Determination of the mass-ratio distribution, II: double-lined spectroscopic binary stars

The application of the Richardson-Lucy iterative technique for the rectification of measurement errors, to the mass-ratio distribution of the double-lined spectroscopic binary stars (sbii) intheSixth Catalogue of the Orbital Elements of Spectroscopic Binary Stars, is evaluated for the sbii systems in the Eighth version of the Catalogue. The estimates of the real distribution, produced by the Richardson-Lucy method after successive iterations, do not converge in a trivial way. The stop criterion, suggested in the original paper on the method, is used in the application of the method to both real and simulated distributions. It is shown that, in the application to the mass-ratio distribution of the sbii systems, the iterations should stop considerably earlier than was previously assumed. The enhanced peak at mass-ratios near unity, that was found to exist in the real mass-ratio distribution, based on the earlier application of the iterative technique to the sbii systems, is likely to be due to an overshoot effect that occurs when the iterations are carried too far. When the stop criterion is used in the application of the method to the sbii systems in the Eighth version of the Catalogue, the resulting estimate of the real mass-ratio distribution does not show evidence for an enhanced number of binary stars with mass ratios near unity

An electronic submission service for Astronomy and Astrophysics

This paper outlines an Electronic Submission Service (ess) for Astron- omy and Astrophysics, suitable for all parts of the journal: Letters, Main Journal, andSupplements. The proposed service should be run by a pro- fessional entity: one of the publishers, eso, thecds, orsome other, yetto be decided, party. The ess is a fully automated service, requiring minimal technical skills from authors, and editorial staff. After its initial development, testing, and implementation, the ess should run largely unattended, and require minimal maintenance. The ess is designed to support the editorial process, by allowing sub- mission of manuscripts and graphical material through email, ftp, and Web uploads. Theess subsequently processes the (L A T E X) manuscript, producing PostScript and pdf versions of the paper. These are made ac- cessible to authors, editors, and referees, by placing them in a password protected area of the Web site, associated with the ess. Oncompletion of these steps, the ess automatically informs the editorial office, by email, of the newly arrived submission. Finding and consulting an appropriate referee require the intervention of the editors, who will do most of their correspondence via email. Once a referee is found, (s)he may access the paper at the ess Web site, using the password provided by the editor. The service, as proposed here, is inspired by the electronic submis- sion schemes employed by the American Astronomical Society for The Astrophysical Journal, and the Los Alamos National Laboratory for their E-Print archive

Statistical properties of spectroscopic binary stars

As part of a study of the mass-ratio distribution of spectroscopic binary stars, the statistical properties of the systems in the Eighth Catalogue of the Orbital Elements of Spectroscopic Binary Stars, compiled by Batten et al. (1989), are investigated. Histograms are presented of the distributions of various parameters of the systems in the Catalogue as a whole, and compared to those of the previous edition. Histograms of binaries of various spectral types are presented. It is noticed that the early-type binaries in the Catalogue have on average higher radial-velocity am- plitudes, shorter periods, and smaller semi-major axes than late-type binaries. Late- type binaries have relatively more eccentric orbits. Whether the differences noticed between the early- and late-type binaries have any significance with respect to the population of binary stars in the Galaxy is not clear, because it is very hard to assess the extent to which the Catalogue is a statistically representative and complete sample. The distribution of semi-major axes a1 sin i varies considerably among different sub-samples. The mass-ratio distribution of single-lined spectroscopic binaries is, for all (sub-)samples, characterized by a decrease in the number of systems according to a power law as q --> 1, for q = Msec/Mprim > 0.25. The mass-ratio distribution of double-lined spectroscopic binaries (sbii) is, for all (sub-)samples but one, characterized by an increase in numbers according to a power law, as q --> 1. The exception to this general behaviour is the sample of sbii systems with magnitudes m < 5 m , which has its maximum at q = 0:65. The distributions are presented `as they are', without corrections for selection effects

The Mass-Ratio Distribution of Visual Binary Stars

The selection effects that govern the observations of Visual Binary Stars are in- vestigated, in order to obtain a realistic statistical distribution of the mass-ratio q = Msec=Mprim. To this end a numerical simulation programme has been developed, which `generates' binary stars and `looks' at them to determine whether an observer on Earth would be able to detect them. The simulations show that for mass-ratios q >0:35, observations are expected to reveal the real q{distribution, while for mass- ratios q <0:35 selection effects begin to play a major part. It is found that the observed mass-ratio distribution for main-sequence systems, derived from the Index Catalogue of Visual Binary Stars (ids), can be explained by a distribution of sec- ondary masses according to the Initial Mass Function (imf), i.e. ø(M) a M- 2:7 . From the Fourth Catalogue of Orbits of Visual Binary Stars (ovb) authors find a q{distribution that peaks strongly for q{values close to q = 1. Itisshownthat this mass-ratio distribution may be the result of a sampling selection effect. Due to this sampling selection effect, the ovb is a considerably more biased sample of the binary population in our Galaxy than the ids. Numerical simulations of biased sampling show that the q{distribution, found from the ovb, is not incompatible with the distribution of secondary masses according to the imf (for q >0:35), found from the ids. Because of the selection effects, it is difficult to establish the real q{distribution for q <0:35. If the real q{distribution departs from ø(q) a q^(-2,7) for q < 0,35, about 36% of all stars are in visual binaries (i.e. if the q{distribution is assumed to be at for 0 < q<0,35); if the distribution attens for q < 0,25, about 60% of the stars must be primaries of visual binaries

Flow, skilled coping and the sovereign subject

According to Dreyfus and Dreyfus (1986), skilled coping in sport occurs when an athlete reaches an expert level and can execute a sport skill on ‘automatic-pilot’, in a state of ‘flow’. In this paper we reframe phenomenological accounts of sport that try to depict flow-states as part of an athlete’s competency framework. We do so from the point of view of post-structural and post-phenomenological scholars such as Jacques Derrida’s deconstructive work on sovereignty and Jean-Luc Nancy’s (2000, 2008) ontological vantage of ‘being-with’. This lens pushes us to challenge phenomenological accounts of sport such as skilled coping and flow that, we argue, portray zombie-like performances as optimal. We suggest that such a phenomenological account of sport is not only impoverished as Breivik (2007, 2009) has argued, but also misses the very promising aspects of sport that can generate the possibility for creative and relational experiences. In making this claim we aim to reorient sport philosophy’s uptake of phenomenology toward a relational ethics