Context. Detailed chemical abundances of volatile and refractory elements have been discussed in the context of terrestrial-planet formation during in past years. Aims: The HARPS-GTO high-precision planet-search program has provided an extensive database of stellar spectra, which we have inspected in order to select the best-quality spectra

As of today, hundreds of extrasolar planets have been discoverd, and thousands of candidates are waiting for confirmation. Although we already have discovered dozens of the least massive planets (the so called super-Earths), only a few have been found to be orbiting low mass stars, and only one that actually transist a bright M star. Here, we

The first L subdwarf was a discovered only ten years ago. Less than ten L subdwarfs been published in the literature to date. Metal-poor ultracool atmospheres has not been well understood. Halo mass function cross substellar limit has not been measured. We used UKIDSS and SDSS to search for L subdwarfs. We have confirmed some new L subdwarfs and

We present new z- and H-band photometry and proper motion measurements for the five candidate very-low-mass T-type objects we recently proposed to be members of the nearest OB association with the Sun, Upper Scorpius (USco). These new data fail to corroborate our prior conclusions regarding their spectral types and affiliation with the USco

We present tests carried out on optical and infrared stellar spectra to evaluate the accuracy of different types of interpolation. Both model atmospheres and continuum normalized fluxes were interpolated. In the first case, we used linear interpolation, and in the second linear, cubic spline, cubic Bezier and quadratic Bezier methods. We generated

Understanding the spectral and photometric variability of the Earth and the rest of the solar system planets has become of utmost importance for the future characterization of rocky exoplanets. As this is not only interesting at present times but also along the planetary evolution, we studied the effect that the evolution of microbial mats and