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Long-term monitoring of WASP-19 b: Signs of apsidal precession and molecular signatures

Fuente: arXiv

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Main Authors:	Rajkumar, A. R., Bayo, A., Peng, P., Tregloan-Reed, J., Southworth, J., Hinse, Tobias C., Alegre, L. G., Amadio, F., Andersen, M., Bach-Møller, N., Basilicata, M., Bonavita, M., Bozza, V., Burgdorf, M. J., Cannon, R. E., Columba, G., Dominik, M., Donaldson, A., Jaimes, R. Figuera, Fynbo, J., Hundertmark, M., Jørgensen, U. G., Khalouei, E., Korhonen, H., Longa-Peña, P., Rabus, M., Rahvar, S., Rendell-Bhatti, H., Rota, P., Rożek, A., Sajadian, S., Skottfelt, J., Snodgrass, C.
Format:	Preprint
Published:	2026
Subjects:	Earth and Planetary Astrophysics
Online Access:	Acceder al recurso
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_version_	1866910051421126656
author	Rajkumar, A. R. Bayo, A. Peng, P. Tregloan-Reed, J. Southworth, J. Hinse, Tobias C. Alegre, L. G. Amadio, F. Andersen, M. Bach-Møller, N. Basilicata, M. Bonavita, M. Bozza, V. Burgdorf, M. J. Cannon, R. E. Columba, G. Dominik, M. Donaldson, A. Jaimes, R. Figuera Fynbo, J. Hundertmark, M. Jørgensen, U. G. Khalouei, E. Korhonen, H. Longa-Peña, P. Rabus, M. Rahvar, S. Rendell-Bhatti, H. Rota, P. Rożek, A. Sajadian, S. Skottfelt, J. Snodgrass, C.
author_facet	Rajkumar, A. R. Bayo, A. Peng, P. Tregloan-Reed, J. Southworth, J. Hinse, Tobias C. Alegre, L. G. Amadio, F. Andersen, M. Bach-Møller, N. Basilicata, M. Bonavita, M. Bozza, V. Burgdorf, M. J. Cannon, R. E. Columba, G. Dominik, M. Donaldson, A. Jaimes, R. Figuera Fynbo, J. Hundertmark, M. Jørgensen, U. G. Khalouei, E. Korhonen, H. Longa-Peña, P. Rabus, M. Rahvar, S. Rendell-Bhatti, H. Rota, P. Rożek, A. Sajadian, S. Skottfelt, J. Snodgrass, C.
contents	With more than 6000 exoplanets discovered so far, about 12 percent are hot Jupiters. Their large sizes and short orbital periods make them valuable targets for studying planetary formation, atmospheres, and orbital evolution. We present a homogeneous analysis of the WASP-19 b system using a 15 year dataset to investigate both its orbital dynamics and atmospheric properties. We test whether the transit times show evidence for tidal orbital decay, apsidal precession, or periodic perturbations from an additional body, and we also construct a photometric transmission spectrum. Multi-wavelength light curves are modeled with PRISM to account for starspots, and linear, quadratic, and cubic ephemeris models are fitted to the transit timing residuals. Our dataset includes 27 new transits and reveals no statistically significant periodic signal. Although none of the tested models fully reproduces the timing scatter, the transit times show systematic deviations from a constant period and are best described by the cubic ephemeris, indicating a slow long-term trend over the full baseline. This behavior is more consistent with gradual apsidal precession than with monotonic tidal decay. A precession model yields a rate of 1.00 +/- 0.12 x 10^-4 rad per orbit and a planetary Love number k2p = 0.107 +/- 0.08. The transmission spectrum shows signatures of Na, K, and H2O, with no strong evidence for TiO or VO. These results suggest that apsidal precession may dominate the long-term orbital evolution of WASP-19 b. Continued high-precision timing and spectroscopic observations are needed to further test this scenario.
format	Preprint
id	arxiv_https___arxiv_org_abs_2603_12395
institution	arXiv
publishDate	2026
record_format	arxiv
spellingShingle	Long-term monitoring of WASP-19 b: Signs of apsidal precession and molecular signatures Rajkumar, A. R. Bayo, A. Peng, P. Tregloan-Reed, J. Southworth, J. Hinse, Tobias C. Alegre, L. G. Amadio, F. Andersen, M. Bach-Møller, N. Basilicata, M. Bonavita, M. Bozza, V. Burgdorf, M. J. Cannon, R. E. Columba, G. Dominik, M. Donaldson, A. Jaimes, R. Figuera Fynbo, J. Hundertmark, M. Jørgensen, U. G. Khalouei, E. Korhonen, H. Longa-Peña, P. Rabus, M. Rahvar, S. Rendell-Bhatti, H. Rota, P. Rożek, A. Sajadian, S. Skottfelt, J. Snodgrass, C. Earth and Planetary Astrophysics With more than 6000 exoplanets discovered so far, about 12 percent are hot Jupiters. Their large sizes and short orbital periods make them valuable targets for studying planetary formation, atmospheres, and orbital evolution. We present a homogeneous analysis of the WASP-19 b system using a 15 year dataset to investigate both its orbital dynamics and atmospheric properties. We test whether the transit times show evidence for tidal orbital decay, apsidal precession, or periodic perturbations from an additional body, and we also construct a photometric transmission spectrum. Multi-wavelength light curves are modeled with PRISM to account for starspots, and linear, quadratic, and cubic ephemeris models are fitted to the transit timing residuals. Our dataset includes 27 new transits and reveals no statistically significant periodic signal. Although none of the tested models fully reproduces the timing scatter, the transit times show systematic deviations from a constant period and are best described by the cubic ephemeris, indicating a slow long-term trend over the full baseline. This behavior is more consistent with gradual apsidal precession than with monotonic tidal decay. A precession model yields a rate of 1.00 +/- 0.12 x 10^-4 rad per orbit and a planetary Love number k2p = 0.107 +/- 0.08. The transmission spectrum shows signatures of Na, K, and H2O, with no strong evidence for TiO or VO. These results suggest that apsidal precession may dominate the long-term orbital evolution of WASP-19 b. Continued high-precision timing and spectroscopic observations are needed to further test this scenario.
title	Long-term monitoring of WASP-19 b: Signs of apsidal precession and molecular signatures
topic	Earth and Planetary Astrophysics
url	https://arxiv.org/abs/2603.12395