Recent studies of the near-infrared (NIR) properties of dwarf irregular galaxies (dIs) and blue compact dwarfs (BCDs) have provided improved estimates for the NIR luminosity of old stellar populations in these galaxies. These can be used to derive gas fractions, and thereby to evaluate how BCDs have evolved with respect to dIs. Oxygen abundances

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In this paper we describe three lines of work that are being developed in the framework of the Spanish Virtual Observatory.

We present the analysis of the photometric and spectroscopic properties of a sample of 29 low redshift (z 0.6) QSOs for which both HST WFPC2 optical images and ultraviolet HST FOS spectra are available. For each object we measure the R band absolute magnitude of the host galaxy, the C IV (1550 Å) line width and the 1350 Å continuum luminosity

The present paper provides a general overview of the asteroseismic potential of δ Scuti stars in clusters, in particular focusing on convection diagnostics. We give a summarise of the last results obtained by the authors for the Praesepe cluster of which five δ Scuti stars are analysed. In that work, linear analysis is confronted with observations

Main Belt Comets (MBCs) are objects of the main belt with observed sporadic cometary-like activity (Hsieh and Jewitt 2006, Science, 312, 561). The study of asteroids that present sporadic cometary activity is of fundamental importance to address several astronomical problems including the end states of comet nuclei, the abundance of water in main