General
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.
Members
Results
Milestones
- 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.
- 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.
- 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).
- 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
- 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.
Scientific activity
Related publications
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Asteroseismology of KIC 11754974: a high-amplitude SX Phe pulsator in a 343-d binary system
The candidate SX Phe star KIC 11754974 shows a remarkably high number of combination frequencies in the Fourier amplitude spectrum: 123 of the 166 frequencies in our multifrequency fit are linear combinations of independent modes. Predictable patterns in frequency spacings are seen in the Fourier transform of the light curve. We present an analysis
Murphy, S. J. et al.Advertised on:
72013 -
Two new SB2 binaries with main sequence B-type pulsators in the Kepler field
Context. OB stars are important in the chemistry and evolution of the Universe, but the sample of targets that is well understood from an asteroseismological point of view is still too limited to provide feedback on the current evolutionary models. Aims: We extend this sample with two spectroscopic binary systems. Our goal is to provide orbital
Pápics, P. I. et al.Advertised on:
52013 -
Spectrum analysis of bright Kepler late B- to early F-stars
The Kepler satellite mission was designed to search for transiting exoplanets and delivers single band-pass light curves of a huge number of stars observed in the Cygnus-Lyra region. At the same time, it opens a new window for asteroseismology. In order to accomplish one of the required preconditions for the asteroseismic modelling of the stars
Uytterhoeven, K. et al.Advertised on:
62013 -
CoRoT 101186644: A transiting low-mass dense M-dwarf on an eccentric 20.7-day period orbit around a late F-star. Discovered in the CoRoT lightcurves
We present the study of the CoRoT transiting planet candidate 101186644, also named LRc01_E1_4780. Analysis of the CoRoT lightcurve and the HARPS spectroscopic follow-up observations of this faint (mV = 16) candidate revealed an eclipsing binary composed of a late F-type primary (Teff = 6090 ± 200 K) and a low-mass, dense late M-dwarf secondary on
Tal-Or, L. et al.Advertised on:
52013 -
Mode Parameters of δ Scuti Stars V830 Her and HD 163032 with Four-Year Data from the Taiwan Automated Telescope Network
We study two δ Scuti stars, V830 Her and HD 163032, using four-year asteroseismic photometric data taken with the Taiwan Automated Telescope Network. We check the consistency of the pulsational frequencies obtained from data of different years and sites with three different methods to remove the artificial frequencies. Fourteen frequencies are
Strelnikov, Dmitry et al.Advertised on:
12013 -
Constraining magnetic-activity modulations in three solar-like stars observed by CoRoT and NARVAL
Context. Stellar activity cycles are the manifestation of dynamo process running in the stellar interiors. They have been observed from years to decades thanks to the measurement of stellar magnetic proxies on the surface of the stars, such as the chromospheric and X-ray emissions, and to the measurement of the magnetic field with
Mathur, S. et al.Advertised on:
22013 -
Secondary eclipses in the CoRoT light curves. A homogeneous search based on Bayesian model selection
Aims: We aim to identify and characterize secondary eclipses in the original light curves of all published CoRoT planets using uniform detection and evaluation critetia. Methods: Our analysis is based on a Bayesian model selection between two competing models: one with and one without an eclipse signal. The search is carried out by mapping the
Parviainen, H. et al.Advertised on:
22013 -
Using a Mesoscale Meteorological Model to Reduce the Effect of Tropospheric Water Vapour from DInSAR Data: A Case Study for the Island of Tenerife, Canary Islands
Measurements of ground displacement through classical Differential Interferometric SAR (DInSAR) and advanced DInSAR techniques have been carried out over the entire actively volcanic island of Tenerife, Canary Islands. However, a detailed analysis of the effect of tropospheric water vapour on DInSAR at Tenerife should be carried out to evaluate its
González, Pablo J. et al.Advertised on:
82012 -
Ground-based multi-color photometry of the γ Doradus-δ Scuti hybrid star KIC 6761539
We present a preliminary analysis of the first three nights of multi-color photometric data for a γ Doradus-δ Scuti hybrid star (KIC 6761539) that is also being observed with the Kepler space telescope. We find that up to four (depending on the filter) of the highest amplitude modes, whose frequencies could be determined from Kepler data, are
Roth, M. et al.Advertised on:
122012 -
SONG-OT: The prototype SONG node at Tenerife
The prototype SONG node, SONG-OT, is currently being installed and tested at Observatory del Teide on Tenerife. SONG will be a global network of 1-m robotic telescopes, equipped with a high-resolution échelle spectrograph and dual-colour lucky imaging cameras. The network will be devoted to the seismic study of bright stars and characterisation of
SONG Team et al.Advertised on:
122012 -
Presentation of the reduction pipeline of the SONG échelle spectrograph
We give an overview of the spectral reduction pipeline that will be used to process the data of the échelle spectrograph of the SONG-OT telescope node of the SONG (Stellar Observations Network Group) network on Tenerife. In particular, we focus on the iodine absorption cell technique to derive precise radial velocity measurements. The telescope and
the SONG team et al.Advertised on:
122012 -
Study of HD 169392A observed by CoRoT and HARPS
Context. The results obtained by asteroseismology with data from space missions such as CoRoT and Kepler are providing new insights into stellar evolution. After five years of observations, CoRoT is continuing to provide high-quality data and we here present an analysis of the CoRoT observations of the double star HD 169392, complemented by ground
Roca-Cortés, T. et al.Advertised on:
12013 -
Characterizing Two Solar-type Kepler Subgiants with Asteroseismology: KIC 10920273 and KIC 11395018
Determining fundamental properties of stars through stellar modeling has improved substantially due to recent advances in asteroseismology. Thanks to the unprecedented data quality obtained by space missions, particularly CoRoT and Kepler, invaluable information is extracted from the high-precision stellar oscillation frequencies, which provide
Van Cleve, J. et al.Advertised on:
12013 -
From CoRoT 102899501 to the Sun. A time evolution model of chromospheric activity on the main sequence
Aims: The present study reports measurements of the rotation period of a young solar analogue, estimates of its surface coverage by photospheric starspots and of its chromospheric activity level, and derivations of its evolutionary status. Detailed observations of many young solar-type stars, such as the one reported in the present paper, provide
Gondoin, P. et al.Advertised on:
122012 -
Pulsational amplitude growth of the star KIC 3429637 (HD 178875) in the context of Am and ρ Pup stars
KIC 3429637 (HD 178875) is a δ Sct star whose light curve shows continuous pulsational amplitude growth in Kepler mission photometry. Analysis of the three largest amplitude peaks in the Fourier transform indicates different growth rates for all three. We have ruled out instrumental causes, and determine the amplitude growth to be intrinsic to the
Uytterhoeven, K. et al.Advertised on:
122012 -
Misleading variations in estimated rotational frequency splittings of solar p modes: consequences for helioseismology and asteroseismology
The aim of this paper is to investigate whether there are any 11-yr or quasi-biennial solar-cycle-related variations in solar rotational splitting frequencies of low-degree solar p modes. Although no 11-yr signals were observed, variations on a shorter time-scale (˜2 yr) were apparent. We show that the variations arose from complications/artefacts
Mathur, Savita et al.Advertised on:
62012 -
Intermediate Resolution Near-infrared Spectroscopy of 36 Late M Dwarfs
We present observations of 36 late M dwarfs obtained with the Keck II/NIRSPEC in the J band at a resolution of ~20,000. We have measured projected rotational velocities, absolute radial velocities, and pseudo-equivalent widths of atomic lines. Twelve of our targets did not have previous measurements in the literature. For the other 24 targets, we
Deshpande, R. et al.Advertised on:
102012 -
Fundamental Properties of Stars Using Asteroseismology from Kepler and CoRoT and Interferometry from the CHARA Array
We present results of a long-baseline interferometry campaign using the PAVO beam combiner at the CHARA Array to measure the angular sizes of five main-sequence stars, one subgiant and four red giant stars for which solar-like oscillations have been detected by either Kepler or CoRoT. By combining interferometric angular diameters, Hipparcos
Huber, D. et al.Advertised on:
112012 -
Multisite spectroscopic seismic study of the β Cep star V2052 Ophiuchi: inhibition of mixing by its magnetic field
We used extensive ground-based multisite and archival spectroscopy to derive observational constraints for a seismic modelling of the magnetic β Cep star V2052 Ophiuchi. The line-profile variability is dominated by a radial mode (f1 = 7.148 46 d-1) and by rotational modulation (Prot = 3.638 833 d). Two non-radial low-amplitude modes (f2 = 7.756 03
Briquet, M. et al.Advertised on:
112012 -
Variations of the solar granulation motions with height using the GOLF/SoHO experiment
Context: Below 1 mHz, the power spectrum of helioseismic velocity measurements is dominated by the spectrum of convective motions (granulation and supergranulation) and it is difficult to detect the low-order acoustic modes and gravity modes. Aims: We attempt to understand more clearly the behavior of solar granulation as a function of observing
Lefebvre, S. et al.Advertised on:
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