Predicting Stellar Angular Sizes

Reliable prediction of stellar diameters, particularly angular diameters, is a useful and necessary tool for the increasing number of milliarcsecond resolution studies being carried out in the astronomical community. A new and accurate technique of predicting angular sizes is presented for main sequence stars, giant and supergiant stars, and for more evolved sources such as carbon stars and Mira variables. This technique uses observed $K$ and either $V$ or $B$ broad-band photometry to predict V=0 or B=0 zero magnitude angular sizes, which are then readily scaled to the apparent angular sizes with the $V$ or $B$ photometry. The spread in the relationship is 2.2% for main sequence stars; for giant and supergiant stars, 11-12%; and for evolved sources, results are at the 20-26% level. Compared to other simple predictions of angular size, such as linear radius-distance methods or black-body estimates, zero magnitude angular size predictions can provide apparent angular sizes with errors that are 2 to 5 times smaller.Comment: 28 pages, 4 figures, accepted by PAS

Waiting Longer Before Claiming, and Activating Youth: No Point?

In Belgium school-leavers are entitled to unemployment benefits after a waiting period and eligible to intensified counselling and training in the Youth Work Plan (YWP) if a job is not found within three months. The length of the waiting period and eligibility to the YWP are sharply determined by two distinct age thresholds. These are exploited to estimate the impact of these policies on the transition rate to employment and on the quality of work. Both policies increase job finding only slightly and insignificantly. The accepted wage is unaffected, but the number of working days falls and, hence, also earnings

Directly Determined Linear Radii and Effective Temperatures of Exoplanet Host Stars

We present interferometric angular sizes for 12 stars with known planetary companions, for comparison with 28 additional main-sequence stars not known to host planets. For all objects we estimate bolometric fluxes and reddenings through spectral energy distribution fits, and in conjunction with the angular sizes, measurements of effective temperature. The angular sizes of these stars are sufficiently small that the fundamental resolution limits of our primary instrument, the Palomar Testbed Interferometer, are investigated at the sub-milliarcsecond level and empirically established based upon known performance limits. We demonstrate that the effective temperature scale as a function of dereddened $(V-K)_0$ color is statistically identical for stars with and without planets. A useful byproduct of this investigation is a direct calibration of the $T_{\rm EFF}$ scale for solar-like stars, as a function of both spectral type and $(V-K)_0$ color, with an precision of $\bar{\Delta T}_{\rm {(V-K)}_0} = 138$K over the range $(V-K)_0=0.0-4.0$ and $\bar{\Delta T}_{\rm {SpType}} = 105$K for the range F6V -- G5V. Additionally, we provide in an appendix spectral energy distribution fits for the 166 stars with known planets which have sufficient photometry available in the literature for such fits; this derived "{\tt XO-Rad}" database includes homogenous estimates of bolometric flux, reddening, and angular size.Comment: Accepted for publication in Ap

No News is Good News, or the Appeal of Controversy

One of the strategies journalists use to attract their audience towards a news item is the suggestion of controversy. The terms by which issues are created influences the way discussions evolve. I will examine how such controversies can be part of an argumentative situation, and I will examine whether any evaluation standard can be developed in this matter. The style figure antithesis, as it is explored in Jeanne Fahnestock’s work, is a useful tool in considering invention, form and function of controversy and opposition

Playing with Oppositions. Verbal and visual antithesis in the media.

The inventive, argumentative and stylistic possibilities generated by the figures in general and the figure antithesis in particular are explored by Jeanne Fahnestock in the field of science. These ideas on the possibilities of antithesis I will develop in the analysis of some cases of this figure in the media. I will try to describe, analyse and evaluate how textual and/or visual pairs that form an antithesis are pushed into more, less, or a different opposition