TASTE V. A new ground-based investigation of orbital decay in the ultra-hot Jupiter WASP-12b
- 1Dipartimento di Fisica, Università di Trento, Via Sommarive 14, 38123 Povo (pietro.leonardi.1@studenti.unipd.it)
- 2Dipartimento di Fisica e Astronomia, Università degli Studi di Padova, Vicolo dell’Osservatorio 3, 35122 Padova, Italy
- 3INAF – Osservatorio Astronomico di Padova, Vicolo dell’Osservatorio 5, 35122 Padova, Italy
- 4Centro di Ateneo di Studi e Attività Spaziali “Giuseppe Colombo” (CISAS), Università degli Studi di Padova, Via Venezia 15, 35131 Padova, Italy
- 5INAF – Osservatorio Astronomico di Roma, Via Frascati 33, 00040 Monte Porzio Catone, Italy
- 6INAF – Osservatorio Astrofisico di Catania, via S. Sofia 78, 95123 Catania, Italy
- 7INAF - Osservatorio Astrofisico di Torino, Via Osservatorio 20, I-10025 Pino Torinese, Italy
The discovery of the first transiting hot Jupiters (HJs; giant planets on orbital periods shorter than P∼10 days) was announced more than twenty years ago. As both ground- and space-based follow-up observations are piling up, we are approaching the temporal baseline required to detect secular variations in their orbital parameters. In particular, several recent studies focused on constraining the efficiency of the tidal decay mechanism to better understand the evolutionary time scales of HJ migration and engulfment. This can be achieved by measuring a monotonic decrease of orbital period dP/dt<0 due to mechanical energy being dissipated by tidal friction. WASP-12b was the first HJ for which a tidal decay scenario appeared convincing, even though alternative explanations have been hypothesized. Here we present a new analysis based on 28 unpublished high-precision transit light curves gathered over a twelve-year baseline (an example of these light-curve can be seen in Fig. 2) and combined with all the available archival data, and an updated set of stellar parameters from HARPS-N high-resolution spectra, which are consistent with a main sequence scenario (see Fig.3), close to the hydrogen exhaustion in the core. Our values of dP/dt = −30.72±2.67 msec/year and Q'* = (2.13±0.18)×105 are statistically consistent with previous studies, and indicate that WASP-12 is undergoing fast tidal dissipation (see Fig.1). We additionally report the presence of an excess scatter in the timing data and discuss its possible origin.
Figures:
Fig.1: bserved minus calculated (O − C) diagram of WASP-12b for the unpublished transits collected at Asiago. A decreasing trend of the transit timing is visible over the 12-years of observations, comfirming the orbital decay scenario.
Fig.2: Example of transit light-curve of WASP-12 b collecte as part of the TASTE program
Fig.3: H-R diagram displaying the effective temperature Teff versus luminosity L/L_solar. WASP-12 is located in an ambiguous position, between the main sequence and the turn-off, but far away from the subgiant branch.
How to cite: Leonardi, P., Nascimbeni, V., Granata, V., Malavolta, L., Borsato, L., Biazzo, K., Lanza, A. F., Desidera, S., Piotto, G., Nardiello, D., Damasso, M., Cunial, A., and Bedin, L. R.: TASTE V. A new ground-based investigation of orbital decay in the ultra-hot Jupiter WASP-12b, Europlanet Science Congress 2024, Berlin, Germany, 8–13 Sep 2024, EPSC2024-1027, https://doi.org/10.5194/epsc2024-1027, 2024.
