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

    • Examining the orbital decay targets KELT-9 b, KELT-16 b, and WASP-4b, and the transit-timing variations of HD 97658 b

      Context. Tidal orbital decay is suspected to occur for hot Jupiters in particular, with the only observationally confirmed case of this being WASP-12b. By examining this effect, information on the properties of the host star can be obtained using the so-called stellar modified tidal quality factor Q*', which describes the efficiency with which the

      Harre, J. -V. et al.

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      1
      2023
      Citations
      6
    • Radial velocity confirmation of a hot super-Neptune discovered by TESS with a warm Saturn-mass companion

      We report the discovery and confirmation of the planetary system TOI-1288. This late G dwarf harbours two planets: TOI-1288 b and TOI-1288 c. We combine TESS space-borne and ground-based transit photometry with HARPS-N and HIRES high-precision Doppler measurements, which we use to constrain the masses of both planets in the system and the radius of

      Knudstrup, E. et al.

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      3
      2023
      Citations
      1
    • 55 Cancri e's occultation captured with CHEOPS

      Past occultation and phase-curve observations of the ultra-short period super-Earth 55 Cnc e obtained at visible and infrared wavelengths have been challenging to reconcile with a planetary reflection and emission model. In this study, we analyse a set of 41 occultations obtained over a two-year timespan with the CHEOPS satellite. We report the

      Demory, B. -O. et al.

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      1
      2023
      Citations
      5
    • The EBLM project - IX. Five fully convective M-dwarfs, precisely measured with CHEOPS and TESS light curves

      Eclipsing binaries are important benchmark objects to test and calibrate stellar structure and evolution models. This is especially true for binaries with a fully convective M-dwarf component for which direct measurements of these stars' masses and radii are difficult using other techniques. Within the potential of M-dwarfs to be exoplanet host

      Sebastian, D. et al.

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      3
      2023
      Citations
      5
    • Discovery of TOI-1260d and the characterization of the multiplanet system

      We report the discovery of a third planet transiting the star TOI-1260, previously known to host two transiting sub-Neptune planets with orbital periods of 3.127 and 7.493 d, respectively. The nature of the third transiting planet with a 16.6-d orbit is supported by ground-based follow-up observations, including time-series photometry, high-angular

      Lam, K. W. F. et al.

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      2
      2023
      Citations
      0
    • HD 20329b: An ultra-short-period planet around a solar-type star found by TESS

      Context. Ultra-short-period (USP) planets are defined as planets with orbital periods shorter than one day. This type of planets is rare, highly irradiated, and interesting because their formation history is unknown. Aims: We aim to obtain precise mass and radius measurements to confirm the planetary nature of a USP candidate found by the

      Livingston, J. et al.

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      12
      2022
      Citations
      4
    • On the Characterization of GJ 504: A Magnetically Active Planet-host Star Observed by the Transiting Exoplanet Survey Satellite (TESS)

      We present the results of the analysis of the photometric data collected in long- and short-cadence mode by the Transiting Exoplanet Survey Satellite for GJ 504, a well-studied planet-hosting solar-like star, whose fundamental parameters have been largely debated during the last decade. Several attempts have been made by the present authors to

      Di Mauro, Maria Pia et al.

      Advertised on:

      11
      2022
      Citations
      1
    • Spinning up the Surface: Evidence for Planetary Engulfment or Unexpected Angular Momentum Transport?

      In this paper, we report the potential detection of a nonmonotonic radial rotation profile in a low-mass lower-luminosity giant star. For most low- and intermediate-mass stars, the rotation on the main sequence seems to be close to rigid. As these stars evolve into giants, the core contracts and the envelope expands, which should suggest a radial

      Tayar, Jamie et al.

      Advertised on:

      11
      2022
      Citations
      9
    • Hunting for anti-solar differentially rotating stars using the Rossby number. An application to the Kepler field

      Context. Anti-solar differential rotation profiles have been found for decades in numerical simulations of convective envelopes of solar-type stars. These profiles are characterized by a slow equator and fast poles (i.e., reversed with respect to the Sun) and have been found in simulations for high Rossby numbers. Rotation profiles like this have

      Noraz, Q. et al.

      Advertised on:

      11
      2022
      Citations
      7
    • TOI-2196 b: Rare planet in the hot Neptune desert transiting a G-type star

      The hot Neptune desert is a region hosting a small number of short-period Neptunes in the radius-instellation diagram. Highly irradiated planets are usually either small (R ≲ 2 R⊕) and rocky or they are gas giants with radii of ≳1 RJ. Here, we report on the intermediate-sized planet TOI-2196 b (TIC 372172128.01) on a 1.2 day orbit around a G-type

      Persson, Carina M. et al.

      Advertised on:

      10
      2022
      Citations
      9
    • Precise mass determination for the keystone sub-Neptune planet transiting the mid-type M dwarf G 9-40

      Context. Despite being a prominent subset of the exoplanet population discovered in the past three decades, the nature and provenance of sub-Neptune-sized planets is still one of the open questions in exoplanet science. Aims: For planets orbiting bright stars, precisely measuring the orbital and planet parameters of the system is the best approach

      Luque, R. et al.

      Advertised on:

      10
      2022
      Citations
      4
    • Confirmation and characterisation of three giant planets detected by TESS from the FIES/NOT and Tull/McDonald spectrographs

      We report the confirmation and characterisation of TOI-1820 b, TOI-2025 b, and TOI-2158 b, three Jupiter-sized planets on short-period orbits around G-type stars detected by TESS. Through our ground-based efforts using the FIES and Tull spectrographs, we have confirmed these planets and characterised their orbits, and find periods of around 4.9 d

      Knudstrup, Emil et al.

      Advertised on:

      11
      2022
      Citations
      7
    • 99 oscillating red-giant stars in binary systems with NASA TESS and NASA Kepler identified from the SB9-Catalogue

      Oscillating red-giant stars in binary systems are an ideal testbed for investigating the structure and evolution of stars in the advanced phases of evolution. With 83 known red giants in binary systems, of which only ∼40 have determined global seismic parameters and orbital parameters, the sample is small compared to the numerous known oscillating

      Advertised on:

      11
      2022
      Citations
      6
    • A 4 Gyr M-dwarf Gyrochrone from CFHT/MegaPrime Monitoring of the Open Cluster M67

      We present stellar rotation periods for late K- and early M-dwarf members of the 4 Gyr old open cluster M67 as calibrators for gyrochronology and tests of stellar spin-down models. Using Gaia EDR3 astrometry for cluster membership and Pan-STARRS (PS1) photometry for binary identification, we build this set of rotation periods from a campaign of

      Dungee, Ryan et al.

      Advertised on:

      10
      2022
      Citations
      20
    • SPECULOOS Northern Observatory: Searching for Red Worlds in the Northern Skies

      SPECULOOS is a ground-based transit survey consisting of six identical 1 m robotic telescopes. The immediate goal of the project is to detect temperate terrestrial planets transiting nearby ultracool dwarfs (late M-dwarf stars and brown dwarfs), which could be amenable for atmospheric research with the next generation of telescopes. Here, we report

      Burdanov, Artem Y. et al.

      Advertised on:

      10
      2022
      Citations
      8
    • Solar-like oscillations and ellipsoidal variations in TESS observations of the binary 12 Boötis

      Binary stars in which oscillations can be studied in either or both components can provide powerful constraints on our understanding of stellar physics. The bright binary 12 Boötis (12 Boo) is a particularly promising system because the primary is roughly 60 per cent brighter than the secondary despite being only a few per cent more massive. Both

      Ball, Warrick H. et al.

      Advertised on:

      11
      2022
      Citations
      1
    • Sub-stellar companions of intermediate-mass stars with CoRoT: CoRoT-34b, CoRoT-35b, and CoRoT-36b

      Theories of planet formation give contradicting results of how frequent close-in giant planets of intermediate mass stars (IMSs; $1.3\le M_{\star }\le 3.2\, \mathrm{M}_{\odot }$) are. Some theories predict a high rate of IMSs with close-in gas giants, while others predict a very low rate. Thus, determining the frequency of close-in giant planets of

      Sebastian, D. et al.

      Advertised on:

      10
      2022
      Citations
      8
    • The Origin of Weakened Magnetic Braking in Old Solar Analogs

      The rotation rates of main-sequence stars slow over time as they gradually lose angular momentum to their magnetized stellar winds. The rate of angular momentum loss depends on the strength and morphology of the magnetic field, the mass-loss rate, and the stellar rotation period, mass, and radius. Previous observations suggested a shift in magnetic

      Metcalfe, Travis S. et al.

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      7
      2022
      Citations
      18
    • Magnetic activities on two single-lined RS Canum Venaticorum binaries IM Pegasi and σ Geminorum

      We present the study on continuous high-resolution spectroscopic observations of two long-period single-lined RS Canum Venaticorum (RS CVn) binary stars IM Pegasi (IM Peg) and σ Geminorum (σ Gem), obtained with the Hertzsprung SONG telescope during the 2015-2016 season. Chromospheric activity indicators Hα, $\rm{Na\,\,{\small I}}$ D1, D2 doublet, $

      Cao, Dongtao et al.

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      8
      2022
      Citations
      2
    • A low-eccentricity migration pathway for a 13-h-period Earth analogue in a four-planet system

      It is commonly accepted that exoplanets with orbital periods shorter than one day, also known as ultra-short-period (USP) planets, formed further out within their natal protoplanetary disks before migrating to their current-day orbits via dynamical interactions. One of the most accepted theories suggests a violent scenario involving high

      Serrano, Luisa Maria et al.

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      4
      2022
      Citations
      9

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