We present a comparison of the lithium abundances of stars with and without planetary-mass companions. New lithium abundances are reported in 79 planet hosts...
Lithium in the globular cluster NGC 6397. Evidence for dependence on evolutionary status
Context: Most globular clusters are believed to host a single stellar population. They can thus be considered a good place to study the Spite plateau and to...
Lithium in the Hyades L5 brown dwarf 2MASS J04183483+2131275
Aims: From the luminosity, effective temperature and age of the Hyades brown dwarf 2MASS J04183483+2131275 (2M0418), substellar evolutionary models predict a...
Long term photometric monitoring with the Mercator telescope. Frequencies and mode identification of variable O-B stars
Aims: We selected a large sample of O-B stars that were considered as (candidate) slowly pulsating B, β Cep, and Maia stars after the analysis of their...
Long-term evolution of three light bridges developed on the same sunspot
One important feature of sunspots is the presence of light bridges. These structures are elongated and bright (as compared to the umbra) features that seem to...
Context. The BL Lac object 1ES 0647+250 is one of the few distant γ-ray emitting blazars detected at very high energies (VHEs; ≳100 GeV) during a non-flaring...
Long-term multi-wavelength variability and correlation study of Markarian 421 from 2007 to 2009
Aims: We study the multi-band variability and correlations of the TeV blazar Mrk 421 on year timescales, which can bring additional insight on the processes...
Long-term optical spectral monitoring of a changing-look active galactic nucleus NGC 3516. II. Broad-line profile variability
Context. We analyze the broad Hβ line profile variability of a "changing look" active galactic nucleus (CL-AGN) NGC 3516 over an extensive period of 25 years...
Long-term photometric monitoring with the Mercator telescope. Frequencies and multicolour amplitudes of γ Doradus stars
Context: γ Dor stars are excellent targets for asteroseismology since the gravity modes present in these stars probe the deep stellar interiors. Mode...