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

    • Solar-like Oscillations in KIC 11395018 and KIC 11234888 from 8 Months of Kepler Data

      We analyze the photometric short-cadence data obtained with the Kepler mission during the first 8 months of observations of two solar-type stars of spectral types G and F: KIC 11395018 and KIC 11234888, respectively, the latter having a lower signal-to-noise ratio (S/N) compared with the former. We estimate global parameters of the acoustic (p)

      Mathur, S. et al.

      Advertised on:

      6
      2011
      Citations
      69
    • Solar-like oscillations in HD 181420: data analysis of 156 days of CoRoT data

      Context: The estimate of solar-like oscillation properties, such as their frequencies, amplitudes and lifetimes, is challenging because of their low amplitudes and will benefit from long and uninterrupted observing runs. The space telescope CoRoT allows us to obtain high-performance photometric data over a long and quasi continuous period. Among

      Barban, C. et al.

      Advertised on:

      10
      2009
      Citations
      90
    • Seismic Evidence for a Rapidly Rotating Core in a Lower-giant-branch Star Observed with Kepler

      Rotation is expected to have an important influence on the structure and the evolution of stars. However, the mechanisms of angular momentum transport in stars remain theoretically uncertain and very complex to take into account in stellar models. To achieve a better understanding of these processes, we desperately need observational constraints on

      Deheuvels, S. et al.

      Advertised on:

      9
      2012
      Citations
      321
    • Radius Determination of Solar-type Stars Using Asteroseismology: What to Expect from the Kepler Mission

      For distant stars, as observed by the NASA Kepler satellite, parallax information is currently of fairly low quality and is not complete. This limits the precision with which the absolute sizes of the stars and their potential transiting planets can be determined by traditional methods. Asteroseismology will be used to aid the radius determination

      Stello, Dennis et al.

      Advertised on:

      8
      2009
      Citations
      160
    • Predicting the Detectability of Oscillations in Solar-type Stars Observed by Kepler

      Asteroseismology of solar-type stars has an important part to play in the exoplanet program of the NASA Kepler Mission. Precise and accurate inferences on the stellar properties that are made possible by the seismic data allow very tight constraints to be placed on the exoplanetary systems. Here, we outline how to make an estimate of the

      Chaplin, W. J. et al.

      Advertised on:

      5
      2011
      Citations
      127
    • Oscillation mode frequencies of 61 main-sequence and subgiant stars observed by Kepler

      Context. Solar-like oscillations have been observed by Kepler and CoRoT in several solar-type stars, thereby providing a way to probe the stars using asteroseismology Aims: We provide the mode frequencies of the oscillations of various stars required to perform a comparison with those obtained from stellar modelling. Methods: We used a time series

      Appourchaux, T. et al.

      Advertised on:

      7
      2012
      Citations
      132
    • Kepler-21b: A 1.6 R Earth Planet Transiting the Bright Oscillating F Subgiant Star HD 179070

      We present Kepler observations of the bright (V = 8.3), oscillating star HD 179070. The observations show transit-like events which reveal that the star is orbited every 2.8 days by a small, 1.6 R Earth object. Seismic studies of HD 179070 using short cadence Kepler observations show that HD 179070 has a frequency-power spectrum consistent with

      Howell, Steve B. et al.

      Advertised on:

      2
      2012
      Citations
      112
    • Granulation in Red Giants: Observations by the Kepler Mission and Three-dimensional Convection Simulations

      The granulation pattern that we observe on the surface of the Sun is due to hot plasma rising to the photosphere where it cools down and descends back into the interior at the edges of granules. This is the visible manifestation of convection taking place in the outer part of the solar convection zone. Because red giants have deeper convection

      Mathur, S. et al.

      Advertised on:

      11
      2011
      Citations
      145
    • Global asteroseismic properties of solar-like oscillations observed by Kepler: a comparison of complementary analysis methods

      We present the asteroseismic analysis of 1948 F-, G- and K-type main-sequence and subgiant stars observed by the National Aeronautics and Space Administration Kepler mission. We detect and characterize solar-like oscillations in 642 of these stars. This represents the largest cohort of main-sequence and subgiant solar-like oscillators observed to

      Verner, G. A. et al.

      Advertised on:

      8
      2011
      Citations
      106
    • Fundamental properties of five Kepler stars using global asteroseismic quantities and ground-based observations

      We present an asteroseismic study of the solar-like stars KIC 11395018, KIC 10273246, KIC 10920273, KIC 10339342, and KIC 11234888 using short-cadence time series of more than eight months from the Kepler satellite. For four of these stars, we derive atmospheric parameters from spectra acquired with the Nordic Optical Telescope. The global seismic

      Creevey, O. L. et al.

      Advertised on:

      1
      2012
      Citations
      38
    • First asteroseismic results from CoRoT

      About one year after the end of the first observational run and six months after the first CoRoT data delivery, we comment the data exploitation progress for different types of stars. We consider first results to illustrate how these data of unprecedented quality shed a new light on the field of stellar seismology.

      Michel, E. et al.

      Advertised on:

      12
      2008
      Citations
      30
    • Evidence for the Impact of Stellar Activity on the Detectability of Solar-like Oscillations Observed by Kepler

      We use photometric observations of solar-type stars, made by the NASA Kepler Mission, to conduct a statistical study of the impact of stellar surface activity on the detectability of solar-like oscillations. We find that the number of stars with detected oscillations falls significantly with increasing levels of activity. The results present strong

      Chaplin, W. J. et al.

      Advertised on:

      5
      2011
      Citations
      123
    • Ensemble Asteroseismology of Solar-Type Stars with the NASA Kepler Mission

      In addition to its search for extrasolar planets, the NASA Kepler mission provides exquisite data on stellar oscillations. We report the detections of oscillations in 500 solar-type stars in the Kepler field of view, an ensemble that is large enough to allow statistical studies of intrinsic stellar properties (such as mass, radius, and age) and to

      Chaplin, W. J. et al.

      Advertised on:

      4
      2011
      Citations
      297
    • Effect of line-of-sight inclinations on the observation of solar activity cycle: Lessons for CoRoT & Kepler

      CoRoT and Kepler missions are collecting data of solar-like oscillating stars of unprecedented quality. Moreover, thanks to the length of the time series, we are able to study their seismic variability. In this work we use numerical simulations based on the last 3 solar cycles to analyze the light curves as a function of the line-of-sight

      Vázquez Ramió, H. et al.

      Advertised on:

      1
      2011
      Citations
      5
    • Determining global parameters of the oscillations of solar-like stars

      Context. Helioseismology has enabled us to better understand the solar interior, while also allowing us to better constrain solar models. But now is a tremendous epoch for asteroseismology as space missions dedicated to studying stellar oscillations have been launched within the last years (MOST and CoRoT). CoRoT has already proved valuable results

      Mathur, S. et al.

      Advertised on:

      2
      2010
      Citations
      218
    • Detection of Solar-like Oscillations from Kepler Photometry of the Open Cluster NGC 6819

      Asteroseismology of stars in clusters has been a long-sought goal because the assumption of a common age, distance, and initial chemical composition allows strong tests of the theory of stellar evolution. We report results from the first 34 days of science data from the Kepler Mission for the open cluster NGC 6819—one of the four clusters in the

      Stello, Dennis et al.

      Advertised on:

      4
      2010
      Citations
      82
    • CoRoT sounds the stars: p-mode parameters of Sun-like oscillations on HD 49933

      Context: The first asteroseismology results from CoRoT are presented, on a star showing Sun-like oscillations. We have analyzed a 60 day lightcurve of high-quality photometric data collected by CoRoT on the F5 V star HD 49933. The data reveal a rich spectrum of overtones of low-degree p modes. Aims: Our aim was to extract robust estimates of the

      Appourchaux, T. et al.

      Advertised on:

      9
      2008
      Citations
      230
    • CoRoT Reveals a Magnetic Activity Cycle in a Sun-Like Star

      The 11-year activity cycle of the Sun is a consequence of a dynamo process occurring beneath its surface. We analyzed photometric data obtained by the CoRoT space mission, showing solarlike oscillations in the star HD49933, for signatures of stellar magnetic activity. Asteroseismic measurements of global changes in the oscillation frequencies and

      García, Rafael A. et al.

      Advertised on:

      8
      2010
      Citations
      236
    • Calibrating Convective Properties of Solar-like Stars in the Kepler Field of View

      Stellar models generally use simple parameterizations to treat convection. The most widely used parameterization is the so-called mixing-length theory where the convective eddy sizes are described using a single number, α, the mixing-length parameter. This is a free parameter, and the general practice is to calibrate α using the known properties of

      Bonaca, Ana et al.

      Advertised on:

      8
      2012
      Citations
      82
    • Asteroseismology of the Solar Analogs 16 Cyg A and B from Kepler Observations

      The evolved solar-type stars 16 Cyg A and B have long been studied as solar analogs, yielding a glimpse into the future of our own Sun. The orbital period of the binary system is too long to provide meaningful dynamical constraints on the stellar properties, but asteroseismology can help because the stars are among the brightest in the Kepler field

      Metcalfe, T. S. et al.

      Advertised on:

      3
      2012
      Citations
      151

    Related talks

    No related talks were found.

    Related conferences

    No related conferences were found.