Observational Constraints on Trojans of Transiting Extrasolar Planets

Theoretical studies predict that Trojans are likely a frequent byproduct of planet formation and evolution. We present a novel method of detecting Trojan companions to transiting extrasolar planets which involves comparing the time of central eclipse with the time of the stellar reflex velocity null. We demonstrate that this method offers the potential to detect terrestrial-mass Trojans using existing ground-based observatories. This method rules out Trojan companions to HD 209458b and HD 149026b more massive than ~13 Earth masses and \~25 Earth masses at a 99.9% confidence level. Such a Trojan would be dynamically stable, would not yet have been detected by photometric or spectroscopic monitoring, and would be unrecognizable from radial velocity observations alone. We outline the future prospects for this method, and show that the detection of a "Hot Trojan" of any mass would place a significant constraint on theories of orbital migration.Comment: 6 pages, 2 figures, 1 table, accepted to ApJL. Added references, new transiting planets to table; minor correction

THE EFFECT OF MANAGERIAL ABILITY ON FARM FINANCIAL SUCCESS

The effects of managerial ability on farm financial success are analyzed for a 1990 sample of Pennsylvania commercial dairy farms using structural latent variable techniques. Latent factors related to dairy, crop, and financial management are used with herd size to explain farm financial success, measured by net farm income. Results indicate the relative importance of each management variable toward farm financial success.Farm Management,

The Good Life: Who\u27s Practicing Healthy Life-styles?

With the birth of scientific medicine in the late 1800s, the responsibility for \u27health\u27 was increasingly removed from the individual and replaced by a dependence upon medical intervention and required public health measures. Individual responsibility was viewed largely in terms of assuring accessibility for the individual (and his/her family) to the professional health delivery system. The need for health care, therefore, was seen as episodic necessity -- not as a continuing individual responsibility

LOWER LIMB MOVEMENT VARIABILITY DURING RUGBY UNION PLACE KICKING

Place kicking accuracy has a significant impact rugby match outcomes. This project investigated the variability of the kicking leg kinematics and the consistency on the stance and kicking foot positions at ball contact in a group of seven highly proficiency kickers. Kinematic data were collected using a high speed motion capture system (500 Hz) during six simulated attempts on goal. Movement variability was assessed using Normalised Root Mean Square of the swing leg pelvis, hip and knee kinematics, and the standard deviation of the stance foot at opposite plant and kicking foot at ball contact (BC). Results suggest a strong relationship between stance foot placement, swing leg movement variability and the orientation of the kicking foot at BC. This pilot study highlighted the importance of movement variability in determining consistent foot placement at BC in place kicking

K-independent percolation on trees

Consider the class of k-independent bond, respectively site, percolations with parameter p on an infinite tree T. We derive tight bounds on p for both a.s. percolation and a.s. nonpercolation. The bounds are continuous functions of k and the branching number of T. This extends previous results by Lyons for the independent case (k=0) and by Bollob\`as & Balister for 1-independent bond percolations. Central to our argumentation are moment method bounds \`a la Lyons supplemented by explicit percolation models \`a la Bollob\`as & Balister. An indispensable tool is the minimality and explicit construction of Shearer's measure on the k-fuzz of Z.Comment: 28 pages, 4 figure

Left Recursion in Parsing Expression Grammars

Parsing Expression Grammars (PEGs) are a formalism that can describe all deterministic context-free languages through a set of rules that specify a top-down parser for some language. PEGs are easy to use, and there are efficient implementations of PEG libraries in several programming languages. A frequently missed feature of PEGs is left recursion, which is commonly used in Context-Free Grammars (CFGs) to encode left-associative operations. We present a simple conservative extension to the semantics of PEGs that gives useful meaning to direct and indirect left-recursive rules, and show that our extensions make it easy to express left-recursive idioms from CFGs in PEGs, with similar results. We prove the conservativeness of these extensions, and also prove that they work with any left-recursive PEG. PEGs can also be compiled to programs in a low-level parsing machine. We present an extension to the semantics of the operations of this parsing machine that let it interpret left-recursive PEGs, and prove that this extension is correct with regards to our semantics for left-recursive PEGs.Comment: Extended version of the paper "Left Recursion in Parsing Expression Grammars", that was published on 2012 Brazilian Symposium on Programming Language

Planet finding prospects for the Space Interferometry Mission

The Space Interferometry Mission (SIM) will make precise astrometric measurements that can be used to detect planets around nearby stars. We have simulated SIM observations and estimated the ability of SIM to detect planets with given masses and orbital periods and measure their orbital elements. We combine these findings with an estimate of the mass and period distribution of planets determined from radial velocity surveys to predict the number and characteristics of planets SIM would likely find. Our predictions are based on extrapolating the mass distribution of known extrasolar planets by up to a factor of 100. This extrapolation provides the best prediction we can make of the actual number of planets that SIM will detect and characterize, but may substantially over- or underestimate the frequency of Earth-mass planets, especially if these form by a different mechanism than giant planets. We find that SIM is likely to detect 1-5 planets with masses less than 3 M_Earth (depending on mission parameters). SIM would measure masses and orbits with 30% accuracy for 0-2 of these planets, but is unlikely to measure orbits with 10% accuracy for more than one of them. SIM is likely to detect 5-25 planets with mass less than 20 M_Earth, measure masses and orbits with 30% accuracy for 2-12 of these, and measure masses and orbits with 10% accuracy for 2-8 such planets. SIM is likely to find 25-160 planets of all masses, depending on the observing strategy and mission lifetime.Comment: 30 pages, 12 figures, submitte

Dynamical Origin of Extrasolar Planet Eccentricity Distribution

We explore the possibility that the observed eccentricity distribution of extrasolar planets arose through planet-planet interactions, after the initial stage of planet formation was complete. Our results are based on ~3250 numerical integrations of ensembles of randomly constructed planetary systems, each lasting 100 Myr. We find that for a remarkably wide range of initial conditions the eccentricity distributions of dynamically active planetary systems relax towards a common final equilibrium distribution, well described by the fitting formula dn ~ e exp[-1/2 (e/0.3)^2] de. This distribution agrees well with the observed eccentricity distribution for e > 0.2, but predicts too few planets at lower eccentricities, even when we exclude planets subject to tidal circularization. These findings suggest that a period of large-scale dynamical instability has occurred in a significant fraction of newly formed planetary systems, lasting 1--2 orders of magnitude longer than the ~1 Myr interval in which gas-giant planets are assembled. This mechanism predicts no (or weak) correlations between semimajor axis, eccentricity, inclination, and mass in dynamically relaxed planetary systems. An additional observational consequence of dynamical relaxation is a significant population of planets (>10%) that are highly inclined (>25deg) with respect to the initial symmetry plane of the protoplanetary disk; this population may be detectable in transiting planets through the Rossiter-McLaughlin effect.Comment: Accepted to ApJ, conclusions updated to reflect the current observational constraint