相关论文: Characterizing Solar Center-to-Limb Radial-Velocit…
Stellar activity is the main limitation to the detection of Earth-twins using the RV technique. Despite many efforts in trying to mitigate the effect of stellar activity using empirical and statistical techniques, it seems that we are…
We re-examine the stellar kinematics of the Solar neighbourhood in terms of the velocity of the Sun with respect to the local standard of rest. We show that the classical determination of its component V_sun in the direction of Galactic…
Semi-empirical models of the solar Chromosphere show in their emission spectrum, tomography property at millimeter, sub-millimeter, and infrared wavelengths for the center of the solar disk. In this work, we studied this property in the…
The oscillation spectra of solar-type stars may in the not-too- distant future be used to constrain certain properties of the stars. The CD diagram of large versus small frequency separations is one of the powerful tools available to infer…
High-precision radial velocity (RV) measurements are crucial for exoplanet detection and characterisation. Efforts to achieve ~10 cm/s precision have been made over the recent decades, with significant advancements in instrumentation, data…
Stellar spots may in some cases produce radial velocity (RV) signatures similar to those of exoplanets. To further investigate the impact of spots, we aim at studying the detectability of Earth mass planets in the habitable zone (HZ) of…
This document is divided in two parts. The first part deals with the radial velocities (RV) distributions for B-type stars and nebulosities observed with the VLT-GIRAFFE in the Large and Small Magellanic Clouds towards the open clusters…
Waves have long been thought to contribute to the heating of the solar corona and the generation of the solar wind. Recent observations have demonstrated evidence of quasi-periodic longitudinal disturbances and ubiquitous transverse wave…
We have investigated the possibility of inferring peculiar velocities for clusters of galaxies from the Doppler shift of scattered cosmic microwave background (CMB) photons. We find that if the core radius of the gas distribution or the…
Precision radial velocity (RV) measurements continue to be a key tool to detect and characterise extrasolar planets. While instrumental precision keeps improving, stellar activity remains a barrier to obtain reliable measurements below 1-2…
For the 451 stars of the HARPS high precision program, we study correlations between the radial-velocity (RV) variation and other parameters of the Cross Correlated Function (CCF). After a careful target selection, we found a very good…
We examine closely the solar Center-to-Limb variation of continua and lines and compare observations with predictions from both a 3-D hydrodynamic simulation of the solar surface (provided by M. Asplund and collaborators) and 1-D model…
Transit spectroscopy is one of the most commonly used techniques for exoplanet atmosphere characterisation. This technique has been used to detect ionized and neutral species in exoplanet atmospheres by comparing the observed stellar lines…
We summarize results from flux density monitoring campaigns performed with the 100 meter radio-telescope at Effelsberg and the VLA during the past 15 yrs. We briefly discuss some of the statistical properties of the rapid variability from…
Stellar activity signatures such as spots and plage can significantly limit the search for extrasolar planets. Current models of activity-induced radial velocity (RV) signals focused on the impact of temperature contrast in spots predicting…
Observations of the Rossiter-McLaughlin (RM) effect provide information on star-planet alignments, which can inform planetary migration and evolution theories. Here, we go beyond the classical RM modelling and explore the impact of a…
Science Verification (SV) data of solar observations with Atacama Large Millimeter-submillimeter Array (ALMA) telescope were released to the scientific community. Understanding the centre to limb brightness function is necessary to compare…
Massive main-sequence stars have convective cores and radiative envelopes, but also sub-surface convection zones caused by partial ionisation. However, the convective properties depend on opacity and a star's metallicity. Non-rotating 1D…
One source of noise for the Laser Interferometer Space Antenna (LISA) will be time-varying changes of the space environment in the form of solar wind particles and photon pressure from fluctuating solar irradiance. The approximate magnitude…
The hydrogen Lyman lines ( 91.2 nm < lambda < 121.6 nm) are significant contributors to the radiative losses of the solar chromosphere, and are enhanced during flares. We have shown previously that the Lyman lines observed by the Extreme…