Searching for candidates of orbital decays among transit exoplanets

Yeh, Li-Chin; Jiang, Ing-Guey; A-thano, Napaporn

doi:10.1016/j.newast.2023.102130

“…Ivshina and Winn [30] found a variation near the 3σ limit of Ṗ = −3.54 ± 1.18 ms year −1 that agrees well with our values for the orbital decay of WASP-19 b. Finally, Yeh et al [20] observed variations in transit times but did not attribute them to orbital decay.…”

Section: Discussionsupporting

confidence: 87%

“…Orbital decay can be detected through its effect on the timing of transits due to its change in orbital period (e.g., [13,14]). This approach found evidence for orbital decay in WASP-12 b [15][16][17][18][19][20] and Kepler-1658 b [21]. Among the USP gas giant planets, WASP-19 b, with an orbital period of 0.78 days, has emerged as a prime target for the search for orbital decay using transit timings [22][23][24][25].…”

Section: Introductionmentioning

confidence: 99%

“…The analysis of WASP-19 b's transit timings and the exploration of potential orbital decay have been subjects of numerous studies, yielding conflicting outcomes [20,24,[26][27][28][29][30][31]. While some studies report significant orbital period changes [24,28], others find no evidence for a shrinking orbit [20,26,27,[29][30][31]. Stellar spot activity, as detected by several studies [26,31,32], may contribute to these inconsistencies, as highlighted by Patra et al [24].…”

Section: Introductionmentioning

confidence: 99%

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Update on WASP-19

Korth,

Parviainen

2023

Universe

1

0

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Tidal interaction between a star and a close-in massive exoplanet causes the planetary orbit to shrink and eventually leads to tidal disruption. Understanding orbital decay in exoplanetary systems is crucial for advancing our knowledge of planetary formation and evolution. Moreover, it sheds light on the broader question of the long-term stability of planetary orbits and the intricate interplay of gravitational forces within stellar systems. Analyzing Transiting Exoplanet Survey Satellite (TESS) data for the ultra-short period gas giant WASP-19, we aim to measure orbital period variations and constrain the stellar tidal quality parameter. For this, we fitted the TESS observations together with two WASP-19 transits observed using the Las Cumbres Observatory Global Telescope (LCOGT) and searched for orbital decay in combination with previously published transit times. As a result, we find a deviation from the constant orbital period at the 7σ level. The orbital period changes at a rate of P˙=−3.7±0.5msyear−1, which translates into a tidal quality factor of Q★′=(7±1)×105. We additionally modeled WASP-19 b’s phase curve using the new TESS photometry and obtained updated values for the planet’s eclipse depth, dayside temperature, and geometric albedo. We estimate an eclipse depth of 520±60 ppm, which is slightly higher than previous estimates and corresponds to a dayside brightness temperature of 2400±60 K and geometric albedo of 0.20±0.04.

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“…In the past few years, as observational baselines have passed the decade mark for many systems, a growing number of UHJs around main-sequence stars have been presented with suggestions that they may have decreasing orbital periods. These include HAT-P-19 b (Hagey et al 2022) Maciejewski et al 2021;Hagey et al 2022;Ivshina & Winn 2022;Yeh et al 2024); WASP-4 b (Bouma et al 2020;Hagey et al 2022;Harre et al 2023); WASP-19 b (Patra et al 2020;Ivshina & Winn 2022); WASP-32 b (but not significant; Sun et al 2023); WASP-43 b as reported by Sun et al (2018), though not by Hagey et al (2022); and XO-3 b (Ivshina & Winn 2022;Yang & Wei 2022). Many of these claimed detections are acknowledged in the original publications to be of marginal significance, however.…”

Section: Introductionmentioning

confidence: 91%

Doomed Worlds. I. No New Evidence for Orbital Decay in a Long-term Survey of 43 Ultrahot Jupiters

Adams,

Jackson,

Sickafoose

et al. 2024

Planet. Sci. J.

3

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Ultrahot Jupiters (UHJs) are likely doomed by tidal forces to undergo orbital decay and eventual disruption by their stars, but the timescale over which this process unfolds is unknown. We present results from a long-term project to monitor UHJ transits. We recovered WASP-12 b’s orbital decay rate of P ̇ = − 29.8 ± 1.6 ms yr−1, in agreement with prior work. Five other systems initially had promising nonlinear transit ephemerides. However, a closer examination of two—WASP-19 b and CoRoT-2 b, both with prior tentative detections—revealed several independent errors with the literature timing data; after correction, neither planet shows signs of orbital decay. Meanwhile, a potential decreasing period for TrES-1 b, P ̇ = − 16 ± 5 ms yr−1, corresponds to a tidal quality factor Q ⋆ ′ = 160 and likely does not result from orbital decay if driven by dissipation within the host star. Nominal period increases in two systems, WASP-121 b and WASP-46 b, rest on a small handful of points. Only 1/43 planets (WASP-12 b) in our sample is experiencing detectable orbital decay. For nearly half (20/42), we can rule out P ̇ as high as observed for WASP-12 b. Thus, while many UHJs could still be experiencing rapid decay that we cannot yet detect, a sizable subpopulation of UHJs are decaying at least an order of magnitude more slowly than WASP-12 b. Our reanalysis of Kepler-1658 b with no new data finds that it remains a promising orbital decay candidate. Finally, we recommend that the scientific community take steps to avoid spurious detections through better management of the multi-decade-spanning data sets needed to search for and study planetary orbital decay.

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Simultaneous multicolour transit photometry of hot Jupiters HAT-P-19b, HAT-P-51b, HAT-P-55b, and HAT-P-65b

Kang,

Chen,

Pallé

et al. 2024

Monthly Notices of the Royal Astronomical Society

2

0

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Accurate physical parameters of exoplanet systems are essential for further exploration of planetary internal structure, atmospheres, and formation history. We aim to use simultaneous multicolour transit photometry to improve the estimation of transit parameters, to search for transit timing variations (TTVs), and to establish which of our targets should be prioritised for follow-up transmission spectroscopy. We performed time series photometric observations of 12 transits for the hot Jupiters HAT-P-19b, HAT-P-51b, HAT-P-55b, and HAT-P-65b using the simultaneous four-colour camera MuSCAT2 on the Telescopio Carlos Sánchez. We collected 56 additional transit light curves from TESS photometry. To derive transit parameters, we modelled the MuSCAT2 light curves with Gaussian processes to account for correlated noise. To derive physical parameters, we performed EXOFASTv2 global fits to the available transit and radial velocity data sets, together with the Gaia DR3 parallax, isochrones, and spectral energy distributions. To assess the potential for atmospheric characterisation, we compared the multicolour transit depths with a flat line and a clear atmosphere model. We consistently refined the transit and physical parameters. We improved the orbital period and ephemeris estimates, and found no evidence for TTVs or orbital decay. The MuSCAT2 broadband transmission spectra of HAT-P-19b and HAT-P-65b are consistent with previously published low-resolution transmission spectra. We also found that, except for HAT-P-65b, the assumption of a planetary atmosphere can improve the fit to the MuSCAT2 data. In particular, we identified HAT-P-55b as a priority target among these four planets for further atmospheric studies using transmission spectroscopy.

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Searching for candidates of orbital decays among transit exoplanets

Cited by 4 publications

References 56 publications

Update on WASP-19

Update on WASP-19

Doomed Worlds. I. No New Evidence for Orbital Decay in a Long-term Survey of 43 Ultrahot Jupiters

Simultaneous multicolour transit photometry of hot Jupiters HAT-P-19b, HAT-P-51b, HAT-P-55b, and HAT-P-65b

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