We present the Pristine survey, a new narrow-band photometric survey focused on the
metallicity-sensitive Ca H&K lines and conducted in the Northern hemisphere with the wide …

Abstract Study Analysis Group 21 (SAG21) of NASA's Exoplanet Exploration Program
Analysis Group was organized to study the effect of stellar contamination on space-based …

We present the results of a comprehensive assessment of companions to solar-type stars. A
sample of 454 stars, including the Sun, was selected from the Hipparcos catalog with π> 40 …

While the strong anticorrelation between chromospheric activity and age has led to the
common use of the Ca ii H and K emission index (R^{\prime} _ {\mathrm {HK}\,}= L …

We present and discuss new determinations of metallicity, rotation, age, kinematics, and
Galactic orbits for a complete, magnitude-limited, and kinematically unbiased sample of 16 …

We here develop an improved way of using a rotating star as a clock, set it using the Sun,
and demonstrate that it keeps time well. This technique, called gyrochronology, derives ages …

We present time series measurements of chromospheric activity for more than 2600 main-
sequence and subgiant stars on the California Planet Search (CPS) program with spectral …

Young exoplanets are snapshots of the planetary evolution process. Planets that orbit stars
in young associations are particularly important because the age of the planetary system is …

We present the discovery of two Saturn-mass companions to HD 108147 and HD 168746.
Both belong to the lightest ever discovered planets. The minimum mass of the companion to …

Context. Atmospheric magnetic fields in stars with convective envelopes heat stellar
chromospheres, and thus increase the observed flux in the Ca ii H and K doublet. Starting …