Phase curve and variability analysis of <i>WASP</i>-12b using <i>TESS</i> photometry

Owens, Niall; Mooij, Ernst de; Watson, Chris; Hooton, Matthew J.

doi:10.1093/mnrasl/slab014

Cited by 16 publications

(14 citation statements)

References 42 publications

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“…Although numerous phase curves of hot Jupiters have also exhibited signals associated with Doppler boosting and tidal ellipsoidal distortion (e.g. Shporer et al 2014;Wong et al 2020b;Owens et al 2021), relations presented by Morris (1985), Morris & Naftilan (1993), and Shporer et al (2019) suggest that the amplitude of these signals for MASCARA-1 would be roughly 10 ppm and 25 ppm, respectively. As we would be unable to significantly detect signals of these size in the Spitzer phase curve and due to the limited phase coverage of the CHEOPS data, we did not fit for these signals in our model.…”

Section: Planetary Modelmentioning

confidence: 99%

Spi-OPS: Spitzer and CHEOPS confirm the near-polar orbit of MASCARA-1 b and reveal a hint of dayside reflection

Hooton

Hoyer

Kitzmann³

et al. 2022

A&A

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Context. The light curves of tidally locked hot Jupiters transiting fast-rotating, early-type stars are a rich source of information about both the planet and star, with full-phase coverage enabling a detailed atmospheric characterisation of the planet. Although it is possible to determine the true spin–orbit angle Ψ – a notoriously difficult parameter to measure – from any transit asymmetry resulting from gravity darkening induced by the stellar rotation, the correlations that exist between the transit parameters have led to large disagreements in published values of Ψ for some systems. Aims. We aimed to study these phenomena in the light curves of the ultra-hot Jupiter MASCARA-1 b, which is characteristically similar to well-studied contemporaries such as KELT-9 b and WASP-33 b. Methods. We obtained optical CHaracterising ExOPlanet Satellite (CHEOPS) transit and occultation light curves of MASCARA-1 b, and analysed them jointly with a Spitzer/IRAC 4.5 μm full-phase curve to model the asymmetric transits, occultations, and phase-dependent flux modulation. For the latter, we employed a novel physics-driven approach to jointly fit the phase modulation by generating a single 2D temperature map and integrating it over the two bandpasses as a function of phase to account for the differing planet–star flux contrasts. The reflected light component was modelled using the general ab initio solution for a semi-infinite atmosphere. Results. When fitting the CHEOPS and Spitzer transits together, the degeneracies are greatly diminished and return results consistent with previously published Doppler tomography. Placing priors informed by the tomography achieves even better precision, allowing a determination of Ψ = 72.1−2.4+2.5 deg. From the occultations and phase variations, we derived dayside and nightside temperatures of 3062−68+66 K and 1720 ± 330 K, respectively.Our retrieval suggests that the dayside emission spectrum closely follows that of a blackbody. As the CHEOPS occultation is too deep to be attributed to blackbody flux alone, we could separately derive geometric albedo Ag = 0.171−0.068+0.066 and spherical albedo As = 0.266−0.100+0.097 from the CHEOPS data, and Bond albedoAB = 0.057−0.101+0.083 from the Spitzer phase curve.Although small, the Ag and As indicate that MASCARA-1 b is more reflective than most other ultra-hot Jupiters, where H− absorption is expected to dominate. Conclusions. Where possible, priors informed by Doppler tomography should be used when fitting transits of fast-rotating stars, though multi-colour photometry may also unlock an accurate measurement of Ψ. Our approach to modelling the phase variations at different wavelengths provides a template for how to separate thermal emission from reflected light in spectrally resolved James Webb Space Telescope phase curve data.

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Section: Planetary Modelmentioning

confidence: 99%

Spi-OPS: Spitzer and CHEOPS confirm the near-polar orbit of MASCARA-1 b and reveal a hint of dayside reflection

Hooton

Hoyer

Kitzmann³

et al. 2022

A&A

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“…Turner et al (2021) analyzed the transits and secondary eclipses and used the measured timings to calculate a refined orbital decay rate for WASP-12b. The full-orbit phase curve of the WASP-12 system was analyzed independently by Owens et al (2021) in a standalone paper and by Wong et al (2021a) as part of a systematic phase-curve study of short-period exoplanet systems observed during the second year of the TESS mission.…”

Section: Observations 21 Tess Light Curvesmentioning

confidence: 99%

“…The light curves provided additional transit timings, which were used to refine the estimate of the planet's orbital decay rate (Turner et al 2021). Meanwhile, the planetary phase curve was analyzed by Owens et al (2021) and Wong et al (2021a), yielding a robust secondary eclipse measurement and broad constraints on the day-night temperature contrast. No evidence for significant orbit-toorbit variability in the dayside brightness was found in the TESS photometry.…”

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confidence: 99%

TESS Revisits WASP-12: Updated Orbital Decay Rate and Constraints on Atmospheric Variability

Wong,

Shporer,

Vissapragada

et al. 2022

Preprint

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After observing WASP-12 in the second year of the primary mission, the Transiting Exoplanet Survey Satellite (TESS) revisited the system in late 2021 during its extended mission. In this paper, we incorporate the new TESS photometry into a reanalysis of the transits, secondary eclipses, and phase curve. We also present a new K s -band occultation observation of WASP-12b obtained with the Palomar/WIRC instrument. The latest TESS photometry span three consecutive months, quadrupling the total length of the TESS WASP-12 light curve and extending the overall time baseline by almost two years. Based on the full set of available transit and occultation timings, we find that the orbital period is shrinking at a rate of −29.81 ± 0.94 ms yr −1 . The additional data also increase the measurement precision of the transit depth, orbital parameters, and phase-curve amplitudes. We obtain a secondary eclipse depth of 466 ± 35 ppm, a 2σ upper limit on the nightside brightness of 70 ppm, and a marginal 6 • .2 ± 2 • .8 eastward offset between the dayside hotspot and the substellar point. The voluminous TESS dataset allows us to assess the level of atmospheric variability on timescales of days, months, and years. We do not detect any statistically significant modulations in the secondary eclipse depth or day-night brightness contrast. Likewise, our measured K s -band occultation depth of 2810±390 ppm is consistent with most ∼2.2 µm observations in the literature.

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“…Maciejewski et al (2016) were the first to detect its decreasing orbital period, and subsequent studies have confirmed the period change (Patra et al 2017;Maciejewski et al 2018;Bailey & Goodman 2019;Baluev et al 2019) and established orbital decay as its cause (Yee et al 2020). The decaying orbit of WASP-12b was confirmed also using transit and occultation observations with NASA's Transiting Exoplanet Survey Satellite (TESS; Ricker et al 2015) (Turner et al 2021, see also Owens et al 2021). The decay rate of WASP-12b was found to be 32.53±1.62 msec yr −1 corresponding to an orbital decay timescale of τ = P/| Ṗ | = 2.90 ± 0.14 Myr (Turner et al 2021), shorter than the estimated mass-loss timescale of 300 Myr (Lai et al 2010;Jackson et al 2017).…”

Section: Introductionmentioning

confidence: 87%

Characterizing the WASP-4 system with TESS and radial velocity data: Constraints on the cause of the hot Jupiter's changing orbit and evidence of an outer planet

Turner,

Flagg,

Ridden-Harper

et al. 2021

Preprint

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Orbital dynamics provide valuable insights into the evolution and diversity of exoplanetary systems. Currently, only one hot Jupiter, WASP-12b, is confirmed to have a decaying orbit. Another, WASP-4b, exhibits hints of a changing orbital period that could be caused by orbital decay, apsidal precession, or the acceleration of the system towards the Earth. We have analyzed all data sectors from NASA's Transiting Exoplanet Survey Satellite together with all radial velocity (RV) and transit data in the literature to characterize WASP-4b's orbit. Our analysis shows that the full RV data set is consistent with no acceleration towards the Earth. Instead, we find evidence of a possible additional planet in the WASP-4 system, with an orbital period of ∼7000 days and M c sin(i) of 5.47 +0.44 −0.43 M Jup . Additionally, we find that the transit timing variations of all of the WASP-4b transits cannot be explained by the second planet but can be explained with either a decaying orbit or apsidal precession, with a slight preference for orbital decay. Assuming the decay model is correct, we find an updated period of 1.338231587±0.000000022 days, a decay rate of -7.33±0.71 msec year −1 , and an orbital decay timescale of τ = P/| Ṗ | = 15.77±1.57 Myr. If the observed decay results from tidal dissipation, we derive a modified tidal quality factor of Q = 5.1±0.9 ×10 4 , which is an order of magnitude lower than values derived for other hot Jupiter systems. However, more observations are needed to determine conclusively the cause of WASP-4b's changing orbit and confirm the existence of an outer companion.

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Phase curve and variability analysis of WASP-12b using TESS photometry

Cited by 16 publications

References 42 publications

Spi-OPS: Spitzer and CHEOPS confirm the near-polar orbit of MASCARA-1 b and reveal a hint of dayside reflection

Spi-OPS: Spitzer and CHEOPS confirm the near-polar orbit of MASCARA-1 b and reveal a hint of dayside reflection

TESS Revisits WASP-12: Updated Orbital Decay Rate and Constraints on Atmospheric Variability

Characterizing the WASP-4 system with TESS and radial velocity data: Constraints on the cause of the hot Jupiter's changing orbit and evidence of an outer planet

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