Helio and Astero-Seismology and Exoplanets Search

    General
    Description

    The principal objectives of this project are: 1) to study the structure and dynamics of the solar interior, 2) to extend this study to other stars (either single or in binary systems), 3) to search for extrasolar planets using photometric methods (primarily by transits of their host stars) and their characterization with complementary radial velocity information.

    To reach our first objective, we use Helioseismology (analysis of the solar oscillation eigenmodes), a technique that enables us to infer the Sun's internal structure and dynamics with high accuracy. This project covers the various aspects necessary to attain the aforementioned objectives: instrumental and observational (with the international networks BiSON and GONG operating at the ”SolarLab” at Observatorio del Teide), reduction, analysis, and interpretation of data (in particular, the GOLF and VIRGO instruments aboard   ESA/SoHO satellite). Finally, theoretical developments in inversion techniques are carried out.

    Furthermore, Asteroseismology applies similar techniques to other oscillating stars to infer their evolutionary state as well as their internal structure and dynamics. Thanks to the high-quality photometric data collected by the CoRoT, Kepler, and TESS space missions, it is possible to extract global seismic parameters for hundreds of thousands of solar-like stars, from the main sequence through the red-giant phase. Stellar evolution models are used to find the model that best fits the observables (spectroscopic and individual mode frequencies), providing precise mass, radius, and age for the star. Binary stars provide additional strong constraints on these models and therefore allow testing the intricacies of internal stellar physics.

    Precise exoplanet characterization is critically dependent on an accurate knowledge of the host star. In particular, a reliable determination of the stellar age is required to constrain the age and evolutionary state of the planetary system, and to place robust limits on long-term habitability. At the interface between asteroseismology and exoplanet science, detailed seismic modeling of host stars is used to refine the ages of planetary systems. Strong involvement is ensured in the preparation of the ESA PLATO mission (launch expected at the end of 2026), including light-curve calibration, contributions to the science calibration and validation input catalog (scvPIC), proposals for complementary science, and ground-based follow-up observations.

    For this project, ground-based observations with the observational facilities available to IAC researchers, in particular at OCAN (Observatorios de Canarias), are key. In particular, ongoing observations with the ground-based, high-precision spectrographs on the SONG (Stellar Observations Network Group) and the Las Cumbres Observatory Network (LCO) are being conducted to improve the spectroscopic and seismic characterization of oscillating stars and to identify binary systems.

    Principal investigator

    Milestones

    1. We produced and published a state-of-the-art characterization of the stars observed by the Kepler mission in terms of their color-magnitude diagram (CMD) and binarity using data from Gaia DR3 (Godoy-Rivera et al. 2026, A&A, 696, A243)
    2. In Grossmann et al. (2025, A&A, 696, A42) we used asteroseismic and binary constraints to model the red giant binary system KIC 9163796. We successfully determined the age of the system with a relative precision of less than 10%. We thereby showed that combining asteroseismology with constraints from binarity can significantly improve age precision.
    3. The study of the magnetic activity of more than 50,000 solar-like stars observed by the Kepler mission was published (Mathur et al. 2025, ApJ, 982, 11). The analysis showed different behaviours of the evolution of magnetic activity with spectral type. This work highlights that the level of magnetic activity of the Sun is similar to its peers.
    4. We studied the recent photometric evolution of the symbiotic recurrent nova T CrB, eagerly awaited to erupt by the community. We showed that the proposed observational indicators do not reliably predict the outburst, which may occur even without a clear precursor (Merc et al., MNRAS Letters, 541, L14).

    Related publications

    Revisiting symbiotic binaries with interferometry: I. The PIONIER archival collection 2025A&A...695A..61M
    Transit-timing variations in the AU Mic system observed with CHEOPS 2025A&A...694A.137B
    APOKASC-3: The Third Joint Spectroscopic and Asteroseismic Catalog for Evolved Stars in the Kepler Fields 2025ApJS..276...69P
    TOI-2458 b: A mini-Neptune consistent with in situ hot Jupiter formation 2025A&A...693A.235S
    CHEOPS observations confirm nodal precession in the WASP-33 system 2025A&A...693A.128S
    Symbiotic stars, weird novae, and related embarrassing binaries 2024NatAs...8.1504M
    A possible misaligned orbit for the young planet AU Mic c 2025MNRAS.536.2046Y
    Unequivocal detection of the tidal deformation of a red giant in a binary system via interferometry 2024A&A...692A.218M
    Hints of a close outer companion to the ultra-hot Jupiter TOI-2109 b 2024A&A...692A.254H
    The CHEOPS view of the climate of WASP-3 b 2024A&A...692A.129S
    Seismic differences between solar magnetic cycles 23 and 24 for low-degree modes 2024A&A...691L..20G
    Architecture of TOI-561 planetary system 2024MNRAS.535.2763P
    An ultra-short-period super-Earth with an extremely high density and an outer companion 2024NatSR..1427219L
    The curious case of 2MASS J15594729+4403595, an ultra-fast M2 dwarf with possible Rieger cycles 2024A&A...691A.117M
    The K2-24 planetary system revisited by CHEOPS 2024A&A...690A.349N
    Perspectives on the physics of late-type stars from beyond low earth orbit, the moon and mars 2024npjMG..10...96M
    Five new eclipsing binaries with low-mass companions 2024A&A...690A.168L
    HR 10 as seen by CHEOPS and TESS: Revealing δ Scuti pulsations, granulation-like signal and hint for transients 2024A&A...690A..73S
    Measuring stellar surface rotation and activity with the PLATO mission: I. Strategy and application to simulated light curves 2024A&A...689A.229B
    Photo-dynamical characterisation of the TOI-178 resonant chain. Exploring the robustness of transit-timing variations and radial velocity mass characterisations 2024A&A...688A.211L
    Characterisation of the warm-Jupiter TOI-1130 system with CHEOPS and a photo-dynamical approach 2024A&A...689A..52B
    Unveiling the internal structure and formation history of the three planets transiting HIP 29442 (TOI-469) with CHEOPS 2024A&A...688A.223E
    TOI-1408: Discovery and Photodynamical Modeling of a Small Inner Companion to a Hot Jupiter Revealed by Transit Timing Variations 2024ApJ...971L..28K
    A low-mass sub-Neptune planet transiting the bright active star HD 73344 2024A&A...688A..14S
    TOI-757 b: an eccentric transiting mini-Neptune on a 17.5-d orbit 2024MNRAS.533....1A
    CHEOPS in-flight performance. A comprehensive look at the first 3.5 yr of operations 2024A&A...687A.302F
    Detection of an Earth-sized exoplanet orbiting the nearby ultracool dwarf star SPECULOOS-3 2024NatAs...8..865G
    Gaia22dkvLb: A Microlensing Planet Potentially Accessible to Radial-velocity Characterization 2024AJ....168...62W
    Precise characterisation of HD 15337 with CHEOPS: A laboratory for planet formation and evolution 2024A&A...686A.282R
    HIP 41378 observed by CHEOPS: Where is planet d? 2024A&A...686L..18S
    Characterisation of the TOI-421 planetary system using CHEOPS, TESS, and archival radial velocity data 2024A&A...686A.301K
    Detailed cool star flare morphology with CHEOPS and TESS*** 2024A&A...686A.239B
    Kepler main-sequence solar-like stars: surface rotation and magnetic-activity evolution 2024FrASS..1156379S
    Magnetic activity of red giants: Correlation between the amplitude of solar-like oscillations and chromospheric indicators 2024A&A...686A..93G
    Discovery of a dormant 33 solar-mass black hole in pre-release Gaia astrometry 2024A&A...686L...2G
    Atmospheric Parameters and Abundances of Cool Red Giant Stars 2024PASP..136e4202D
    The tidal deformation and atmosphere of WASP-12 b from its phase curve★ 2024A&A...685A..63A
    Discovery of two warm mini-Neptunes with contrasting densities orbiting the young K3V star TOI-815 2024A&A...685A...5P
    The APO-K2 Catalog. II. Accurate Stellar Ages for Red Giant Branch Stars across the Milky Way 2024AJ....167..208W
    Nature versus nurture: distinguishing effects from stellar processing and chemical evolution on carbon and nitrogen in red giant stars 2024MNRAS.530..149R
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    PLAnetary Transits and Oscillations of stars (PLATO) is the third medium-class mission in ESA's Cosmic Vision programme. Its objective is to find and study a large number of extrasolar planetary systems, with emphasis on the properties of terrestrial planets in the habitable zone around solar-like stars
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    Deeg Deeg