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

    Asymptotic g modes: Evidence for a rapid rotation of the solar core 2017A&A...604A..40F
    Atmospheric Extinction Coefficients in the Ic Band for Several Major International Observatories: Results from the BiSON Telescopes, 1984-2016 2017AJ....154...89H
    On the signatures of flare-induced global waves in the Sun: GOLF and VIRGO observations 2017MNRAS.471.4677K
    A deeper view of the CoRoT-9 planetary system. A small non-zero eccentricity for CoRoT-9b likely generated by planet-planet scattering 2017A&A...603A..43B
    Limits to the presence of transiting circumbinary planets in CoRoT Data 2017A&A...602A.117K
    Evidence of chaotic modes in the analysis of four δ Scuti stars 2017A&A...601A..57B
    Kepler observations of the asteroseismic binary HD 176465 2017A&A...601A..82W
    Kepler sheds new and unprecedented light on the variability of a blue supergiant: Gravity waves in the O9.5Iab star HD 188209 2017A&A...602A..32A
    Internal rotation of 13 low-mass low-luminosity red giants in the Kepler field 2017A&A...602A..62T
    CoRoT 223992193: Investigating the variability in a low-mass, pre-main sequence eclipsing binary with evidence of a circumbinary disk 2017A&A...599A..27G
    First Results from the Hertzsprung SONG Telescope: Asteroseismology of the G5 Subgiant Star μ Herculis 2017ApJ...836..142G
    TEE, an estimator for the precision of eclipse and transit minimum times 2017A&A...599A..93D
    Asteroseismology of Solar-Type Stars with K2: Detection of Oscillations in C1 Data 2015PASP..127.1038C
    Transiting exoplanets from the CoRoT space mission⋆. XXVIII. CoRoT-33b, an object in the brown dwarf desert with 2:3 commensurability with its host star 2015A&A...584A..13C
    HD 144548: A young triply eclipsing system in the Upper Scorpius OB association 2015A&A...584L...8A
    Analysis of the acoustic cut-off frequency and high-frequency peaks in six Kepler stars with stochastically excited pulsations 2015A&A...583A..74J
    A seismic and gravitationally bound double star observed by Kepler. Implication for the presence of a convective core 2015A&A...582A..25A
    Evidence of amplitude modulation due to resonant mode coupling in the δ Scuti star KIC 5892969. A particular or a general case? 2015A&A...579A.133B
    Transiting exoplanets from the CoRoT space mission. XXVII. CoRoT-28b, a planet orbiting an evolved star, and CoRoT-29b, a planet showing an asymmetric transit 2015A&A...579A..36C
    Period, epoch, and prediction errors of ephemerides from continuous sets of timing measurements 2015A&A...578A..17D
    Kepler-423b: a half-Jupiter mass planet transiting a very old solar-like star 2015A&A...576A..11G
    The two-colour EMCCD instrument for the Danish 1.54 m telescope and SONG 2015A&A...574A..54S
    Kepler-432 b: a massive warm Jupiter in a 52-day eccentric orbit transiting a giant star 2015A&A...573L...6O
    The PLATO 1.0 mission 2014ExA....38..249R
    Rotation and magnetism of Kepler pulsating solar-like stars. Towards asteroseismically calibrated age-rotation relations 2014A&A...572A..34G
    Reconstruction of global solar radiation time series from 1933 to 2013 at the Izaña Atmospheric Observatory 2014AMT.....7.3139G
    CoRoT-22 b: a validated 4.9 R⊕ exoplanet in 10-d orbit 2014MNRAS.444.2783M
    Revisiting the transits of CoRoT-7b at a lower activity level 2014A&A...569A..74B
    Investigating magnetic activity of F stars with the Kepler mission 2014IAUS..302..222M
    Transiting exoplanets from the CoRoT space mission. XXVI. CoRoT-24: a transiting multiplanet system 2014A&A...567A.112A
    Impact on asteroseismic analyses of regular gaps in Kepler data 2014A&A...568A..10G
    The Mark-I helioseismic experiment - I. Measurements of the solar gravitational redshift (1976-2013) 2014MNRAS.443.1837R
    Confirmation of an exoplanet using the transit color signature: Kepler-418b, a blended giant planet in a multiplanet system 2014A&A...567A..14T
    Oscillation mode linewidths and heights of 23 main-sequence stars observed by Kepler 2014A&A...566A..20A
    Recovering Long-term Aerosol Optical Depth Series (1976-2012) from an Astronomical Potassium-based Resonance Scattering Spectrometer 2014AMTD....7.4093B
    Re-construction of global solar radiation time series from 1933 to 2013 at the Izaña Atmospheric Observatory 2014AMTD....7.4191G
    Seismic analysis of HD 43587Aa, a solar-like oscillator in a multiple system 2014A&A...564A..34B
    Seismic constraints on the radial dependence of the internal rotation profiles of six Kepler subgiants and young red giants 2014A&A...564A..27D
    Study of KIC 8561221 observed by Kepler: an early red giant showing depressed dipolar modes 2014A&A...563A..84G
    Stellar Observations Network Group: The prototype is nearly ready 2014IAUS..301...69G
    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