Eight new T4.5-T7.5 dwarfs discovered in the UKIDSS large area survey data release 1

We present eight new T4.5-T7.5 dwarfs identified in the UKIRT (United Kingdom Infrared Telescope) Infrared Deep Sky Survey (UKIDSS) Large Area Survey (LAS) Data Release 1 (DR1). In addition we have recovered the T4.5 dwarf SDSS J020742.91+000056.2 and the T8.5 dwarf ULAS J003402.77-005206.7. Photometric candidates were picked up in two-colour diagrams over 190 deg2 (DR1) and selected in at least two filters. All candidates exhibit near-infrared spectra with strong methane and water absorption bands characteristic of T dwarfs and the derived spectral types follow the unified scheme of Burgasser et al. We have found six new T4.5-T5.5 dwarfs, one T7 dwarf, one T7.5 dwarf and recovered a T4.5 dwarf and a T8.5 dwarf. We provide distance estimates which lie in the 15-85 pc range; the T7.5 and T8.5 dwarfs are probably within 25 pc of the Sun. We conclude with a discussion of the number of T dwarfs expected after completion of the LAS, comparing these initial results to theoretical simulations. © 2007 RAS

Packaging, A Communicative Medium

Functional features and graphic design are essential aspects of food packaging. Communicative requirements often define main features of modern packaging but, at the same time, communication strategies have to take into account technological potentialities of new packaging and the availability of raw materials. Every explicit or hidden feature of food packaging, which is part of the ‘integrated food product’, has to be communicated: ergonomic properties, mechanical strength, chemical properties, environmental sustainability, reusability, dietary advices, possibility of ‘intelligent’ applications with reference to the definition of remaining durability and the assessment of storage conditions, etc. All the above-mentioned factors are undoubtedly useful information to make the user aware, in spite of widespread disinformation

Composition and structure of the shallow subsurface of Ceres revealed by crater morphology

Before NASA’s Dawn mission, the dwarf planet Ceres was widely believed to contain a substantial ice-rich layer below its rocky surface. The existence of such a layer has significant implications for Ceres’s formation, evolution, and astrobiological potential. Ceres is warmer than icy worlds in the outer Solar System and, if its shallow subsurface is ice-rich, large impact craters are expected to be erased by viscous flow on short geologic timescales. Here we use digital terrain models derived from Dawn Framing Camera images to show that most of Ceres’s largest craters are several kilometres deep, and are therefore inconsistent with the existence of an ice-rich subsurface. We further show from numerical simulations that the absence of viscous relaxation over billion-year timescales implies a subsurface viscosity that is at least one thousand times greater than that of pure water ice. We conclude that Ceres’s shallow subsurface is no more than 30% to 40% ice by volume, with a mixture of rock, salts and/or clathrates accounting for the other 60% to 70%. However, several anomalously shallow craters are consistent with limited viscous relaxation and may indicate spatial variations in subsurface ice content