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

    Asymmetry in the atmosphere of the ultra-hot Jupiter WASP-76 b 2024A&A...684A..27D
    Planets observed with CHEOPS. Two super-Earths orbiting the red dwarf star TOI-776 2024A&A...684A..12F
    Predicted asteroseismic detection yield for solar-like oscillating stars with PLATO 2024A&A...683A..78G
    Accretion-induced flickering variability among symbiotic stars from space photometry with NASA TESS 2024A&A...683A..84M
    TOI-544 b: a potential water-world inside the radius valley in a two-planet system 2024MNRAS.52711138O
    Ground-based photometric follow-up for exoplanet detections with the PLATO mission 2024CoSka..54b.142D
    CHEOPS observations of KELT-20 b/MASCARA-2 b: An aligned orbit and signs of variability from a reflective day side 2024A&A...683A...1S
    The EBLM Project- XI. Mass, radius, and effective temperature measurements for 23 M-dwarf companions to solar-type stars observed with CHEOPS 2024MNRAS.528.5703S
    Constraining the reflective properties of WASP-178 b using CHEOPS photometry 2024A&A...682A.102P
    Spectroscopic identification of rapidly rotating red giant stars in APOKASC-3 and APOGEE DR16 2024MNRAS.528.3232P
    Characterising TOI-732 b and c: New insights into the M-dwarf radius and density valley 2024A&A...682A..66B
    Constraining stellar and orbital co-evolution through ensemble seismology of solar-like oscillators in binary systems. A census of oscillating red giants and dwarf stars in Gaia DR3 binaries 2024A&A...682A...7B
    The APO-K2 Catalog. I. 7500 Red Giants with Fundamental Stellar Parameters from APOGEE DR17 Spectroscopy and K2-GAP Asteroseismology 2024AJ....167...50S
    Seismic and spectroscopic analysis of nine bright red giants observed by Kepler 2024MNRAS.527.8535C
    No random transits in CHEOPS observations of HD 139139 2023A&A...680A..78A
    In search of gravity mode signatures in main sequence solar-type stars observed by Kepler 2023A&A...679A.104B
    Stellar spectral-type (mass) dependence of the dearth of close-in planets around fast-rotating stars. Architecture of Kepler confirmed single-exoplanet systems compared to star-planet evolution models 2023A&A...679L..12G
    A resonant sextuplet of sub-Neptunes transiting the bright star HD 110067 2023Natur.623..932L
    CHEOPS and TESS view of the ultra-short-period super-Earth TOI-561 b 2023A&A...679A..92P
    Refining the properties of the TOI-178 system with CHEOPS and TESS 2023A&A...678A.200D
    Asteroseismology and Spectropolarimetry of the Exoplanet Host Star λ Serpentis 2023AJ....166..167M
    A 5M<SUB>Jup</SUB> non-transiting coplanar circumbinary planet around Kepler-1660AB 2023MNRAS.525.4628G
    Investigating the visible phase-curve variability of 55 Cnc e★ 2023A&A...677A.112M
    Company for the Ultra-high Density, Ultra-short Period Sub-Earth GJ 367 b: Discovery of Two Additional Low-mass Planets at 11.5 and 34 Days 2023ApJ...955L...3G
    TOI-2084 b and TOI-4184 b: Two new sub-Neptunes around M dwarf stars 2023A&A...677A..38B
    TOI-1416: A system with a super-Earth planet with a 1.07 d period 2023A&A...677A..12D
    Everything that glitters is not gold: V1315 Cas is not a dormant black hole 2023MNRAS.524.5749Z
    TOI-1130: A photodynamical analysis of a hot Jupiter in resonance with an inner low-mass planet 2023A&A...675A.115K
    Unresolved Rossby and gravity modes in 214 A and F stars showing rotational modulation 2023MNRAS.524.4196H
    Magnetic Activity Evolution of Solar-like Stars. I. S <SUB>ph</SUB>-Age Relation Derived from Kepler Observations 2023ApJ...952..131M
    The planetary system around HD 190622 (TOI-1054). Measuring the gas content of low-mass planets orbiting F-stars 2023A&A...675A.183C
    Solar-like oscillations in γ Cephei A as seen through SONG and TESS. A seismic study of γ Cephei A 2023A&A...675A.197K
    FX UMa: A New Heartbeat Binary System with Linear and Nonlinear Tidal Oscillations and δ Sct Pulsations 2023AJ....166...42W
    The breakdown of current gyrochronology as evidenced by old coeval stars 2023MNRAS.523.5947S
    Pyodine: an open, flexible reduction software for iodine-calibrated precise radial velocities 2023A&A...674A.164H
    TOI-733 b: A planet in the small-planet radius valley orbiting a Sun-like star 2023A&A...674A.117G
    Multi-campaign asteroseismic analysis of eight solar-like pulsating stars observed by the K2 mission 2023A&A...674A.106G
    TOI-5678b: A 48-day transiting Neptune-mass planet characterized with CHEOPS and HARPS★ 2023A&A...674A..43U
    Refined parameters of the HD 22946 planetary system and the true orbital period of planet d★ 2023A&A...674A..44G
    TESS and CHEOPS discover two warm sub-Neptunes transiting the bright K-dwarf HD 15906 2023MNRAS.523.3090T
    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