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

    Transit timing analysis of CoRoT-1b 2010A&A...510A..94C
    The thermal emission of the young and massive planet CoRoT-2b at 4.5 and 8 μm 2010A&A...511A...3G
    The secondary eclipse of CoRoT-1b 2009A&A...506..353A
    The SARS algorithm: detrending CoRoT light curves with Sysrem using simultaneous external parameters 2010MNRAS.404L..99O
    The Orbital Phases and Secondary Transits of Kepler-10b. A Physical Interpretation Based on the Lava-ocean Planet Model 2011ApJ...741L..30R
    The Mass of CoRoT-7b 2011ApJ...743...75H
    Removing systematics from the CoRoT light curves. I. Magnitude-dependent zero point 2009A&A...506..431M
    Rate and nature of false positives in the CoRoT exoplanet search 2009A&A...506..337A
    Possible detection of phase changes from the non-transiting planet HD 46375b by CoRoT 2010A&A...518L.153G
    Planetary transit candidates in the CoRoT-SRc01 field 2012A&A...539A..14E
    Planetary transit candidates in the CoRoT LRa01 field 2012A&A...538A.112C
    Planetary transit candidates in the CoRoT initial run: resolving their nature 2009A&A...506..321M
    Planetary transit candidates in CoRoT-LRc01 field 2009A&A...506..501C
    Planetary transit candidates in Corot-IRa01 field 2009A&A...506..491C
    Noise properties of the CoRoT data. A planet-finding perspective 2009A&A...506..425A
    Ground-based photometry of space-based transit detections: photometric follow-up of the CoRoT  mission 2009A&A...506..343D
    Ground-based Near-infrared Observations of the Secondary Eclipse of CoRoT-2b 2010AJ....139.1481A
    Extrasolar planet detection by binary stellar eclipse timing: evidence for a third body around CM Draconis 2008A&A...480..563D
    Exoplanet discoveries with the CoRoT space observatory 2010SoSyR..44..520L
    Exo-Dat: An Information System in Support of the CoRoT/Exoplanet Science 2009AJ....138..649D
    CoRoT LRa02_E2_0121: Neptune-size planet candidate turns into a hierarchical triple system with a giant primary 2011A&A...534A..67T
    A transiting giant planet with a temperature between 250K and 430K 2010Natur.464..384D
    CoRoT Measures Solar-Like Oscillations and Granulation in Stars Hotter Than the Sun 2008Sci...322..558M
    Preliminary results on the contribution of the convection motions to the Doppler velocity signal 2008JPhCS.118a2089S
    Infrared astronomical characteristics of the Roque de los Muchachos Observatory: precipitable water vapour statistics 2010MNRAS.405.2683G
    Ground-based Multisite Observations of Two Transits of HD 80606b 2010ApJ...722..880S
    Limits to the planet candidate GJ 436c 2008A&A...487L...5A
    TrES-5: A Massive Jupiter-sized Planet Transiting a Cool G Dwarf 2011ApJ...741..114M
    Transit timing analysis of the exoplanets TrES-1 and TrES-2 2009A&A...508.1011R
    SYMPA, a dedicated instrument for Jovian seismology. II. Real performance and first results 2008A&A...490..859G
    Detection of transit timing variations in excess of one hour in the Kepler multi-planet candidate system KOI 806 with the GTC 2011A&A...536L...9T
    Constraints of a pulsation frequency on stellar parameters in the eclipsing spectroscopic binary system V577 Oph 2010AN....331..952C
    Constraining the Properties of Delta Scuti Stars Using Spectroscopic Eclipsing Binary Systems 2011ApJ...733...38C
    An eclipsing post-common-envelope binary in the field of the Kepler mission 2012MNRAS.420.3017A
    A New Spectroscopic and Photometric Analysis of the Transiting Planet Systems TrES-3 and TrES-4 2009ApJ...691.1145S
    A cool starspot or a second transiting planet in the TrES-1 system? 2009A&A...494..391R
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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