Related papers: Measuring the Suns radial velocity variability due…
Using images from the Helioseismic and Magnetic Imager aboard the \textit{Solar Dynamics Observatory} (SDO/HMI), we extract the radial-velocity (RV) signal arising from the suppression of convective blue-shift and from bright faculae and…
Radial velocity perturbations induced by stellar surface inhomogeneities including spots, plages and granules currently limit the detection of Earth-twins using Doppler spectroscopy. Such stellar noise is poorly understood for stars other…
Magnetic activity and surface flows at different scales pertub radial velocity measurements. This affects the detectability of low-mass exoplanets. In these flows, the effect of supergranulation is not as well characterized as the other…
Context: Supergranulation is a pattern of the velocity field at the surface of the Sun, which has been known about for more than fifty years, however, no satisfactory explanation of its origin has been proposed. Aims: New observational…
Stellar radial velocities play a fundamental role in the discovery of extrasolar planets and the measurement of their physical parameters as well as in the study of stellar physical properties. We investigate the impact of the solar…
Spectrographs like HARPS can now reach a sub-m/s precision in radial-velocity (RV) (Pepe & Lovis 2008). At this level of accuracy, we start to be confronted with stellar noise produced by 3 different physical phenomena: oscillations,…
The time-variable velocity fields of solar-type stars limit the precision of radial-velocity determinations of their planets' masses, obstructing detection of Earth twins. Since 2015 July we have been monitoring disc-integrated sunlight in…
In this paper we develop an analytical expression relating the sensitivity to a periodic signal to the duration and accuracy of a given set of data. The effects of windowing are explored, and also the sensitivity to periods longer than the…
Supergranulation is a fluid-dynamical phenomenon taking place in the solar photosphere, primarily detected in the form of a vigorous cellular flow pattern with a typical horizontal scale of approximately 30--35~megameters, a dynamical…
Supergranulation on the surface of the Sun is an organized cellular flow pattern with a characteristic scale of 30 Mm. It is superficially similar to the well understood granulation that operates at the 1.5 Mm natural scale of convection,…
Context. Searching for extrasolar planets through radial velocity measurements relies on the stability of stellar photospheres. Aims. We aim at characterizing the statistical properties of magnetic activity cycles, and studying their impact…
The sunspot activity is the end result of the cyclic destruction and regeneration of magnetic fields by the dynamo action. We propose a new method to analyze the daily sunspot areas data recorded since 1874. By computing the power spectral…
We present an analysis of Sun-as-a-star observations from four different high-resolution, stabilized spectrographs -- HARPS, HARPS-N, EXPRES, and NEID. With simultaneous observations of the Sun from four different instruments, we are able…
The Sun is the only star where the superficial turbulent convection can be observed at very high spatial resolution. The Solar Dynamics Observatory (SDO) has continuously observed the full Sun from space with multi-wavelength filters since…
We present the initial results of an observational study into the variation of the dominant length-scale of quiet solar emission: supergranulation. This length-scale reflects the radiative energy in the plasma of the upper solar…
Sun-like stars show intensity fluctuations on a number of time scales due to various physical phenomena on their surfaces. These phenomena can convincingly be studied in the frequency spectra of these stars - while the strongest signatures…
Solar supergranulation plays an important role in generating and structuring the solar magnetic field and as a mechanism responsible for the 11-year solar cycle. It is clearly detected within SOHO/MDI Dopplergrams, from which a variety of…
The solar magnetic activity cycle is responsible for periodic episodes of severe space weather, which can perturb satellite orbits, interfere with communications systems, and bring down power grids. Much progress has recently been made in…
Observations of quiet Sun from the Solar Optical Telescope/Spectro-Polarimeter (SOT/SP) aboard the Hinode spacecraft would reveal the magnetic characters of the solar photosphere. By making use of the deep mode observations of three quiet…
The Sun has a steady 11-year cycle in magnetic activity most well-known by the rising and falling in the occurrence of dark sunspots on the solar disk in visible bandpasses. The 11-year cycle is also manifest in the variations of emission…