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

    • Noise properties of the CoRoT data. A planet-finding perspective
      In this short paper, we study the photometric precision of stellar light curves obtained by the CoRoT satellite in its planet-finding channel, with a particular emphasis on the time scales characteristic of planetary transits. Together with other articles in the same issue of this journal, it forms an attempt to provide the building blocks for a
      Aigrain, S. et al.

      Advertised on:

      10
      2009
      Citations
      50
    • Ground-based photometry of space-based transit detections: photometric follow-up of the CoRoT  mission
      The motivation, techniques and performance of the ground-based photometric follow-up of transit detections by the CoRoT space mission are presented. Its principal raison d'être arises from the much higher spatial resolution of common ground-based telescopes in comparison to CoRoT's cameras. This allows the identification of many transit candidates
      Deeg, H. J. et al.

      Advertised on:

      10
      2009
      Citations
      80
    • Ground-based Near-infrared Observations of the Secondary Eclipse of CoRoT-2b
      We present the results of a ground-based search for the secondary eclipse of the 3.3 M Jup transiting planet CoRoT-2b. We performed near-infrared photometry using the LIRIS instrument on the 4.2 m William Herschel Telescope, in the H and Ks filters. We monitored the star around two expected secondary eclipses in two nights under very good observing
      Alonso, R. et al.

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      4
      2010
      Citations
      31
    • Extrasolar planet detection by binary stellar eclipse timing: evidence for a third body around CM Draconis
      Aims:Our objective is to elucidate the physical process that causes the observed observed-minus-calculated (O-C) behavior in the M4.5/M4.5 binary CM Dra and to test for any evidence of a third body around the CM Dra system. Methods: New eclipse minimum timings of CM Dra were obtained between the years 2000 and 2007. The O-C times of the system are
      Deeg, H. J. et al.

      Advertised on:

      3
      2008
      Citations
      47
    • Exoplanet discoveries with the CoRoT space observatory
      The CoRoT space observatory is a project which is led by the French space agency CNES and leading space research institutes in Austria, Brazil, Belgium, Germany and Spain and also the European Space Agency ESA. CoRoT observed since its launch in December 27, 2006 about 100 000 stars for the exoplanet channel, during 150 days uninterrupted high
      Lammer, H. et al.

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      12
      2010
      Citations
      4
    • Exo-Dat: An Information System in Support of the CoRoT/Exoplanet Science
      Exo-Dat is a database and an information system created primarily in support of the exoplanet program of the COnvection ROtation & planetary Transits (CoRoT) mission. In the directions of CoRoT pointings, it provides a united interface to several sets of data: stellar published catalogs, photometric and spectroscopic data obtained during the
      Deleuil, M. et al.

      Advertised on:

      8
      2009
      Citations
      100
    • CoRoT LRa02_E2_0121: Neptune-size planet candidate turns into a hierarchical triple system with a giant primary
      This paper presents the case of CoRoT LRa02_E2_0121, which was initially classified as a Neptune-size transiting-planet candidate on a relatively wide orbit of 36.3 days. Follow-up observations were performed with UVES, Sandiford, SOPHIE, and HARPS. These observations revealed a faint companion in the spectra. To find the true nature of the system
      Tal-Or, L. et al.

      Advertised on:

      10
      2011
      Citations
      8
    • A transiting giant planet with a temperature between 250K and 430K
      Of the over 400 known exoplanets, there are about 70 planets that transit their central star, a situation that permits the derivation of their basic parameters and facilitates investigations of their atmospheres. Some short-period planets, including the first terrestrial exoplanet (CoRoT-7b), have been discovered using a space mission designed to
      Deeg, H. J. et al.

      Advertised on:

      3
      2010
      Citations
      82
    • CoRoT Measures Solar-Like Oscillations and Granulation in Stars Hotter Than the Sun
      Oscillations of the Sun have been used to understand its interior structure. The extension of similar studies to more distant stars has raised many difficulties despite the strong efforts of the international community over the past decades. The CoRoT (Convection Rotation and Planetary Transits) satellite, launched in December 2006, has now
      Michel, Eric et al.

      Advertised on:

      10
      2008
      Citations
      235
    • Preliminary results on the contribution of the convection motions to the Doppler velocity signal
      This investigation aims to study the correlation of the solar background with atmosphere. We used high resolution observations of the NaDl spectral line. In fact the large span in formation heights of this spectral line allowed us to infer the signal from photosphere to chromosphere. We analyzed the data by applying the SIR code (Stokes Inversion
      Simoniello, R. et al.

      Advertised on:

      10
      2008
      Citations
      0
    • Infrared astronomical characteristics of the Roque de los Muchachos Observatory: precipitable water vapour statistics
      We present measurements of the atmospheric water vapour content above the Roque de los Muchachos Observatory (ORM) obtained using the Global Positioning System (GPS). The GPS measurements have been evaluated by comparison with 940-nm radiometer observations. A statistical analysis of the GPS measurements points to the ORM as an observing site with
      García-Lorenzo, B. et al.

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      7
      2010
      Citations
      22
    • Ground-based Multisite Observations of Two Transits of HD 80606b
      We present ground-based optical observations of the 2009 September and 2010 January transits of HD 80606b. Based on three partial light curves of the 2009 September event, we derive a midtransit time of Tc [HJD] = 2455099.196 ± 0.026, which is about 1σ away from the previously predicted time. We observed the 2010 January event from nine different
      Shporer, A. et al.

      Advertised on:

      10
      2010
      Citations
      13
    • Limits to the planet candidate GJ 436c
      We report on H-band, ground-based observations of a transit of the hot Neptune GJ 436b. Once combined to achieve sampling equivalent to archived observations taken with Spitzer, our measurements reach comparable precision levels. We analyze both sets of observations in a consistent way, and measure the rate of orbital inclination change to be of 0
      Alonso, R. et al.

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      8
      2008
      Citations
      68
    • TrES-5: A Massive Jupiter-sized Planet Transiting a Cool G Dwarf
      We report the discovery of TrES-5, a massive hot Jupiter that transits the star GSC 03949-00967 every 1.48 days. From spectroscopy of the star we estimate a stellar effective temperature of T eff = 5171 ± 36 K, and from high-precision B, R, and I photometry of the transit we constrain the ratio of the semimajor axis a and the stellar radius R
      Mandushev, Georgi et al.

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      11
      2011
      Citations
      19
    • Transit timing analysis of the exoplanets TrES-1 and TrES-2
      Aims. The aim of this work is a detailed analysis of transit light curves from TrES-1 and TrES-2, obtained over a period of three to four years, in order to search for variabilities in observed mid-transit times and to set constraints on the presence of additional third bodies. Methods: Using the IAC 80 cm telescope, we observed transits of TrES-1
      Rabus, M. et al.

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      12
      2009
      Citations
      39
    • SYMPA, a dedicated instrument for Jovian seismology. II. Real performance and first results
      Aims: SYMPA is the first instrument dedicated to the observation of free oscillations of Jupiter. Its principles and theoretical performance have been presented in Paper I. This second paper describes the data processing method, the real instrumental performance and presents the first results of a Jovian observation run, lead in 2005 at Teide
      Gaulme, P. et al.

      Advertised on:

      11
      2008
      Citations
      11
    • Detection of transit timing variations in excess of one hour in the Kepler multi-planet candidate system KOI 806 with the GTC
      Aims: We report the detection of transit timing variations (TTVs) well in excess of one hour in the Kepler multi-planet candidate system KOI 806. This system exhibits transits consistent with three separate planets - a Super-Earth, a Jupiter, and a Saturn - lying very nearly in a 1:2:5 resonance, respectively. Methods: We used the Kepler public
      Tingley, B. et al.

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      12
      2011
      Citations
      13
    • Constraints of a pulsation frequency on stellar parameters in the eclipsing spectroscopic binary system V577 Oph
      We present a preliminary spectroscopic analysis of the binary system V577Oph, observed during the summer of 2007 on the 2.6 m NOT telescope on La Palma. We have obtained time series spectroscopic observations, which show clear binary motion as well as radial velocity variations due to pulsation in the primary star. By modelling the radial
      Creevey, O. L. et al.

      Advertised on:

      12
      2010
      Citations
      3
    • Constraining the Properties of Delta Scuti Stars Using Spectroscopic Eclipsing Binary Systems
      Many stars exhibit stellar pulsations, favoring them for asteroseismic analyses. Interpreting the oscillations requires some knowledge of the oscillation mode geometry (spherical degree, radial, and azimuthal orders). The δ Scuti stars (1.5-2.5 M sun) often show just one or few pulsation frequencies. Although this may promise a successful
      Creevey, O. L. et al.

      Advertised on:

      5
      2011
      Citations
      7
    • An eclipsing post-common-envelope binary in the field of the Kepler mission
      We present a new eclipsing post-common-envelope binary, identified inside the Kepler field prior to the launch of the spacecraft. Multifilter photometry and radial velocity data are analysed with an eclipsing-binary modelling code to determine the physical parameters of the binary. Spectra of the system within the primary eclipse and uneclipsed
      Almenara, J. M. et al.

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      3
      2012
      Citations
      9

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