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

    Improved characterization of the TOI-2141 system: A dense sub-Neptune with non-transiting inner and outer companions 2025A&A...704A.174L
    Glitch analysis and asteroseismic modelling of subgiant μ Herculis: confirming and interpreting the Γ<SUB>1</SUB> peak as the helium glitch 2025MNRAS.544.3428G
    Peakbagging the K2 KEYSTONE sample with PBJAM: characterizing the individual mode frequencies in solar-like oscillators 2025MNRAS.544.3247H
    Searching for Exoplanets Born Outside the Milky Way: VOYAGERS Survey Design 2025PASP..137k4404A
    An ultra-short period super-Earth and sub-Neptune spanning the Radius Valley orbiting the kinematic thick disc star TOI-2345 2025MNRAS.544.2614E
    TESS Subgiant and Lower-red-giant Asteroseismology in the Continuous Viewing Zones 2025ApJ...993...96G
    Six new doubly eclipsing quadruples in a 2+2 architecture 2025A&A...702A.234Z
    Two warm Earth-sized exoplanets and an Earth-sized candidate in the M5V-M6V binary system TOI-2267 2025A&A...702A..85Z
    Revisiting symbiotic binaries with interferometry: II. New PIONIER data 2025A&A...702A.151B
    Transit timing variations in HIP 41378: CHEOPS and TESS confirm a non-transiting sixth planet in the system 2025A&A...702A.211L
    Beyond the Nyquist frequency: Asteroseismic catalog of undersampled Kepler late subgiants and early red giants 2025A&A...702A.144L
    TOI-1438: A rare system with two short-period sub-Neptunes and a tentative long-period Jupiter-like planet orbiting a K0V star 2025A&A...702A..69P
    Luminaries in the sky: The TESS legacy sample of bright stars: I. Asteroseismic detections in naked-eye main-sequence and subgiant solar-like oscillators 2025A&A...701A.285L
    The CHEOPS view of HD 95338b: Refined transit parameters, and a search for exomoons 2025A&A...701A.240K
    The impact of rotation on the stochastic excitation of stellar acoustic modes in solar-like pulsators 2025A&A...700A..25B
    Asteroseismology of the G8 subgiant β Aquilae with SONG-Tenerife, SONG-Australia and TESS 2025A&A...700A..39K
    The KELT-7b atmospheric thermal-inversion conundrum revisited with CHEOPS, TESS, and additional data 2025A&A...700A...5G
    Abundances of P, S, and K in 58 bulge spheroid stars from APOGEE 2025A&A...700A.184B
    Non-transiting exoplanets as a means of understanding star–planet interactions in close-in systems 2025A&A...699A.226G
    The TOI-2427 system: Two close-in planets orbiting a late K-dwarf star 2025A&A...699A.185S
    CGCS 6306, another X-ray-emitting asymptotic giant branch star confirmed to be a symbiotic binary 2025A&A...699A.117M
    Dark skies of the slightly eccentric WASP-18 b from its optical-to-infrared dayside emission 2025A&A...699A.150D
    Symbiotic Stars in the Era of Modern Ground- and Space-Based Surveys 2025Galax..13...49M
    The local group symbiotic star population and its tenuous link with type Ia supernovae 2025A&A...698A.155L
    Structure and Dynamics of the Sun's Interior Revealed by the Helioseismic and Magnetic Imager 2025SoPh..300...70K
    V4141 Sgr: Outflows and repeated outbursts 2025A&A...698L...4M
    Red giant evolutionary status determination: The complete Kepler catalog 2025A&A...697A.165V
    Signature of spin-down stalling in stellar magnetic activity: The case of the open cluster NGC 6811 2025A&A...697A.177S
    Is the symbiotic recurrent nova T CrB late? Recent photometric evolution and comparison with past pre-outburst behaviour 2025MNRAS.541L..14M
    Precise radial velocities of giant stars: XVII. Distinguishing planets from intrinsically induced radial velocity signals in evolved stars 2025A&A...697A..32S
    Exploring the atmosphere of GJ 1132 b with CRIRES+ 2025A&A...697A..31P
    Kepler meets Gaia DR3: Homogeneous extinction-corrected color-magnitude diagram and binary classification 2025A&A...696A.243G
    The PLATO mission 2025ExA....59...26R
    Three new 2+2 quadruple systems with changing inclination 2025MNRAS.539.1015Z
    Improving the stellar age determination through joint modeling of binarity and asteroseismology: Grid modeling of the seismic red giant binary KIC 9163796 2025A&A...696A..42G
    Searching for hot water world candidates with CHEOPS: Refining the radii and analysing the internal structures and atmospheric lifetimes of TOI-238 b and TOI-1685 b 2025A&A...696A..28E
    A joint effort to discover and characterize two resonant mini-Neptunes around TOI-1803 with TESS, HARPS-N, and CHEOPS 2025A&A...695A.273Z
    TOI-2015 b: A sub-Neptune in strong gravitational interaction with an outer non-transiting planet 2025A&A...695A.281B
    Search for new Galactic Wolf–Rayet stars using Gaia DR3: I. Candidate selection and the follow-up of the bright sample 2025A&A...695A.227M
    Magnetic Activity Evolution of Solar-like Stars. II. S<SUB>ph</SUB>–Ro Evolution of Kepler Main-sequence Targets 2025ApJ...982..114M
    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