We study how the regolith properties affect the measured fluorescent soft X-ray spectra from atmosphereless planetary surfaces as a function of mean particle size and particle size distribution, surface roughness and viewing geometry. The relative fluorescent elemental line intensities from the X-ray spectra measured from a planetary surface can be

Transiting extrasolar planets constitute only a small fraction of the range of stellar systems found to display periodic, shallow dimmings in wide-field surveys employing small-aperture camera arrays. Here we present an efficient selection strategy for follow-up observations, derived from analysis of the light curves of a sample of 67 SuperWASP

Aims:We aim to identify the nature of several objects previously catalogued as ultra-luminous X-ray (ULX) source candidates. Methods: Long-slit spectroscopy of the optical counterparts has been carried out. Results: The eight objects are at higher redshift than their putative parent galaxies. Conclusions: It is found that these eight previously

Precision measurements by the Alpha Magnetic Spectrometer on the International Space Station of the primary cosmic-ray electron flux in the range 0.5 to 700 GeV and the positron flux in the range 0.5 to 500 GeV are presented. The electron flux and the positron flux each require a description beyond a single power-law spectrum. Both the electron

FRIDA will be a common-user near infrared imager and integral field spectrograph covering the wavelength range from 0.9 to 2.5 microns. Primary observing modes driven the instrument design are two: direct imaging and integral field spectroscopy. FRIDA will be installed at the Nasmyth-B platform of the Gran Telescopio Canarias (GTC) behind the GTC

High-resolution spectra of the program stars were obtained during the period 2002 December-2004 June at the Harlan J. Smith 2.7-m telescope of the W.J. McDonald Observatory, using the 2dcoude echelle spectrometer with a 2048x2048 Tektronix CCD as detector. (2 data files).