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

    Acoustic oscillations and dynamo action in the G8 sub-giant EK Eridani 2019A&A...628A.106B
    Influence of magnetic activity on the determination of stellar parameters through asteroseismology 2019FrASS...6...41P
    A Hot Saturn Orbiting an Oscillating Late Subgiant Discovered by TESS 2019AJ....157..245H
    First detection of oscillations in the Halo giant HD 122563: Validation of seismic scaling relations and new parameters 2019A&A...625A..33C
    The Transiting Multi-planet System HD15337: Two Nearly Equal-mass Planets Straddling the Radius Gap 2019ApJ...876L..24G
    FliPerClass: In search of solar-like pulsators among TESS targets 2019A&A...624A..79B
    HD 219666 b: a hot-Neptune from TESS Sector 1 2019A&A...623A.165E
    A search for red giant solar-like oscillations in all Kepler data 2019MNRAS.485.5616H
    Detection and characterization of an ultra-dense sub-Neptunian planet orbiting the Sun-like star K2-292 2019A&A...623A.114L
    Oscillations in the Sun with SONG: Setting the scale for asteroseismic investigations 2019A&A...623L...9F
    Conducting the SONG: The Robotic Nature and Efficiency of a Fully Automated Telescope 2019PASP..131d5003F
    Asteroseismology of the Hyades red giant and planet host ɛ Tauri⋆ 2019A&A...622A.190A
    The Second APOKASC Catalog: The Empirical Approach 2018ApJS..239...32P
    Tools for Transit and Radial Velocity Modeling and Analysis 2018haex.bookE..13D
    Characterization of Exoplanets: Secondary Eclipses 2018haex.bookE..40A
    The Way to Circumbinary Planets 2018haex.bookE.115D
    Transit Photometry as an Exoplanet Discovery Method 2018haex.bookE.117D
    Impact of Exoplanet Science in the Early Twenty-First Century 2018haex.bookE.166D
    Planets, candidates, and binaries from the CoRoT/Exoplanet programme. The CoRoT transit catalogue 2018A&A...619A..97D
    Brown dwarf companion with a period of 4.6 yr interacting with the hot Jupiter CoRoT-20 b 2018A&A...619A.115R
    TESS's first planet. A super-Earth transiting the naked-eye star π Mensae 2018A&A...619L..10G
    FliPer: A global measure of power density to estimate surface gravities of main-sequence solar-like stars and red giants 2018A&A...620A..38B
    The Gaia-ESO Survey: properties of newly discovered Li-rich giants 2018A&A...617A...4S
    Non-linear seismic scaling relations 2018A&A...616A.104K
    The Kepler Follow-up Observation Program. II. Stellar Parameters from Medium- and High-resolution Spectroscopy 2018ApJ...861..149F
    Testing tidal theory for evolved stars by using red giant binaries observed by Kepler 2018MNRAS.479L.123B
    Oscillating red giants in eclipsing binary systems: empirical reference value for asteroseismic scaling relation 2018MNRAS.478.4669T
    HD 89345: a bright oscillating star hosting a transiting warm Saturn-sized planet observed by K2 2018MNRAS.478.4866V
    The envelope of the power spectra of over a thousand δ Scuti stars. The T̅eff - νmax scaling relation 2018A&A...614A..46B
    The mass and age of the first SONG target: the red giant 46 LMi 2018A&A...613A..53F
    Seismic probing of the first dredge-up event through the eccentric red-giant and red-giant spectroscopic binary KIC 9163796. How different are red-giant stars with a mass ratio of 1.015? 2018A&A...612A..22B
    Low-frequency photospheric and wind variability in the early-B supergiant HD 2905 2018A&A...612A..40S
    Frequency dependence of p-mode frequency shifts induced by magnetic activity in Kepler solar-like stars 2018A&A...611A..84S
    K2 photometry and HERMES spectroscopy of the blue supergiant ρ Leo: rotational wind modulation and low-frequency waves 2018MNRAS.476.1234A
    Non-grey dimming events of KIC 8462852 from GTC spectrophotometry 2018A&A...610L..12D
    The First Post-Kepler Brightness Dips of KIC 8462852 2018ApJ...853L...8B
    The Influence of Metallicity on Stellar Differential Rotation and Magnetic Activity 2018ApJ...852...46K
    Photospheric activity of the Sun with VIRGO and GOLF. Comparison with standard activity proxies 2017A&A...608A..87S
    Asteroseismic masses of retired planet-hosting A-stars using SONG 2017MNRAS.472.4110S
    Search for rings and satellites around the exoplanet CoRoT-9b using Spitzer photometry 2017A&A...603A.115L
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