SOME TESTS TO ESTABLISH CONFIDENCE IN PLANETS DISCOVERED BY TRANSIT PHOTOMETRY

Increased attention is being paid to transit photometry as a viable method for discovering or confirming detections of extrasolar planets. Several ground-based efforts are underway that target short-period, giant planets such as 51 Peg b, and several missions have been proposed to NASA and ESA to detect planets as small as Earth from spaceborne photometers. The success of these efforts depends in part on the ability to establish appropriate detection thresholds to control false alarm rates and the ability to assess the statistical confidence in planetary candidates drawn from any such search. This latter function attains higher importance for the space-based efforts, where direct ground-based confirmation of terrestrial-size planets is not possible. These tasks are complicated by the need to survey tens of thousands of stars to overcome the limited geometric probability of transit alignment and by the nature of the transit signals themselves. In this paper, we present empirical methods for setting appropriate detection thresholds and for establishing the confidence level in planetary candidates obtained from transit photometry of even a large number of stars. The methods are simple and allow the observer to quickly assess the statistical significance of any particular set of transits

Trade and the Environment: Equilibrium or Imbalance?

Review of Greening the GATT: Trade, Environment, and the Future by Daniel C. Esty; Freer Trade, Protected Environment: Balancing Trade Liberalization and Environmental Interests by C.Ford Runge, François Ortalo-Magné, and Philip Vande Kamp; Trade and the Environment: The Search for Balance (James Cameron, Paul Demaret & Damien Geradin, eds.); and Trading Up: Consumer and Environmental Regulation in a Global Economy by David Voge

Singing Beetles? Figuring out how male rhinoceros beetles produce their courtship songs.

Insects produce sound in wildly-diverse ways, from the vibrating wings of chirping crickets to the pulsating tympanum of whining of cicadas. Beetles (order: Coleoptera) use sound in aggressive displays, alarm calls, and courtship sequences. Although all beetles appear to generate sounds using stridulation, where a plectrum, or pick, is rubbed against a pars stridens, or file, species differ in the size and location of these structures, resulting in a diverse mechanistic array of sound production within this order. The Japanese rhinoceros beetle, Trypoxylus dichotomus, was recently observed stridulating during courtship sequences; however, the mechanism of sound production, including the body parts involved and their fine structure, were unknown. I used videos of singing males, topical applications of nail polish to putative file structures, and light and scanning electron microscopy (SEM), to localize and characterize the stridulatory apparatus. Here, I show that the pars stridens is located on the inside apical tip of each elytron, and it is scraped by a plectrum located on the dorsal surface of the abdomen. By either pumping the abdomen forward and back, or swiping it side to side, males are able to produce two distinct types of acoustic signals. Future studies will explore the properties of the male courtship song and the details of female preference

The Kepler Pixel Response Function

Kepler seeks to detect sequences of transits of Earth-size exoplanets orbiting Solar-like stars. Such transit signals are on the order of 100 ppm. The high photometric precision demanded by Kepler requires detailed knowledge of how the Kepler pixels respond to starlight during a nominal observation. This information is provided by the Kepler pixel response function (PRF), defined as the composite of Kepler's optical point spread function, integrated spacecraft pointing jitter during a nominal cadence and other systematic effects. To provide sub-pixel resolution, the PRF is represented as a piecewise-continuous polynomial on a sub-pixel mesh. This continuous representation allows the prediction of a star's flux value on any pixel given the star's pixel position. The advantages and difficulties of this polynomial representation are discussed, including characterization of spatial variation in the PRF and the smoothing of discontinuities between sub-pixel polynomial patches. On-orbit super-resolution measurements of the PRF across the Kepler field of view are described. Two uses of the PRF are presented: the selection of pixels for each star that maximizes the photometric signal to noise ratio for that star, and PRF-fitted centroids which provide robust and accurate stellar positions on the CCD, primarily used for attitude and plate scale tracking. Good knowledge of the PRF has been a critical component for the successful collection of high-precision photometry by Kepler.Comment: 10 pages, 5 figures, accepted by ApJ Letters. Version accepted for publication

TESS Data Release Notes: Sector 18 DR25

This release note discusses the science data products produced by the Science Processing Operations Center at Ames Research Center from Sector 18 observations made with the TESS spacecraft and cameras as a means to document instrument performance and data characteristics

TESS Data Release Notes: Sector 17, DR24

This release note discusses the science data products produced by the Science Processing Operations Center at Ames Research Center from Sector 17 observations made with the TESS spacecraft and cameras as a means to document instrument performance and data characteristics

TESS Data Release Notes: Sector 20, DR27

This release note discusses the science data products produced by the Science Processing Operations Center at Ames Research Center from Sector 20 observations made with the TESS spacecraft and cameras as a means to document instrument performance and data characteristics

The Vulcan Photometer: A Dedicated Photometer for Extrasolar Planet Searches

A small CCD photometer dedicated to the detection of extrasolar planets has been developed and put into operation at Mount Hamilton, California. It simultaneously monitors 6000 stars brighter than 13th magnitude in its 49 deg2 field of view. Observations are conducted all night every clear night of the year. A single field is monitored at a cadence of eight images per hour for a period of about 3 months. When the data are folded for the purpose of discovering low-amplitude transits, transit amplitudes of 1% are readily detected. This precision is sufficient to find Jovian-size planets orbiting solar-like stars, which have signal amplitudes from 1% to 2% depending on the inflation of the planet’s atmosphere and the size of the star. An investigation of possible noise sources indicates that neither star field crowding, scintillation noise, nor photon shot noise are the major noise sources for stars brighter than visual magnitude 11.6. Over one hundred variable stars have been found in each star field. About 50 of these stars are eclipsing binary stars, several with transit amplitudes of only a few percent. Three stars that showed only primary transits were examined with high-precision spectroscopy. Two were found to be nearly identical stars in binary pairs orbiting at double the photometric period. Spectroscopic observations showed the third star to be a high mass ratio single-lined binary. On 1999 November 22 the transit of a planet orbiting HD 209458 was observed and the predicted amplitude and immersion times were confirmed. These observations show that the photometer and the data reduction and analysis algorithms have the necessary precision to find companions with the expected area ratio for Jovian-size planets orbiting solar-like stars