Warm Cores around Regions of Low-Mass Star Formation

Warm cores (or hot corinos) around low-mass protostellar objects show a rich chemistry with strong spatial variations. This chemistry is generally attributed to the sublimation of icy mantles on dust grains initiated by the warming effect of the stellar radiation. We have used a model of the chemistry in warm cores in which the sublimation process is based on extensive laboratory data; these data indicate that sublimation from mixed ices occurs in several well-defined temperature bands. We have determined the position of these bands for the slow warming by a solar-mass star. The resulting chemistry is dominated by the sublimation process and by subsequent gas-phase reactions; strong spatial and temporal variations in certain molecular species are found to occur, and our results are, in general, consistent with observational results for the well-studied source IRAS 16293-2422. The model used is similar to one that describes the chemistry of hot cores. We infer that the chemistry of both hot cores and warm cores may be described by the same model (suitably adjusted for different physical parameters).Comment: 11 pages, 5 figures, 2 tables. Accepted by MNRA

Creative small settlements. Culture-based solutions for local sustainable development.

Culture can play a fundamental role in fostering sustainable patterns of urban and regional development. This is the message of the Global Report ‘Culture for Sustainable Urban Development’, which UNESCO has coordinated for the UN-HABITAT III Conference (Quito, October 2016). The Global Report shows that a promising culture-based vision of urban development is flourishing in different forms in several cities across the world. Even small and medium settlements located at the periphery of large cities or within their metropolitan areas, and normally associated with marginalisation or deprivation, have the potential to fully utilise their cultural resources, in both tangible (urban and architectural heritage, cultural infrastructure, etc.) and intangible form (skills, knowledge, competencies). However these small settlements, and their respective communities, require different analytical tools in order to understand their complexity and ad hoc policies to manage their assets in sustainable forms. This research report aims to show ways to understand culture and creativity in small settlements, by collecting a series of international case studies that form the backbone of the chapter 10 of the UNESCO Global Report on urban-rural linkages and titled 'Culture as a tool to achieve harmonious territorial development'. This can allow a wider dissemination of the theoretical underpinnings and the comparative findings of a research conducted during 2015 and 2016 by several research units all over the world

Near-arcsecond resolution observations of the hot corino of the solar type protostar IRAS 16293-2422

Complex organic molecules have previously been discovered in solar type protostars, raising the questions of where and how they form in the envelope. Possible formation mechanisms include grain mantle evaporation, interaction of the outflow with its surroundings or the impact of UV/X-rays inside the cavities. In this Letter we present the first interferometric observations of two complex molecules, CH3CN and HCOOCH3, towards the solar type protostar IRAS16293-2422. The images show that the emission originates from two compact regions centered on the two components of the binary system. We discuss how these results favor the grain mantle evaporation scenario and we investigate the implications of these observations for the chemical composition and physical and dynamical state of the two components.Comment: 5 pages (apjemulate), 2 figures; accepted by ApJ