Start year
2000
Organizational Unit
Organizing institutions
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.
Members
Principal investigator
Savita
Mathur
Project staff
Juan Antonio
Belmonte Avilés
Hans Jörg
Deeg Deeg
Roi
Alonso Sobrino
Pere Lluís
Pallé Manzano
Fernando
Pérez Hernández
Teodoro
Roca Cortés
Savita
Mathur
Antonio
Jiménez Mancebo
Collaborators
Dr.
A. Eff-Darwich
Dr.
R. García
Dr.
Mads F. Anderson
Dr.
J. Christensen Dalsgaard
Dr.
F. Grundahl
Dr.
H. Kjeldsen
Dr.
Enrico Corsaro
Dr.
M. Cunha
Dr.
G. Davies
Dr.
T. Metcalfe
Dr.
T. Bedding
Dr.
D. Chou
Dr.
J. Fernández
Dr.
F. Hill
Dr.
S. Korzennik
Dr.
M. Deleuil
Dr.
D. Gandolfi
Dr.
M. Fridlund
Dr.
L. Doyle
Dr.
H. Rauer
Dr.
V. Kozhevnikov
Dr.
A. Hatzes
Dr.
T. Mazeh
Dr.
D. Queloz
Dr.
J. Ballot
Dr.
O. Creevey
Dr.
T. Boyajian
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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Characterization of Exoplanets: Secondary EclipsesWhen an exoplanet passes behind its host star, we can measure the time of the occultation, its depth, and its color. In this chapter we describe how these observables can be used to deduce physical characteristics of the planet such as its averaged dayside emission, departures from uniform disk illumination, or a precise measurement of the orbitalAlonso, Roi
Advertised on:
2018 -
The Way to Circumbinary PlanetsThe historic quest to detect circumbinary planets (CBPs) dates back to a time before the first extrasolar planets were detected. Eclipsing binary star systems (EBs) were considered prime targets for the detection of CBP transits, as it was considered likely that the planetary orbits would also be close to edge on to our line of sight and so crossDoyle, Laurance R. et al.
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2018 -
Transit Photometry as an Exoplanet Discovery MethodPhotometry with the transit method has arguably been the most successful exoplanet discovery method to date. A short overview about the rise of that method to its present status is given. The method's strength is the rich set of parameters that can be obtained from transiting planets, in particular in combination with radial velocity observationsDeeg, Hans J. et al.
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2018 -
Impact of Exoplanet Science in the Early Twenty-First CenturyThe impact of exoplanet science at the beginning of the twenty-first century is studied from two different approaches: the impact in astronomical science both by professionals and citizen scientists and through public outreach. The impact of exoplanetology on the scientific community as well as on the informed public is presented by severalDeeg, Hans J. et al.
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2018 -
Planets, candidates, and binaries from the CoRoT/Exoplanet programme. The CoRoT transit catalogueThe CoRoT space mission observed 163 665 stars over 26 stellar fields in the faint star channel. The exoplanet teams detected a total of 4123 transit-like features in the 177 454 light curves. We present the complete re-analysis of all these detections carried out with the same softwares so that to ensure their homogeneous analysis. Although theDeleuil, M. et al.
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112018 -
Brown dwarf companion with a period of 4.6 yr interacting with the hot Jupiter CoRoT-20 bWe report the discovery of an additional substellar companion in the CoRoT-20 system based on six years of HARPS and SOPHIE radial velocity follow-up. CoRoT-20 c has a minimum mass of 17 ± 1 MJup and orbits the host star in 4.59 ± 0.05 yr, with an orbital eccentricity of 0.60 ± 0.03. This is the first identified system with an eccentric hot JupiterRey, J. et al.
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112018 -
TESS's first planet. A super-Earth transiting the naked-eye star π MensaeWe report on the confirmation and mass determination of π Men c, the first transiting planet discovered by NASA's TESS space mission. π Men is a naked-eye (V = 5.65 mag), quiet G0 V star that was previously known to host a sub-stellar companion (π Men b) on a longperiod (Porb = 2091 days), eccentric (e = 0.64) orbit. Using TESS time-seriesGandolfi, D. et al.
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112018 -
FliPer: A global measure of power density to estimate surface gravities of main-sequence solar-like stars and red giantsAsteroseismology provides global stellar parameters such as masses, radii, or surface gravities using mean global seismic parameters and effective temperature for thousands of low-mass stars (0.8 M⊙ M 3 M⊙). This methodology has been successfully applied to stars in which acoustic modes excited by turbulent convection are measured. Other methodsBugnet, L. et al.
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112018 -
The Gaia-ESO Survey: properties of newly discovered Li-rich giantsAims: We report 20 new lithium-rich giants discovered within the Gaia-ESO Survey, including the first Li-rich giant with an evolutionary stage confirmed by CoRoT (Convection, Rotation and planetary Transits) data. We present a detailed overview of the properties of these 20 stars. Methods: Atmospheric parameters and abundances were derived in modelSmiljanic, R. et al.
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92018 -
Non-linear seismic scaling relationsContext. In recent years the global seismic scaling relations for the frequency of maximum power, νmax ∝ g / √Teff, and for the large frequency separation, Δν ∝ √ρ¯, have drawn attention in various fields of astrophysics. This is because these relations can be used to estimate parameters, such as the mass and radius of stars that show solar-likeKallinger, T. et al.
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82018 -
The Kepler Follow-up Observation Program. II. Stellar Parameters from Medium- and High-resolution SpectroscopyWe present results from spectroscopic follow-up observations of stars identified in the Kepler field and carried out by teams of the Kepler Follow-up Observation Program. Two samples of stars were observed over 6 yr (2009–2015): 614 standard stars (divided into “platinum” and “gold” categories) selected based on their asteroseismic detections andFurlan, E. et al.
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72018 -
Testing tidal theory for evolved stars by using red giant binaries observed by KeplerTidal interaction governs the redistribution of angular momentum in close binary stars and planetary systems and determines the systems evolution towards the possible equilibrium state. Turbulent friction acting on the equilibrium tide in the convective envelope of low-mass stars is known to have a strong impact on this exchange of angular momentumBeck, P. G. et al.
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92018 -
Oscillating red giants in eclipsing binary systems: empirical reference value for asteroseismic scaling relationThe internal structures and properties of oscillating red-giant stars can be accurately inferred through their global oscillation modes (asteroseismology). Based on 1460 d of Kepler observations we perform a thorough asteroseismic study to probe the stellar parameters and evolutionary stages of three red giants in eclipsing binary systems. WeThemeßl, N. et al.
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82018 -
HD 89345: a bright oscillating star hosting a transiting warm Saturn-sized planet observed by K2We report the discovery and characterization of HD 89345b (K2-234b; EPIC 248777106b), a Saturn-sized planet orbiting a slightly evolved star. HD 89345 is a bright star (V = 9.3 mag) observed by the K2 mission with 1 min time sampling. It exhibits solar-like oscillations. We conducted asteroseismology to determine the parameters of the star, findingVan Eylen, V. et al.
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82018 -
The envelope of the power spectra of over a thousand δ Scuti stars. The T̅eff - νmax scaling relationCoRoT and Kepler high-precision photometric data allowed the detection and characterization of the oscillation parameters in stars other than the Sun. Moreover, thanks to the scaling relations, it is possible to estimate masses and radii for thousands of solar-type oscillating stars. Recently, a Δν - ρ relation has been found for δ Scuti stars. NowBarceló Forteza, S. et al.
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62018 -
The mass and age of the first SONG target: the red giant 46 LMiContext. The Stellar Observation Network Group (SONG) is an initiative to build a worldwide network of 1m telescopes with high-precision radial-velocity spectrographs. Here we analyse the first radial-velocity time series of a red-giant star measured by the SONG telescope at Tenerife. The asteroseismic results demonstrate a major increase in theFrandsen, S. et al.
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52018 -
Seismic probing of the first dredge-up event through the eccentric red-giant and red-giant spectroscopic binary KIC 9163796. How different are red-giant stars with a mass ratio of 1.015?Context. Binaries in double-lined spectroscopic systems (SB2) provide a homogeneous set of stars. Differences of parameters, such as age or initial conditions, which otherwise would have strong impact on the stellar evolution, can be neglected. The observed differences are determined by the difference in stellar mass between the two components. TheBeck, P. G. et al.
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42018 -
Low-frequency photospheric and wind variability in the early-B supergiant HD 2905Context. Despite important advances in space asteroseismology during the last decade, the early phases of evolution of stars with masses above 15 M⊙ (including the O stars and their evolved descendants, the B supergiants) have been only vaguely explored up to now. This is due to the lack of adequate observations for a proper characterization of theSimón-Díaz, S. et al.
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42018 -
Frequency dependence of p-mode frequency shifts induced by magnetic activity in Kepler solar-like starsThe variations of the frequencies of the low-degree acoustic oscillations in the Sun induced by magnetic activity show a dependence on radial order. The frequency shifts are observed to increase towards higher-order modes to reach a maximum of about 0.8 μHz over the 11-yr solar cycle. A comparable frequency dependence is also measured in two otherGarcía, R. A. et al.
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42018 -
K2 photometry and HERMES spectroscopy of the blue supergiant ρ Leo: rotational wind modulation and low-frequency wavesWe present an 80-d long uninterrupted high-cadence K2 light curve of the B1Iab supergiant ρ Leo (HD 91316), deduced with the method of halo photometry. This light curve reveals a dominant frequency of frot = 0.0373 d-1 and its harmonics. This dominant frequency corresponds with a rotation period of 26.8 d and is subject to amplitude and phaseAerts, C. et al.
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52018
