Yearslong time series of high-precision brightness measurements have been assembled for
thousands of stars with telescopes operating in space. Such data have allowed astronomers …

The Gaia mission has provided an invaluable wealth of astrometric data for more than a
billion stars in our Galaxy. The synergy between Gaia astrometry, photometry, and …

The mantra “know thy star, know thy planet” has proven to be very important for many
aspects of exoplanet science. Here I review how stellar abundances inform our …

Stellar members of binary systems are formed from the same material, and therefore they
should be chemically identical. However, recent studies have unveiled chemical differences …

Magnetic fields and stellar spots can alter the equivalent widths of absorption lines in stellar
spectra, varying during the activity cycle. This also influences the information that we derive …

Dynamical evolution within planetary systems can cause planets to be engulfed by their host
stars. Following engulfment, the stellar photosphere abundance pattern will reflect accretion …

Aims. Previous high-precision studies of abundances of elements in solar twin stars are
extended to a wider metallicity range to see how the trends of element ratios with stellar age …

Context. Exoplanetary properties strongly depend on stellar properties: to know the planet
with accuracy and precision it is necessary to know the star as accurately and precisely as …

Planet engulfment can be inferred from enhancement of refractory elements in the
photosphere of the engulfing star following accretion of rocky planetary material. Such …

Binary star systems are assumed to be co-natal and coeval, and thus to have identical
chemical composition. In this work, we aim to test the hypothesis that there is a connection …