Integrated spectroscopy is the method of choice for deriving the ages of unresolved stellar systems. However, hot stellar evolutionary stages, such as hot horizontal branch stars and blue straggler stars (BSSs), can affect the integrated ages measured using Balmer lines. Such hot, ``noncanonical'' stars may lead to overestimation of the temperature

The analysis of the Hanle effect in solar molecular lines allows us to obtain empirical information on hidden, mixed-polarity magnetic fields at subresolution scales in the (granular) upflowing regions of the ``quiet'' solar photosphere. Here we report that collisions seem to be very efficient in depolarizing the rotational levels of MgH lines

Novel spectropolarimetric observations of the He I multiplet are used to explore the dynamics of the chromospheric oscillation above sunspot umbrae. The results presented here provide strong evidence in support of the two-component model proposed by Socas-Navarro and coauthors. According to this model, the waves propagate only inside channels of

We present optical and near-IR linear polarimetry of V404 Cyg during its 2015 outburst and in quiescence. We obtained time-resolved r'-band polarimetry when the source was in outburst, near-IR polarimetry when the source was near quiescence and multiple waveband optical polarimetry later in quiescence. The optical-to-near-IR linear polarization

We present observational evidence of apparent plasma rotational motions in the feet of a solar prominence. Our study is based on spectroscopic observations taken in the He I 1083.0 nm multiplet with the Tenerife Infrared Polarimeter attached to the German Vacuum Tower Telescope. We recorded a time sequence of spectra with 34 s cadence placing the

An increasing number of both photometric and spectroscopic observations over the last decade have shown the existence of distinct sub-populations in some Galactic globular clusters. This evidence severely challenges the paradigm of globular clusters as the prototypes of single, simple stellar populations. In this review, we briefly summarise the