General
Los objetivos genéricos de este Proyecto son: 1) el estudio de la estructura y dinámica del interior solar, 2) la extensión de dicho estudio al caso de otras estrellas, 3) la búsqueda y caracterización de planetas extrasolares por métodos fotométricos (principalmente mediante el método de tránsitos) y espectroscópico (variaciones en la velocidad radial de la estrella) y 4) el análisis de las atmósferas de estos planetas.
Para el primer objetivo se utiliza la heliosismología tanto global (la que se obtiene de los modos propios de oscilación) como la local (que deriva del estudio de ondas viajeras). La sismología solar permite inferir de modo preciso información acerca de la estructura y dinámicas internas del Sol. El presente proyecto cubre las distintas facetas necesarias para alcanzar dicho objetivo, desde la instrumental, pasando por la observacional, técnicas de reducción, análisis e interpretación de los datos, así como el desarrollo de técnicas teóricas de inversión y elaboración de modelos de estructura y evolución.
Por otro lado, la astrosismología pretende obtener un conocimiento similar en otras estrellas. Hoy en día esta rama de la astrofísica está produciendo un gran número de resultados gracias a la enorme cantidad de estrellas observadas por las misiones espaciales CoRoT, Kepler y TESS, siendo posible extraer información sobre la estructura y dinámica de cientos de estrellas, tanto de tipo solar como de gigantes rojas. Todo ello se verá complementado con el desarrollo de la red SONG (Stellar Observations Network Group), una batería de telescopio en Tierra dotados con espectrógrafos.
La estrategia de utilización de tránsitos planetarios para descubrir la existencia de planetas alrededor de otras estrellas, consiste en la detección fotométrica de disminuciones de brillo de una estrella cuando uno de sus planetas está pasando entre ella y el observador. Actualmente esta metodología es la preferida para la investigación de planetas pequeños, no sólo por su sensibilidad sino también porque permite llevar a cabo estudios relativamente detallados de los planetas descubiertos. Esta tecnología es similar a la que se utiliza en helio y astrosismología por lo que se puede entender como una extensión lógica de lo aprendido con los anteriores objetivos. Por otro lado, es importante desarrollar algoritmos y métodos observacionales para la detección inequívoca y el análisis de los planetas, distinguiéndolos de los que resultan ser falsas alarmas.
El panorama actual para los estudios de exoplanetas involucra nuevas misiones espaciales como CHEOPS y TESS que serán seguidos por JWST y en 2026, PLATO. Por lo tanto, se abre una ventana temporal en la que los observatorios terrestres pueden complementar estos datos. Para ello seguimos llevando a cabo observaciones usando principalmente TNG, NOT, GTC.
Members
Results
- Miembros del grupo (P. G. Beck, H. Deeg, S. Mathur, F. Pérez, C. Régulo) estuvieron involucrados en el descubrimiento y caracterización de un "Saturno caliente" que hospeda la estrella HD 89345 observada con la misión K2 y confirmada con medidas de VR. El análisis sísmico permitió obtener estimaciones precisas de los parámetros estelares.
- P.G.Beck dirigió dos artículos sobre binarias con gigantes rojas, usando técnicas astrosimológicas para mejorar la comprensión de su estructura y efectos de marea. También se estudio la mezcla de material en su interior midiendo abundancias de Litio.
- S. Mathur participó en el análisis del primer planeta descubierto por la misión TESS, que orbita la estrella Pi Men. El análisis sísmico condujo a una detección marginal pero dió una pista del potencial uso de la astrosismología con TESS (Gandolfi et al. 2018).
- Proyecto "Solar-SONG". Por vez primera se ha utilizado instrumentación estelar (espectrógrafo SONG) para obtener medidas precisas de la velocidad radial del Sol con alta cadencia temporal (4 s.) y duración suficiente (57 días consecutivos) como para permitir el estudio detallado del espectro de oscilaciones (modos-p) y obtener sus parámetros globales
- Los investigadores Hans J. Deeg y Juan Antonio Belmonte coordinaron la edición del libro "Handbook of Exoplanets" con 160 artículos y la participación de más de 300 especialistas. Tres años de trabajo resultaron en una colección completa y actualizada del estudio de los planetas más allá del sistema solar.
Scientific activity
Publicaciones relacionadas
-
Reliability of P mode event classification using contemporaneous BiSON and GOLF observationsWe carried out a comparison of the signals seen in contemporaneous BiSON and GOLF data sets. Both instruments perform Doppler shift velocity measurements in integrated sunlight, although BiSON perform measurements from the two wings of potassium absorption line and GOLF from one wing of the NaD1 line. Discrepancies between the two datasets haveSimoniello, R. et al.
Advertised on:
102008 -
Misaligned spin-orbit in the XO-3 planetary system?The transiting extrasolar planet XO-3b is remarkable, with a high mass and eccentric orbit. These unusual characteristics make it interesting to test whether its orbital plane is parallel to the equator of its host star, as it is observed for other transiting planets. We performed radial velocity measurements of XO-3 with the SOPHIE spectrograph atHébrard, G. et al.
Advertised on:
92008 -
Helioseismology program for the PICARD satelliteThe PICARD mission is a CNES micro-satellite to be launched in 2009. Its goal is to better understand the Sun and the potential impact of its activity on earth climate by measuring simultaneously the solar total and spectral irradiance, diameter, shape and oscillations. We present the scientific objectives, instrumental requirements and dataCorbard, T. et al.
Advertised on:
62008 -
T-Lyr1-17236: A Long-Period Low-Mass Eclipsing BinaryWe describe the discovery of a 0.68+0.52 Msolar eclipsing binary (EB) with an 8.4 day orbital period, found through a systematic search of 10 fields of the Trans-atlantic Exoplanet Survey (TrES). Such long-period low-mass EBs constitute critical test cases for resolving the long-standing discrepancy between the theoretical and observational massDevor, Jonathan et al.
Advertised on:
112008 -
Measurement of Low Signal-To-Noise Ratio Solar p-Modes in Spatially Resolved Helioseismic DataWe present an adaptation of the rotation-corrected, m-averaged spectrum technique designed to observe low signal-to-noise ratio (S/N), low-frequency solar p-modes. The frequency shift of each of the 2l + 1 m spectra of a given (n, l) multiplet is chosen that maximizes the likelihood of the m-averaged spectrum. A high S/N can result from combiningSalabert, D. et al.
Advertised on:
52009 -
A Stellar Model-fitting Pipeline for Asteroseismic Data from the Kepler MissionOver the past two decades, helioseismology has revolutionized our understanding of the interior structure and dynamics of the Sun. Asteroseismology will soon place this knowledge into a broader context by providing structural data for hundreds of Sun-like stars. Solar-like oscillations have already been detected from the ground in several starsMetcalfe, T. S. et al.
Advertised on:
72009 -
A semi-automatic procedure for abundance determination of A- and F-type starsA variety of physical processes leading to different types of pulsations and chemical compositions are observed between A- and F-type stars. To investigate the underlying mechanisms responsible for these processes in stars with similar locations in the Hertzsprung-Russell diagram, an accurate abundance determination is needed, among others. HereHekker, S. et al.
Advertised on:
72009 -
Turbulent eddy-time-correlation in the solar convective zoneTheoretical modeling of the driving processes of solar-like oscillations is a powerful way of understanding the properties of the convective zones of solar-type stars. In this framework, the description of the temporal correlation between turbulent eddies is an essential ingredient to model mode amplitudes. However, there is a debate between aBelkacem, K. et al.
Advertised on:
112010 -
A Seismic Signature of a Second Dynamo?The Sun is a variable star whose magnetic activity varies most perceptibly on a timescale of approximately 11 years. However, significant variation is also observed on much shorter timescales. We observe a quasi-biennial (2 year) signal in the natural oscillation frequencies of the Sun. The oscillation frequencies are sensitive probes of the solarFletcher, Stephen T. et al.
Advertised on:
72010 -
Seismic signatures of stellar cores of solar-like pulsators: Dependence on mass and ageUseful information from the inner layers of stellar pulsators may be derived from the study of their oscillations. In this paper we analyse three diagnostic tools suggested in the literature built from the oscillation frequencies computed for a set of main sequence models with masses between 1.0 M&sun; and 1.6 M&sun;, to check what information theyBrandão, I. M. et al.
Advertised on:
122010 -
Mode visibilities in radial velocity and photometric Sun-as-a-star helioseismic observationsWe analyze more than 5000 days of high-quality Sun-as-a-star, radial velocity GOLF and photometric VIRGO/SPM helioseismic observations to extract precise estimates of the visibilities of the low-degree p modes and the m-height ratios of the l = 2 and 3 multiplets in the solar acoustic spectrum. The mode visibilities are shown to be larger duringSalabert, D. et al.
Advertised on:
42011 -
Search for radial velocity variations in eight M-dwarfs with NIRSPEC/Keck IIContext. Radial velocity (RV) measurements from near-infrared spectra have become a potentially powerful tool to search for planets around cool stars and sub-stellar objects. As part of a large survey to characterize M-dwarfs using NIRSPEC at Keck II, we obtained spectra of eight late M-dwarfs (spectral types M5.0-M8.0) during two or more observingRodler, F. et al.
Advertised on:
22012 -
The quest for the solar g modesSolar gravity modes (or g modes)—oscillations of the solar interior on which buoyancy acts as the restoring force—have the potential to provide unprecedented inference on the structure and dynamics of the solar core, inference that is not possible with the well-observed acoustic modes (or p modes). The relative high amplitude of the g-modeAppourchaux, T. et al.
Advertised on:
22010 -
The quasi-biennial periodicity (QBP) in velocity and intensity helioseismic observations. The seismic QBP over solar cycle 23Aims: We looked for signatures of quasi-biennial periodicity (QBP) over different phases of solar cycle by means of acoustic modes of oscillation. Low-degree p-mode frequencies are shown to be sensitive to changes in magnetic activity due to the global dynamo. Recently there has been reported evidence of two-year variations in p-mode frequenciesSimoniello, R. et al.
Advertised on:
32012 -
On the Solar Origin of the Signal at 220.7 μHz: A Possible Component of a g-Mode?Gravity modes in the Sun have been the object of a long and difficult search in recent decades. Thanks to the data accumulated with the last generation of instruments (BiSON, GONG, and three helioseismic instruments aboard the Solar and Heliospheric Observatory (SOHO)), scientists have been able to find signatures of their presence. However, theJiménez, A. et al.
Advertised on:
102009 -
Acoustic power absorption and enhancement generated by slow and fast MHD waves. Evidence of solar cycle velocity/intensity amplitude changes consistent with the mode conversion theoryWe used long duration, high quality, unresolved (Sun-as-a star) observations collected by the ground based network BiSON and by the instruments GOLF and VIRGO on board the ESA/NASA SOHO satellite to search for solar-cycle-related changes in mode characteristics in velocity and continuum intensity for the frequency range between 2.5 mHzSimoniello, R. et al.
Advertised on:
62010 -
Doppler tomography of transiting exoplanets: a prograde, low-inclined orbit for the hot Jupiter CoRoT-11bWe report the detection of the Doppler shadow of the transiting hot Jupiter CoRoT-11b. Our analysis is based on line-profile tomography of time-series, Keck/HIRES high-resolution spectra acquired during the transit of the planet. We measured a sky-projected, spin-orbit angle λ = 0.1° ± 2.6°, which is consistent with a very low-inclined orbit withGandolfi, D. et al.
Advertised on:
72012 -
Characterization of the HD 17156 planetary systemAims: We present data to improve the known parameters of the HD 17156 system (peculiar due to the eccentricity and long orbital period of its transiting planet) and constrain the presence of stellar companions. Methods: Photometric data were acquired for 4 transits, and high precision radial velocity measurements were simultaneously acquired withBarbieri, M. et al.
Advertised on:
82009 -
Absolute parameters of the Algol binary Z VulSpectra in the wavelength range 4230-9150 Å and the first light curves of Z Vul in the infrared J, H and K bands are presented. Our infrared JHK light curves and radial velocities, together with published radial velocity and UBV data are analyzed in order to determine a new set of stellar parameters. This allows us to determine new absoluteLazaro, C. et al.
Advertised on:
82009 -
The impact of seismicity on high angular resolution astronomy: the case of El Teide Observatory, Canary IslandsSeismicity induces ground vertical and horizontal displacements that could affect the image quality obtained by telescopes in a similar fashion than atmospheric turbulence. In this work, we study the effect of local seismicity relative to atmospheric turbulence upon the image quality of astronomical observations at El Teide observatory, CanaryEff-Darwich, Antonio et al.
Advertised on:
82008