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

    The Seventeenth Data Release of the Sloan Digital Sky Surveys: Complete Release of MaNGA, MaStar, and APOGEE-2 Data 2022ApJS..259...35A
    The K2 Galactic Archaeology Program Data Release 3: Age-abundance Patterns in C1-C8 and C10-C18 2022ApJ...926..191Z
    Parameters of the eclipsing binary α Draconis observed by TESS and SONG 2022MNRAS.511.2648H
    TESS Giants Transiting Giants. II. The Hottest Jupiters Orbiting Evolved Stars 2022AJ....163..120G
    Study of chemically peculiar stars - I. High-resolution spectroscopy and K2 photometry of Am stars in the region of M44 2022MNRAS.510.5854J
    No swan song for Sun-as-a-star helioseismology: Performances of the Solar-SONG prototype for individual mode characterisation 2022A&A...658A..27B
    K2-99 revisited: a non-inflated warm Jupiter, and a temperate giant planet on a 522-d orbit around a subgiant 2022MNRAS.510.5035S
    A 20 Second Cadence View of Solar-type Stars and Their Planets with TESS: Asteroseismology of Solar Analogs and a Recharacterization of π Men c 2022AJ....163...79H
    Detections of solar-like oscillations in dwarfs and subgiants with Kepler DR25 short-cadence data 2022A&A...657A..31M
    Orbital period refinement of CoRoT planets with TESS observations 2021FrASS...8..210K
    GJ 367b: A dense, ultrashort-period sub-Earth planet transiting a nearby red dwarf star 2021Sci...374.1271L
    TOI-1431b/MASCARA-5b: A Highly Irradiated Ultrahot Jupiter Orbiting One of the Hottest and Brightest Known Exoplanet Host Stars 2021AJ....162..292A
    TESS Asteroseismology of α Mensae: Benchmark Ages for a G7 Dwarf and Its M Dwarf Companion 2021ApJ...922..229C
    Magnetic and Rotational Evolution of ρ CrB from Asteroseismology with TESS 2021ApJ...921..122M
    Asteroseismology of iota Draconis and Discovery of an Additional Long-period Companion 2021AJ....162..211H
    On the relation between active-region lifetimes and the autocorrelation function of light curves 2021MNRAS.508..267S
    37 new validated planets in overlapping K2 campaigns 2021MNRAS.508..195D
    Masses and compositions of three small planets orbiting the nearby M dwarf L231-32 (TOI-270) and the M dwarf radius valley 2021MNRAS.507.2154V
    Brightness Fluctuation Spectra of Sun-like Stars. I. The Mid-frequency Continuum 2021ApJ...916...66B
    A calibration of the Rossby number from asteroseismology 2021A&A...652L...2C
    Surface Rotation and Photometric Activity for Kepler Targets. II. G and F Main-sequence Stars and Cool Subgiant Stars 2021ApJS..255...17S
    TOI-220 b: a warm sub-Neptune discovered by TESS 2021MNRAS.505.3361H
    Hot planets around cool stars - two short-period mini-Neptunes transiting the late K-dwarf TOI-1260 2021MNRAS.505.4684G
    Magnetic signatures on mixed-mode frequencies. I. An axisymmetric fossil field inside the core of red giants 2021A&A...650A..53B
    Weighing stars from birth to death: mass determination methods across the HRD 2021A&ARv..29....4S
    A transmission spectrum of the planet candidate WD 1856+534 b and a lower limit to its mass 2021A&A...649A.131A
    Spectroscopic and seismic analysis of red giants in eclipsing binaries discovered by Kepler 2021A&A...648A.113B
    ROOSTER: a machine-learning analysis tool for Kepler stellar rotation periods 2021A&A...647A.125B
    Precise radial velocities of giant stars. XV. Mysterious nearly periodic radial velocity variations in the eccentric binary ε Cygni 2021A&A...647A.160H
    Probing the internal magnetism of stars using asymptotic magneto-asteroseismology 2021A&A...647A.122M
    TOI-257b (HD 19916b): a warm sub-saturn orbiting an evolved F-type star 2021MNRAS.502.3704A
    Observing the changing surface structures of the active K giant σ Geminorum with SONG 2021A&A...646A...6K
    Search for flares and associated CMEs on late-type main-sequence stars in optical SDSS spectra 2021A&A...646A..34K
    Prospects for Galactic and stellar astrophysics with asteroseismology of giant stars in the TESS continuous viewing zones and beyond 2021MNRAS.502.1947M
    An Intermediate-age Alpha-rich Galactic Population in K2 2021AJ....161..100W
    A planetary system with two transiting mini-Neptunes near the radius valley transition around the bright M dwarf TOI-776 2021A&A...645A..41L
    A Modified Kwee─Van Woerden Method for Eclipse Minimum Timing with Reliable Error Estimates 2020Galax...9....1D
    The Occurrence of Rocky Habitable-zone Planets around Solar-like Stars from Kepler Data 2021AJ....161...36B
    Properties of the Hyades, the eclipsing binary HD 27130, and the oscillating red giant ∊ Tauri 2021A&A...645A..25B
    Maintaining the Ephemeris of 20 CoRoT Planets: Transit Minimum Times and Potential Transit Timing Variations 2020JAVSO..48..201D
    Related projects
    Componentes del experimento PLATO
    PLATO (PLAnetary Transits and Oscillations of stars)
    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
    Hans Jörg
    Deeg Deeg