Substellar objects (mass M < 0.075 Msol) have core temperatures too low to produce stable hydrogen fusion. Therefore, they progressively contract and cool down. Hundreds of brown dwarfs (M=0.013-0.075 Msol) and fewer hundreds of planetary-mass objects (M<0.013 M) or candidates have been discovered in the last fifteen years. Brown dwarfs have been

La formación y evolución de galaxias dependen fuertemente de la metalicidad y la tasa de formación estelar (SFR), por lo que el vínculo entre estos dos parámetros a diferentes desplazamientos al rojo (z) afectará sustancialmente la evolución de las galaxias. Paradójicamente, en la literatura abundan los estudios de evolución a z altos, mientras que

We observed the black hole candidate XTE J1752-223 (ATel #2258) with the William Herschel Telescope (WHT) and the ACAM imager/spectrograph at the Observatorio del Roque de los Muchachos, La Palma, Spain. 200-s exposures were taken in the R and I bands under photometric conditions and 0.6-0.7-arcsec seeing on Aug 24.887 and Aug 24.893, respectively

We have been regularly monitoring the outburst decay of the black hole candidate X-ray binary XTE J1752-223 (discovered by RXTE; ATel #2258) with the 2-m Faulkes Telescopes North and South (located at Haleakala on Maui and Siding Spring, Australia, respectively). Exposures in B, V, R and i'-bands (mostly 100-sec exposures each) were taken every ~ 3

The dust ejecta of Main-Belt Comet P/2010 A2 (LINEAR) have been observed with several telescopes at the Observatorio del Roque de los Muchachos on La Palma, Spain. Application of an inverse dust tail Monte Carlo method to the images of the dust ejecta from the object indicates that a sustained, likely water-ice-driven, activity over some eight

We present colour transformations from Two Micron All Sky Survey (2MASS) photometric system to Johnson-Cousins system and to Sloan Digital Sky Survey (SDSS) system for late-type giants and vice versa. The giant star sample was formed using surface gravity constraints ({2 log g ≤ 3}) to Cayrel de Strobel et al.' s (2001) spectroscopic catalogue