Towards Doppler eclipse mapping of hot Jupiters
Year: 2026
Type: article
Abstract: Context. In the last decade, ground-based high-resolution spectroscopy (HRS) has emerged as a powerful method to probe exoplanet atmospheres both in transit and thermal emission. With tens of instruments worldwide, HRS is now producing numerous observations on many targets, revealing these planet’s thermal, compositional, and dynamical structure in three dimensions. As HRS science continues to mature, novel strategies and interpretation tools will be key to extracting the maximal scientific output from these rich datasets. Aims. For this article we investigated the potential of exploiting eclipses in order to retrieve spatial constraints on exoplanet dayside atmospheres with HRS, an approach that has been successfully applied at lower spectral resolutions with space-based facilities. Methods. To attempt this, we obtained an observation programme covering eight eclipses (ingress and egress) of the ultra-hot Jupiter WASP-33b using the (R ~ 70 000) SPIRou spectropolarimeter on the 3.6 m CFHT. We analysed these data with the publicly available ATMOSPHERIX pipeline, which we combined with the starry Python package to fit the eclipse mapping signal. Additionally, we performed injection-recovery tests on archival SPIRou data to evaluate the detection limits that could be reached with further observations. Results. From eight ingresses and egresses of WASP-33b, we obtain a tentative detection of CO consistent with the literature values and archival SPIRou data, validating that eclipses may be stacked coherently to boost detection limits. In combination with longer phase-coverage dayside data, our eclipses marginally improve constraints on the planetary rotation velocity. Through injection recovery tests, we show that our results are scaling according to expectations for a synchronously rotating WASP-33b, implying that a further 15 eclipses with SPIRou (~20 h) would be required to measure the planet’s rotation using this method. While our study reveals the potential of HRS eclipses observations, it also highlights the importance of solving the remaining challenges in data processing for short time series and/or slowly accelerating planets ahead of the next generation of telescopes.
Source: Astronomy and Astrophysics
Institutions: Centre National de la Recherche Scientifique, Institut de Planétologie et d'Astrophysique de Grenoble, McGill University, Université Toulouse III - Paul Sabatier, Institut de Recherche en Astrophysique et Planétologie, Centro de Astrobiología, Université Côte d'Azur, Lagrange Laboratory, Observatoire de la Côte d’Azur, Université de Montréal
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $1,865
Funders: National Science Foundation, National Aeronautics and Space Administration, Ministerio de Ciencia, Innovación y Universidades, Agence Nationale de la Recherche, Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung, Centre National d’Etudes Spatiales, Mitacs, Centre National de la Recherche Scientifique, National Research Council Canada, Agencia Estatal de Investigación
Awards: EXOplanet Atmospheres Through Multi-phase Observations, G1105844351, G1175115578, G2121614283, G2262748287, G292453335, G294895050, G300979063, G3470217882, G3480869486, G3807624569, G4085408077, G425668148, G491712853, G5080475149, G5635532810, G5753977096, Probing Exoplanet Atmospheres: Harnessing the Synergy of JWST and High-Resolution Spectrographs, G593054264, G7084143925, G7395345766, VLSI-Systeme mit optischen Verbindungen - Vorstudie der technologischen Machbarkeit -, G7805626310, G7863371703, G8345352404, G8497050386, G8608281586, G8667377315, G8783516428, G8964069747
OpenAlex ID: W7161776172