Search

We present the data acquisition strategy and characterization procedures for the Canada-France Ecliptic Plane Survey (CFEPS), a sub-component of the Canada-France-Hawaii Telescope Legacy Survey. The survey began in early 2003 and as of summer 2005 has covered 430 square degrees of sky within a few degrees of the ecliptic. Moving objects beyond the orbit of Uranus are detected to a magnitude limit of [m.sub.R] = 23-24 (depending on the image quality). To track as large a sample as possible and avoid introducing followup bias, we have developed a multi-epoch observing strategy that is spread over several years. We present the evolution of the uncertainties in ephemeris position and orbital elements of a small 10-object sample of objects tracked through these epochs as part of a preliminary presurvey starting a year before the main CFEPS project. We describe the CFEPS survey simulator, to be released in 2006, which allows theoretical models of the Kuiper belt to be compared with the survey discoveries. The simulator utilizes the well-documented pointing history of CFEPS, with characterized detection efficiencies as a function of magnitude and rate of motion on the sky. Using the presurvey objects we illustrate the usage of the simulator in modeling the classical Kuiper belt. The primary purpose of this paper is to allow a user to immediately exploit the CFEPS data set and releases as they become available in the coming months. Keywords: Trans-neptunian objects; Kuiper belt objects

Nitrogen fertilization is a required production practice for cotton (Gossypium hirsutum L.) with risks arising from under- and over-fertilization. Tissue testing for diagnosing N deficiencies in crops can use leaf blades and the total N concentration, but this practice has not been rigorously examined in cotton. The primary objective of these experiments was to determine the leaf-N concentration of the uppermost, fully mature leaf blade below which yield loss could be expected. Nitrogen-rate field experiments were conducted at 12 research station and farm sites in the Midsouth USA in Louisiana, Arkansas, Mississippi, and Alabama in 1996 and 1997. Leaf-blade total N concentrations associated with yield loss were 4.3% N at early bloom ([R.sup.2] = 0.50) and 4.1% N at mid-bloom (3 wk after early bloom, [R.sup.2] = 0.32). The likelihood of applying N when not needed could be reduced by lowering the early bloom critical value to 3.9%. Only 4% of all samples sufficient in N would have been incorrectly diagnosed N deficient at that critical value, but 44% of all deficient samples would have been misidentified as N sufficient. Reduced yields due to over application of N were evident in some samples with leaf N between 4.6 and 4.8% at early bloom. These concentrations were also common for N-sufficient plants, making accurate diagnoses of the over application of N unlikely. Our leaf-N critical values probably differ from previously established values because earlier values were derived via survey techniques and because faster fruiting cultivars may require higher leaf N., NITROGEN FERTILIZER is used on 90% of the U.S. cotton hectareage to optimize growth and profits (Fertilizer Inst., 1998). Fertilizer N is a small expense compared with land costs or [...]

By telescopic tracking, we have established that the transneptunian object (TNO) 2000 C[R.sub.105] has a semimajor axis of 220 [+ or -] AU and perihelion distance of 44.14 [+ or -] 0.02 AU, beyond the domain which has heretofore been associated with the 'scattered disk' of Kuiper Belt objects interacting via gravitational encounters with Neptune. We have also firmly established that the TNO 1995 T[L.sub.8] has a high perihelion (of 40.08 [+ or -] 0.02 AU). These objects, and two other recent discoveries which appear to have perihelia outside 40 AU, have probably been placed on these orbits by a gravitational interaction which is not strong gravitational scattering off of any of the giant planets on their current orbits. Their existence may thus have profound cosmogonic implications for our understanding of the formation of the outer Solar System. We discuss some viable scenarios which could have produced these objects, including long-term diffusive chaos and scattering off of other massive bodies in the outer Solar System. This discovery implies that there must be a large population of TNOs in an 'extended scattered disk' with perihelia above the previously suggested 38 AU boundary. The total population is difficult to estimate due to the ease with which such objects would have been lost. This illustrates the great value of frequent and well time-sampled recovery observations of trans-neptunian objects within their discovery opposition. Key Words: Kuiper Belt objects; trans-neptunian objects; comets; dynamics.

Author(s): N. Murray [1]; M. Holman (corresponding author) [2] Observers have targeted solar-type stars in their searches for planets, partly motivated by the belief that these stars might harbour Earth-like [...]

Motivated by the discovery of the first two irregular satellites of Uranus in 1997, our team has conducted a search covering approximately 90% of the dynamically stable region around Uranus. We have discovered three additional objects moving at rates consistent with satellite orbital motion. At the end of 1999, the available observations are of sufficient quality to almost guarantee that these three new objects are bound to the planet and confirm that Uranus is host to a system of numerous, but faint and small, irregular satellites. We report a preliminary negative result in a similar search near Neptune. [C] 2000 Academic Press Key Words: satellites; Uranus; Neptune.

Classical analytic theories of the solar system indicate that it is stable, but numerical integrations suggest that it is chaotic. This disagreement is resolved by a new analytic theory. The theory shows that the chaos among the jovian planets results from the overlap of the components of a mean motion resonance among Jupiter, Saturn, and Uranus, and provides rough estimates of the Lyapunov time ([10.sup.7] years) and the dynamical lifetime of Uranus ([10.sup.18] years). The jovian planets must have entered the resonance after all the gas and most of the planetesimals in the protoplanetary disk were removed., The predictability of planetary motions was largely responsible for the acceptance of Newton's theory of gravitation. Despite this, Newton doubted the long-term stability of the solar system. Laplace noted that [...]