We present a detailed study on the surface composition of 2003 EL61. We use visible and near-infrared spectra of 2003 EL61 obtained for more than three consecutive hours covering more than 80% of the rotational period, in the Telescopio Nazionale Galileo and William Herschel Telescope, sited in the Observatorio del Roque de los Muchachos. First we

This paper describes the Fifth Data Release (DR5) of the Sloan Digital Sky Survey (SDSS). DR5 includes all survey quality data taken through 2005 June and represents the completion of the SDSS-I project (whose successor, SDSS-II, will continue through mid-2008). It includes five-band photometric data for 217 million objects selected over 8000 deg2

We present a comprehensive study of the observational dependence of the mass-loss rate in stationary stellar winds of hot massive stars on the metal content of their atmospheres. The metal content of stars in the Magellanic Clouds is discussed, and a critical assessment is given of state-of-the-art mass-loss determinations of OB stars in these two

This paper reports on our new findings from the International Time Program observations at the Canaries islands, Spain, in July 2005. We have found small-scale photospheric events with extremely red-shifted Stokes V signals in sunspot moat regions. A preliminary estimate of the physical conditions for an observed Stokes V profile indicates the

Results concerning the dependence of photometric and radial velocity amplitudes on metallicity are presented based on about 200 Galactic classical Cepheids pulsating in the fundamental mode. The Galactic distribution of the [Fe/H] value of Cepheids is also studied. We show that the photometric amplitude ratio AI/AV is independent of metallicity

The characterization of the vertical turbulence distribution on an astronomical site should be based on statistical behaviour, as it is required for other parameters in site testing. We present the statistical results of the optical-turbulence profiles at the Roque de los Muchachos and Teide observatories at the Canary Islands (Spain). The data