We present Roche tomograms of the K4V secondary star in the cataclysmic variable AE Aqr, reconstructed from two data sets taken 9 d apart, and measure the differential rotation of the stellar surface. The tomograms show many large, cool starspots, including a large high-latitude spot and a prominent appendage down the trailing hemisphere. We find

Trans-Neptunian objects (TNOs) are considered some of the most pristine objects in the Solar System. Their surfaces display a wide range of compositions, going from surfaces covered by dark irradiation mantels, to surfaces totally covered by ices. According to models of the retention of volatiles, only TNOs with a diameter d &gt 1000 km are

Last year (Campins et al. 2006), we reported near-infrared rotational variability in ground-based spectra of comet-asteroid transition object 944 Hidalgo. Since then, we carried out a rotationally resolved study of Hidalgo at mid-infrared wavelengths using the Infrared Spectrograph (IRS) on NASA's Spitzer Space Telescope. We obtained 7 to 38 micron

We report the new spectroscopic observations of the gravitational lens RXJ 021+4529 with the multi-mode focal reducer SCORPIO of the SAO RAS 6 m telescope. The new spectral observations were compared with the previously observed spectra of components A and B of RXJ 0921+4529, i.e., the same components observed in different epochs. We found a

The Visible-light Imager and Magnetograph (VIM) proposed for the ESA Solar Orbiter mission will observe a photo spheric spectral line at high spatial resolution. Here we simulate and interpret VIM measurements. Realistic MHD models are used to synthesize "observed" Stokes profiles of the photospheric Fe I 617.3 nm line. The profiles are degraded by

The SolO-VIM instrument will be a two-dimensional full-Stokes spectro-polarimeter which will provide diffraction-limited vector-magnetograms, Dopplergrams, and continuum images of the solar photosphere. The instrument's performance depends on various parameters such as aperture diameter, filter characteristics, spectral- line sampling, and orbital