Transiting Exoplanets with JWST

The era of exoplanet characterization is upon us. For a subset of exoplanets -- the transiting planets -- physical properties can be measured, including mass, radius, and atmosphere characteristics. Indeed, measuring the atmospheres of a further subset of transiting planets, the hot Jupiters, is now routine with the Spitzer Space Telescope. The James Webb Space Telescope (JWST) will continue Spitzer's legacy with its large mirror size and precise thermal stability. JWST is poised for the significant achievement of identifying habitable planets around bright M through G stars--rocky planets lacking extensive gas envelopes, with water vapor and signs of chemical disequilibrium in their atmospheres. Favorable transiting planet systems, are, however, anticipated to be rare and their atmosphere observations will require tens to hundreds of hours of JWST time per planet. We review what is known about the physical characteristics of transiting planets, summarize lessons learned from Spitzer high-contrast exoplanet measurements, and give several examples of potential JWST observations.Comment: 22 pages, 11 figures. In press in "Astrophysics in the Next Decade: JWST and Concurrent Facilities, Astrophysics & Space Science Library, Thronson, H. A., Tielens, A., Stiavelli, M., eds., Springer: Dordrecht (2008)." The original publication will be available at http://www.springerlink.co

Accessibility for Plurals in Continuation Semantics

International audienceThis paper accounts for the semantics of plurality, in particular, the accessibility relation for plural anaphoras. Two types of dis- course antecedents formations, inherited from the classical treatment [14], namely summation and abstraction, are studied in detail. Solutions for each phenomenon are provided respectively by introducing two new functions Sum and Abs, for obtaining the semantic interpretations. The technical background in this paper is based on a recently proposed dynamic semantic framework [9], which pertains a style of the traditional Montague Grammar and the principle of compositionality, without adding any new concept to classical logic

Mass nouns and plural logic

Abstract There are two main approaches to the semantics of mass nouns (cf. Bunt 1985, Pelletier & Schubert 1989). One uses sets as their semantic values, the other uses mereological sums. Both face difficult problems, notably with sentences like The gold on the table weighs seven ounces (Bunt 1985) and The clay that made up those three bowls is identical with the clay that now makes up these two statues (cf. Cartwright 1965). We propose a new theory able to solve these problems, in a framework different from predicate logic, called plural logic. Our semantics is faithful to the intuition that, if there are eight pieces of silverware on a table, the speaker refers to eight things at once when he says: The silverware that is on the table comes from Italy. 1