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

    Two warm Neptunes transiting HIP 9618 revealed by TESS and Cheops 2023MNRAS.523.3069O
    A new dynamical modeling of the WASP-47 system with CHEOPS observations 2023A&A...673A..42N
    Revisiting the Red Giant Branch Hosts KOI-3886 and ι Draconis. Detailed Asteroseismic Modeling and Consolidated Stellar Parameters 2023AJ....165..214C
    Temporal variation of the photometric magnetic activity for the Sun and Kepler solar-like stars 2023A&A...672A..56S
    A super-Earth and a mini-Neptune near the 2:1 MMR straddling the radius valley around the nearby mid-M dwarf TOI-2096 2023A&A...672A..70P
    The geometric albedo of the hot Jupiter HD 189733b measured with CHEOPS 2023A&A...672A..24K
    Glancing through the debris disk: Photometric analysis of DE Boo with CHEOPS 2023A&A...671A.127B
    A full transit of v<SUP>2</SUP> Lupi d and the search for an exomoon in its Hill sphere with CHEOPS 2023A&A...671A.154E
    TOI-836: A super-Earth and mini-Neptune transiting a nearby K-dwarf 2023MNRAS.520.3649H
    TOI-1055 b: Neptunian planet characterised with HARPS, TESS, and CHEOPS 2023A&A...671L...8B
    Hint of an exocomet transit in the CHEOPS light curve of HD 172555 2023A&A...671A..25K
    TESS Asteroseismic Analysis of HD 76920: The Giant Star Hosting an Extremely Eccentric Exoplanet 2023ApJ...945...20J
    Rotational modulation in A and F stars: magnetic stellar spots or convective core rotation? 2023MNRAS.520..216H
    Connecting photometric and spectroscopic granulation signals with CHEOPS and ESPRESSO 2023A&A...670A..24S
    Examining the orbital decay targets KELT-9 b, KELT-16 b, and WASP-4b, and the transit-timing variations of HD 97658 b 2023A&A...669A.124H
    Radial velocity confirmation of a hot super-Neptune discovered by TESS with a warm Saturn-mass companion 2023MNRAS.519.5637K
    55 Cancri e's occultation captured with CHEOPS 2023A&A...669A..64D
    The EBLM project - IX. Five fully convective M-dwarfs, precisely measured with CHEOPS and TESS light curves 2023MNRAS.519.3546S
    Discovery of TOI-1260d and the characterization of the multiplanet system 2023MNRAS.519.1437L
    HD 20329b: An ultra-short-period planet around a solar-type star found by TESS 2022A&A...668A.158M
    On the Characterization of GJ 504: A Magnetically Active Planet-host Star Observed by the Transiting Exoplanet Survey Satellite (TESS) 2022ApJ...940...93D
    Spinning up the Surface: Evidence for Planetary Engulfment or Unexpected Angular Momentum Transport? 2022ApJ...940...23T
    Hunting for anti-solar differentially rotating stars using the Rossby number. An application to the Kepler field 2022A&A...667A..50N
    TOI-2196 b: Rare planet in the hot Neptune desert transiting a G-type star 2022A&A...666A.184P
    Precise mass determination for the keystone sub-Neptune planet transiting the mid-type M dwarf G 9-40 2022A&A...666A.154L
    Confirmation and characterisation of three giant planets detected by TESS from the FIES/NOT and Tull/McDonald spectrographs 2022A&A...667A..22K
    99 oscillating red-giant stars in binary systems with NASA TESS and NASA Kepler identified from the SB9-Catalogue 2022A&A...667A..31B
    A 4 Gyr M-dwarf Gyrochrone from CFHT/MegaPrime Monitoring of the Open Cluster M67 2022ApJ...938..118D
    SPECULOOS Northern Observatory: Searching for Red Worlds in the Northern Skies 2022PASP..134j5001B
    Solar-like oscillations and ellipsoidal variations in TESS observations of the binary 12 Boötis 2022MNRAS.516.3709B
    Sub-stellar companions of intermediate-mass stars with CoRoT: CoRoT-34b, CoRoT-35b, and CoRoT-36b 2022MNRAS.516..636S
    The Origin of Weakened Magnetic Braking in Old Solar Analogs 2022ApJ...933L..17M
    Magnetic activities on two single-lined RS Canum Venaticorum binaries IM Pegasi and σ Geminorum 2022MNRAS.514.4190C
    A low-eccentricity migration pathway for a 13-h-period Earth analogue in a four-planet system 2022NatAs...6..736S
    The young HD 73583 (TOI-560) planetary system: two 10-M<SUB>⊕</SUB> mini-Neptunes transiting a 500-Myr-old, bright, and active K dwarf 2022MNRAS.514.1606B
    TOI-2046b, TOI-1181b, and TOI-1516b, three new hot Jupiters from TESS: planets orbiting a young star, a subgiant, and a normal star 2022MNRAS.513.5955K
    The TESS-Keck Survey. XI. Mass Measurements for Four Transiting Sub-Neptunes Orbiting K Dwarf TOI-1246 2022AJ....163..293T
    TOI-1670 b and c: An Inner Sub-Neptune with an Outer Warm Jupiter Unlikely to Have Originated from High-eccentricity Migration 2022AJ....163..225T
    A Radial Velocity Study of the Planetary System of π Mensae: Improved Planet Parameters for π Mensae c and a Third Planet on a 125 Day Orbit 2022AJ....163..223H
    TESS asteroseismology of the Kepler red giants 2022MNRAS.512.1677S
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    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