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, 3) to search for extrasolar planets using photometric methods (primarily by transits of their host stars) and their characterization (using radial velocity information) and 4) the study of the planetary atmospheres.

    To reach our first objective, we use Global Helioseismology (analysis of the solar oscillation eigenmodes) and Local Helioseismology (that uses travel waves). Solar seismology allows to accurately infer information about the internal structure and dynamics of the Sun,. This project covers the various necessary aspects to attain the aforementioned objectives: instrumental, observational, reduction, analysis and interpretation of data and, finally, theoretical developments of inversion techniques and development of structure and evolution models.

    On the other hand, the Astroseismology aims to obtain a similar knowledge of other stars. Thanks to the huge number of stars observed by CoRoT, Kepler and TESS space missions it is possible to extract seismic global parameters of hundreds of stars; both solar type and red giants. Furthermore, the recent deployment and beginning of observations with the high precision spectrographs of the SONG (Stellar Observations Network Group) ground-based telescopes will substantially improve the characterization of the eigenmodes spectrum in bright stars.

    The strategy of using planetary transits to discover new planets around other stars consists of the photometric detection of the dimming of the light of the star when one of its planets passes, or ‘transits’ in front of it. Currently this method is the preferred one for the study of small planets, not only due to its sensitivity, but also because this method allows a more detailed investigation of the planets found (e.g. Planetary atmospheres). This technique is similar to the one that is used for helio- and asteroseismology and so some of its methods are a logical extension from that. However, it is also important to develop new algorithms and observing methods for the unequivocal detection and analysis of planets and to be able to distinguish them from false alarms.

    The current horizon for studies of exoplanets with space missions involves new missions, beginning with the launch of CHEOPS, followed by TESS, JWST and in 2026, PLATO. Thus, there is presently a window of opportunity for ground-based facilities, and we are pursuing observations using mainly TNG, NOT y GTC.

    Principal investigator

    Milestones

    1. Members of the team (P. G. Beck, H. Deeg, S. Mathur, F. H. Perez, C. Regulo) were involved in the discovery and characterization of a warm Saturn transiting a slightly evolved solar-like star (HD 89345) observed with the NASA K2 mission and confirmed with RV measurements. The seismic analysis of the star led to precise estimates of the stellar parameters.
    2. P.G.Beck lead two papers on binary systems hosting red-giant binaries, using asteroseismic techniques and data from the Kepler space telescope. Beck et al (2018a,b) allow a better understanding of the stellar structure of the stellar components, and the tidal interaction in binary systems. The internal mixing was investigated through measurements lithium.
    3. S. Mathur participated in the analysis of the first planet discovered with the NASA TESS mission, orbiting the star Pi Men. The seismic analysis led to a very marginal detection but gave a hint of the asteroseismic potential with the TESS data (Gandolfi et al. 2018).
    4. Project "Solar-SONG". For the first time, stellar instrumentation (SONG spectrograph) has been used to obtain precise measurements of the radial velocity of the Sun with high temporal cadence (4 sec.) and long duration (57 consecutive days) to allow the detailed study of the spectrum of oscillations ( p-modes) and obtain their global parameters
    5. The researchers Hans J. Deeg and Juan Antonio Belmonte coordinated the edition of the "Handbook of Exoplanets", four volumes with 160 articles by more than 300 specialists in exoplanetology. Three years of intensive work have resulted in a complete documentation on the state of the art of the studies of the planets beyond the Solar System.

    Related publications

    • An eclipsing substellar binary in a young triple system discovered by SPECULOOS
      Mass, radius and age are three of the most fundamental parameters for celestial objects, enabling insight into the evolution and internal physics of stars, brown dwarfs and planets. Brown dwarfs are hydrogen-rich objects that are unable to sustain core fusion reactions but are supported against collapse by electron degeneracy pressure 1. As they
      Triaud, Amaury H. M. J. et al.

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      3
      2020
      Citations
      32
    • The 16th Data Release of the Sloan Digital Sky Surveys: First Release from the APOGEE-2 Southern Survey and Full Release of eBOSS Spectra
      This paper documents the 16th data release (DR16) from the Sloan Digital Sky Surveys (SDSS), the fourth and penultimate from the fourth phase (SDSS-IV). This is the first release of data from the Southern Hemisphere survey of the Apache Point Observatory Galactic Evolution Experiment 2 (APOGEE-2); new data from APOGEE-2 North are also included
      Ahumada, Romina et al.

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      7
      2020
      Citations
      1000
    • The CARMENES search for exoplanets around M dwarfs. A super-Earth planet orbiting HD 79211 (GJ 338 B)
      Aims: We report on radial velocity time series for two M0.0 V stars, GJ 338 B and GJ 338 A, using the CARMENES spectrograph, complemented by ground-telescope photometry from Las Cumbres and Sierra Nevada observatories. We aim to explore the presence of small planets in tight orbits using the spectroscopic radial velocity technique. Methods: We
      González-Álvarez, E. et al.

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      5
      2020
      Citations
      16
    • Spectroscopic and Asteroseismic Analysis of the Secondary Clump Red Giant HD 226808
      In order to clarify the properties of the secondary clump star HD 226808 (KIC 5307747), we combined four years of data from Kepler space photometry with high-resolution spectroscopy of the High Efficiency and Resolution Mercator Échelle Spectrograph mounted on the Mercator telescope. The fundamental atmospheric parameters, radial velocities
      De Moura, Bruno Lustosa et al.

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      5
      2020
      Citations
      1
    • Doppler Imaging and Differential Rotation of σ<SUP>2</SUP> Coronae Borealis Using SONG
      We present new Doppler images of both components of the double-lined binary σ 2 CrB, based on the high-resolution spectroscopic data collected during 11 nights in 2015 March-April. The observed spectra form two independent data sets with sufficient phase coverage. We apply the least-squares deconvolution to all observed spectra to obtain high
      Xiang, Yue et al.

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      4
      2020
      Citations
      5
    • Three planets transiting the evolved star EPIC 249893012: a hot 8.8-M<SUB>⊕</SUB> super-Earth and two warm 14.7 and 10.2-M<SUB>⊕</SUB> sub-Neptunes
      We report the discovery of a new planetary system with three transiting planets, one super-Earth and two sub-Neptunes, that orbit EPIC 249893012, a G8 IV-V evolved star (M ⋆ = 1.05 ± 0.05 M ☉, R ⋆ = 1.71 ± 0.04 R ☉, T eff = 5430 ± 85 K). The star is just leaving the main sequence. We combined K2 photometry with IRCS adaptive-optics imaging and
      Hidalgo, D. et al.

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      4
      2020
      Citations
      19
    • TOI-503: The First Known Brown-dwarf Am-star Binary from the TESS Mission
      We report the discovery of an intermediate-mass transiting brown dwarf (BD), TOI-503b, from the TESS mission. TOI-503b is the first BD discovered by TESS, and it has circular orbit around a metallic-line A-type star with a period of P = 3.6772 ± 0.0001 days. The light curve from TESS indicates that TOI-503b transits its host star in a grazing
      Šubjak, Ján et al.

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      4
      2020
      Citations
      41
    • Age dating of an early Milky Way merger via asteroseismology of the naked-eye star ν Indi
      Over the course of its history, the Milky Way has ingested multiple smaller satellite galaxies 1. Although these accreted stellar populations can be forensically identified as kinematically distinct structures within the Galaxy, it is difficult in general to date precisely the age at which any one merger occurred. Recent results have revealed a
      Chaplin, William J. et al.

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      1
      2020
      Citations
      59
    • TESS Spots a Hot Jupiter with an Inner Transiting Neptune
      Hot Jupiters are rarely accompanied by other planets within a factor of a few in orbital distance. Previously, only two such systems have been found. Here, we report the discovery of a third system using data from the Transiting Exoplanet Survey Satellite (TESS). The host star, TOI-1130, is an eleventh magnitude K-dwarf in Gaia G-band. It has two
      Huang, Chelsea X. et al.

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      3
      2020
      Citations
      52
    • Transiting exoplanets from the CoRoT space mission. XXIX. The hot Jupiters CoRoT-30 b and CoRoT-31 b
      Aims: We report the discovery as well as the orbital and physical characterizations of two new transiting giant exoplanets, CoRoT-30 b and CoRoT-31 b, with the CoRoT space telescope. Methods: We analyzed two complementary data sets: photometric transit light curves measured by CoRoT, and radial velocity curves measured by the HARPS spectrometer. To
      Bordé, P. et al.

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      3
      2020
      Citations
      3
    • TOI-132 b: A short-period planet in the Neptune desert transiting a V = 11.3 G-type star<SUP>★</SUP>
      The Neptune desert is a feature seen in the radius-period plane, whereby a notable dearth of short period, Neptune-like planets is found. Here, we report the Transiting Exoplanet Survey Satellite (TESS) discovery of a new short-period planet in the Neptune desert, orbiting the G-type dwarf TYC 8003-1117-1 (TOI-132). TESS photometry shows transit
      Díaz, Matías R. et al.

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      3
      2020
      Citations
      22
    • It Takes Two Planets in Resonance to Tango around K2-146
      K2-146 is a cool, 0.358 ${M}_{\odot }$ dwarf that was found to host a mini-Neptune with a 2.67 day period. The planet exhibited strong transit timing variations (TTVs) of greater than 30 minutes, indicative of the presence of an additional object in the system. Here we report the discovery of the previously undetected outer planet in the system, K2
      Lam, Kristine W. F. et al.

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      3
      2020
      Citations
      16
    • Mass determinations of the three mini-Neptunes transiting TOI-125
      The Transiting Exoplanet Survey Satellite, TESS, is currently carrying out an all-sky search for small planets transiting bright stars. In the first year of the TESS survey, a steady progress was made in achieving the mission's primary science goal of establishing bulk densities for 50 planets smaller than Neptune. During that year, the TESS's
      Nielsen, L. D. et al.

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      3
      2020
      Citations
      33
    • Detection and Characterization of Oscillating Red Giants: First Results from the TESS Satellite
      Since the onset of the "space revolution" of high-precision high-cadence photometry, asteroseismology has been demonstrated as a powerful tool for informing Galactic archeology investigations. The launch of the NASA Transiting Exoplanet Survey Satellite (TESS) mission has enabled seismic-based inferences to go full sky—providing a clear advantage
      Aguirre, Víctor Silva et al.

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      2
      2020
      Citations
      0
    • Measurement of Atmospheric Scintillation during a Period of Saharan Dust (Calima) at Observatorio del Teide, Iz̃ana, Tenerife, and the Impact on Photometric Exposure Times
      We present scintillation noise profiles captured at the Observatorio del Teide, Izaña, Tenerife, over a one-week period in 2017 September. Contemporaneous data from the Birmingham Solar Oscillations Network (BiSON) and the Stellar Activity (STELLA) robotic telescopes provides estimates of daily atmospheric extinction allowing the scintillation
      Hale, S. J. et al.

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      3
      2020
      Citations
      5
    • Chemical Evolution in the Milky Way: Rotation-based Ages for APOGEE-Kepler Cool Dwarf Stars
      We use models of stellar angular momentum evolution to determine ages for ∼500 stars in the APOGEE-Kepler Cool Dwarfs sample. We focus on lower-main-sequence stars, where other age-dating tools become ineffective. Our age distributions are compared to those derived from asteroseismic and giant samples and solar analogs. We are able to recover
      Claytor, Zachary R. et al.

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      1
      2020
      Citations
      45
    • Core─Envelope Coupling in Intermediate-mass Core-helium Burning Stars
      Stars between two and three solar masses rotate rapidly on the main sequence, and the detection of slow core and surface rotation in the core-helium burning phase for these stars places strong constraints on their angular momentum transport and loss. From a detailed asteroseismic study of the mixed-dipole mode pattern in a carefully selected
      Tayar, Jamie et al.

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      12
      2019
      Citations
      23
    • TESS Asteroseismology of the Known Red-giant Host Stars HD 212771 and HD 203949
      The Transiting Exoplanet Survey Satellite (TESS) is performing a near all-sky survey for planets that transit bright stars. In addition, its excellent photometric precision enables asteroseismology of solar-type and red-giant stars, which exhibit convection-driven, solar-like oscillations. Simulations predict that TESS will detect solar-like
      Campante, Tiago L. et al.

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      11
      2019
      Citations
      38
    • Surface Rotation and Photometric Activity for Kepler Targets. I. M and K Main-sequence Stars
      Brightness variations due to dark spots on the stellar surface encode information about stellar surface rotation and magnetic activity. In this work, we analyze the Kepler long-cadence data of 26,521 main-sequence stars of spectral types M and K in order to measure their surface rotation and photometric activity level. Rotation-period estimates are
      Santos, A. R. G. et al.

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      9
      2019
      Citations
      108
    • Signatures of Magnetic Activity: On the Relation between Stellar Properties and p-mode Frequency Variations
      In the Sun, the properties of acoustic modes are sensitive to changes in the magnetic activity. In particular, mode frequencies are observed to increase with increasing activity level. Thanks to CoRoT and Kepler, such variations have been found in other solar-type stars and encode information on the activity-related changes in their interiors. Thus
      Santos, A. R. G. et al.

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      9
      2019
      Citations
      13

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