Related papers: A simple method to estimate radial velocity variat…
The Planetary Transits and Oscillations of stars mission (PLATO) will allow us to measure surface rotation and monitor photometric activity of tens of thousands of main sequence solar-type and subgiant stars. This paper is the first of a…
Spectra of composite systems (e.g., spectroscopic binaries) contain spatial information that can be retrieved by measuring the radial velocities (i.e., Doppler shifts) of the components in four observations with the slit rotated by 90…
Usually, the determination of radial velocities of stars relies on the shift of spectral lines by the Doppler effect. Russel & Atkinson (1931) and Oort (1932) already noted that due to the large proper motion and parallax of the white dwarf…
The Sun and stars with low magnetic activity levels, become photometrically brighter when their activity increases. Magnetically more active stars display the opposite behaviour and get fainter when their activity increases. We reproduce…
Exoplanet detection with precise radial velocity (RV) observations is currently limited by spurious RV signals introduced by stellar activity. We show that machine learning techniques such as linear regression and neural networks can…
Stellar variability is a key obstacle in reaching the sensitivity required to recover Earth-like exoplanetary signals using the radial velocity (RV) detection method. To explore activity signatures in Sun-like stars, we present SolAster, a…
Photospheric velocities and stellar activity features such as spots and faculae produce measurable radial velocity signals that currently obscure the detection of sub-meter-per-second planetary signals. However, photospheric velocities are…
We present a new method for determining the location of active bands of latitude on solar-type stars, which uses stellar-cycle-induced frequency shifts of detectable solar-like oscillations. When near-surface activity is distributed in a…
This paper presents a list of suggested stars for radial velocity measurements. We explain here in brief the research project for which the radial velocity of the "slow movers" i.e. small proper motion stars are necessary. Basing on this…
State of the art radial velocity (RV) exoplanet searches are limited by the effects of stellar magnetic activity. Magnetically active spots, plage, and network regions each have different impacts on the observed spectral lines, and…
Precise exoplanet characterization requires precise classification of exoplanet host stars. The masses of host stars are commonly estimated by comparing their spectra to those predicted by stellar evolution models. However,…
We report the direct imaging detection of a low-mass companion to a young, moderately active star V450 And, that was previously identified with the radial velocity method. The companion was found in high-contrast images obtained with the…
We present a radial velocity analysis of 20 solar neighborhood RR Lyrae and 3 Population II Cepheids variables. We obtained high-resolution, moderate-to-high signal-to-noise ratio spectra for most stars and obtained spectra were covering…
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…
The star HD 219542 B has been reported by us (Desidera et al. 2003) to show low-amplitude radial velocity variations that could be due to the presence of a Saturn-mass planetary companion or to stellar activity phenomena. In this letter we…
Current exoplanet surveys using the radial velocity (RV) technique are targeting M dwarfs because any habitable zone terrestrial-mass planets will induce a high RV and orbit on shorter periods than for more massive stars. One of the main…
We introduce our Radial Velocity Survey for Planets around Young stars (RVSPY), characterise our target stars, and search for substellar companions at orbital separations smaller than a few au from the host star. We use the FEROS…
The CoRoT satellite has made available high precision photometric observations of a large number of stars of different spectral types. Continuous photometric time series allow the characterization of stellar microvariability in a systematic…
The photometric time series of solar-like stars can exhibit rotational modulation due to active regions co-rotating with the stellar surface, allowing us to constrain stellar rotation and magnetic activity. In this work we investigate the…
Stellar activity, such as starspots, can induce radial velocity (RV) variations that can mask or even mimic the RV signature of orbiting exoplanets. For this reason RV exoplanet surveys have been unsuccessful when searching for planets…