opacity source that can cause such radius variations is currently unknown. WASP-36b also exhibits a smaller near-UV transit depth at

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“…Half of the studies mentioned in Table 3 are based on spectra taken with the Keck HIRES spectrograph, although with slightly different configurations. Bakos et al (2007b), Bakos et al (2007a), Kovács et al (2007), Noyes et al (2008), and Pál et al (2008) obtained Keck HIRES spectra with a resolving power of λ Δλ = 55 000, while the HIRES spectra used by Sozzetti et al (2007Sozzetti et al ( , 2009a have λ Δλ = 71 000. Burke et al (2007) and McCullough et al (2006) obtained spectra with λ Δλ = 60 000 with the Échelle spectrograph at the Harlan J. Smith telescope.…”

Section: Small Amount Of Variety Between Spectrographs Usedmentioning

confidence: 99%

A homogeneous spectroscopic analysis of host stars of transiting planets

Eiff

Santos

Sousa

et al. 2009

A&A

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Context. The analysis of transiting extra-solar planets provides an enormous amount of information about the formation and evolution of planetary systems. A precise knowledge of the host stars is necessary to derive the planetary properties accurately. The properties of the host stars, especially their chemical composition, are also of interest in their own right. Aims. Information about planet formation is inferred by, among others, correlations between different parameters such as the orbital period and the metallicity of the host stars. The stellar properties studied should be derived as homogeneously as possible. The present work provides new, uniformly derived parameters for 13 host stars of transiting planets. Methods. Effective temperature, surface gravity, microturbulence parameter, and iron abundance were derived from spectra of both high signal-to-noise ratio and high resolution by assuming iron excitation and ionization equilibria. Results. For some stars, the new parameters differ from previous determinations, which is indicative of changes in the planetary radii. A systematic offset in the abundance scale with respect to previous assessments is found for the TrES and HAT objects. Our abundance measurements are remarkably robust in terms of the uncertainties in surface gravities. The iron abundances measured in the present work are supplemented by all previous determinations using the same analysis technique. The distribution of iron abundance then agrees well with the known metal-rich distribution of planet host stars. To facilitate future studies, the spectroscopic results of the current work are supplemented by the findings for other host stars of transiting planets, for a total dataset of 50 objects.

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HAT‐P‐1b: A Large‐Radius, Low‐Density Exoplanet Transiting One Member of a Stellar Binary

Cited by 240 publications

References 51 publications

Spin-orbit angle measurements for six southern transiting planets

Spin-orbit angle measurements for six southern transiting planets

Ground-based near-UV observations of 15 transiting exoplanets: constraints on their atmospheres and no evidence for asymmetrical transits

A homogeneous spectroscopic analysis of host stars of transiting planets

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