Toward a homogeneous set of transiting planet parameters

With 40 or more transiting exoplanets now known, the time is ripe to seek patterns and correlations among their observed properties, which may give important insights into planet formation, structure, and evolution. This task is made difficult by the widely different methodologies that have been applied to measure their properties in individual cases. Furthermore, in many systems our knowledge of the planet properties is limited by the knowledge of the properties of the parent stars. To address these difficulties we have undertaken the first comprehensive analysis of the data for 23 transiting planets using a uniform methodology. We revisit several of the recently proposed correlations, and find new ones involving the metallicity of the parent stars.Comment: 4 pages including figures. To appear in Proceedings of IAU Symposium 253, "Transiting Planets", May 2008, Cambridge, M

A New Low-Mass Eclipsing Binary from SDSS-II

We present observations of a new low-mass double-lined eclipsing binary system discovered using repeat observations of the celestial equator from the Sloan Digital Sky Survey II. Using near-infrared photometry and optical spectroscopy we have measured the properties of this short-period [P=0.407037(14) d] system and its two components. We find the following parameters for the two components: M_1=0.272+/-0.020 M_sun, R_1=0.268+/-0.010 R_sun, M_2=0.240+/-0.022 M_sun, R_2=0.248+/-0.0090 R_sun, T_1=3320+/-130 K, T_2=3300+/-130 K. The masses and radii of the two components of this system agree well with theoretical expectations based on models of low-mass stars, within the admittedly large errors. Future synoptic surveys like Pan-STARRS and LSST will produce a wealth of information about low-mass eclipsing systems and should make it possible, with an increased reliance on follow-up observations, to detect many systems with low-mass and sub-stellar companions. With the large numbers of objects for which these surveys will produce high-quality photometry, we suggest that it becomes possible to identify such systems even with sparse time sampling and a relatively small number of individual observations.Comment: 15 Pages, 9 Figures, 6 Tables. Replaced with version accepted to Ap

Current research trends in the user experience of mobile augmented reality: Content and bibliometric mapping analysis

The aim of this work is to highlight research trends between 2015 to 2020 in the study of mobile augmented reality’s user experience by conducting a content analysis and bibliometric mapping analysis of MAR research literature. This study dissects the different research design types chosen by mobile augmented reality (MAR) authors. In addition to illuminating design types, this study also uncovers trends in data collection, sampling, and analysis. In recent years, the benefits of MAR applications have been lauded due to their ability to present information in different learning experiences. MAR applications enable the combination of virtual and real-world objects by way of superimposing digital objects and auditory triggers onto reality, providing the user with real-time interaction and feedback opportunities. MAR is unique in comparison to other augmented reality technologies in that MAR leverages an already ubiquitous hardware: the cell phone. This aspect of MAR is increasingly utilized by both educators and cultural heritage institutions to package material through interactive and innovative approaches. However, researching the user experience in MAR applications is particularly difficult due to its broad reach into many disparate fields of study. This research highlights the diversity of disciplinary perspectives and methods used in mobile augmented reality research in order to exhibit the subject areas in which its impact is greatest

BANANA IV: Two aligned stellar rotation axes in the young eccentric binary system EP Crucis: primordial orientation and tidal alignment

With observations of the EP Cru system, we continue our series of measurements of spin-orbit angles in eclipsing binary star systems, the BANANA project (Binaries Are Not Always Neatly Aligned). We find a close alignment between the sky projections of the rotational and orbital angular momentum vectors for both stars (beta_p = -1.8+-1.6 deg and |beta_s|<17 deg). We also derive precise absolute dimensions and stellar ages for this system. The EP Cru and DI Her systems provide an interesting comparison: they have similar stellar types and orbital properties, but DI Her is younger and has major spin-orbit misalignments, raising the question of whether EP Cru also had a large misalignment at an earlier phase of evolution. We show that tidal dissipation is an unlikely explanation for the good alignment observed today, because realignment happens on the same timescale as spin-orbit synchronization, and the stars in EP Cru are far from syncrhonization (they are spinning 9 times too quickly). Therefore it seems that some binaries form with aligned axes, while other superficially similar binaries are formed with misaligned axes.Comment: ApJ accepted, 10 pages, 7 figure

A Smaller Radius for the Transiting Exoplanet WASP-10b

We present photometry of WASP-10 during the transit of its short-period Jovian planet. We employed the novel PSF-shaping capabilities the OPTIC camera mounted on the UH 2.2m telescope to achieve a photometric precision of 4.7e-4 per 1.3 min sample. With this new light curve, in conjunction with stellar evolutionary models, we improve on existing measurements of the planetary, stellar and orbital parameters. We find a stellar radius Rstar = 0.698 +/- 0.012 Rsun and a planetary radius Rp = 1.080 +/- 0.020 Rjup. The quoted errors do not include any possible systematic errors in the stellar evolutionary models. Our measurement improves the precision of the planet's radius by a factor of 4, and revises the previous estimate downward by 16% (2.5sigma, where sigma is the quadrature sum of the respective confidence limits). Our measured radius of WASP-10b is consistent with previously published theoretical radii for irradiated Jovian planets.Comment: 4 pages, 2 tables, 2 figures, table 1 available upon reques

Five New Transits of the Super-Neptune HD 149026

We present new photometry of HD 149026 spanning five transits of its "super-Neptune" planet. In combination with previous data, we improve upon the determination of the planet-to-star radius ratio: R_p/R_star = 0.0491^{+0.0018}_{-0.0005}. We find the planetary radius to be 0.71 +/- 0.05 R_Jup, in accordance with previous theoretical models invoking a high metal abundance for the planet. The limiting error is the uncertainty in the stellar radius. Although we find agreement among four different ways of estimating the stellar radius, the uncertainty remains at 7%. We also present a refined transit ephemeris and a constraint on the orbital eccentricity and argument of pericenter, e cos(omega) = -0.0014 +/- 0.0012, based on the measured interval between primary and secondary transits.Comment: To appear in ApJ [19 pages

Human fertility after a disaster : a systematic literature review

Fertility is a key demographic parameter influenced by disaster. With the growing risk of disasters, interest in the fertility response to a disaster is increasing among the public, policy makers and researchers alike. As yet, a synthesis of the current evidence on how fertility changes after disaster does not exist. We reviewed 50 studies retrieved from a systematic search based on a pre-registered protocol. We found an overall negative impact of disasters on fertility. If any, increases in fertility were mostly linked with weather-related physical disasters. We also identified 13 distinct mechanisms which researchers have considered as underlying the fertility effects of disaster. By contrast to the common belief that disasters are more likely to increase fertility in contexts with already high fertility, we found little evidence to suggest that the total fertility rate of the studied populations was an important predictor of the direction, timing or size of fertility impacts. While this may be because no relationship exists, it may also be due to biases we observed in the literature towards studying high-income countries or high-cost disasters. We summarize the methodological limitations identified from the reviewed studies into six practical recommendations for future research. Our findings inform both the theories behind the fertility effects of disasters and the methods for studying them

Improved spectroscopic parameters for transiting planet hosts

We report homogeneous spectroscopic determinations of the effective temperature, metallicity, and projected rotational velocity for the host stars of 56 transiting planets. Our analysis is based primarily on the stellar parameter classification (SPC) technique. We investigate systematic errors by examining subsets of the data with two other methods that have often been used in previous studies (Spectroscopy Made Easy (SME) and MOOG). The SPC and SME results, both based on comparisons between synthetic spectra and actual spectra, show strong correlations between T [subscript eff], [Fe/H], and log g when solving for all three quantities simultaneously. In contrast the MOOG results, based on a more traditional curve-of-growth approach, show no such correlations. To combat the correlations and improve the accuracy of the temperatures and metallicities, we repeat the SPC analysis with a constraint on log g based on the mean stellar density that can be derived from the analysis of the transit light curves. Previous studies that have not taken advantage of this constraint have been subject to systematic errors in the stellar masses and radii of up to 20% and 10%, respectively, which can be larger than other observational uncertainties, and which also cause systematic errors in the planetary mass and radius

The Transit Light Curve Project. VI. Three Transits of the Exoplanet TrES-2

Of the nearby transiting exoplanets that are amenable to detailed study, TrES-2 is both the most massive and has the largest impact parameter. We present z-band photometry of three transits of TrES-2. We improve upon the estimates of the planetary, stellar, and orbital parameters, in conjunction with the spectroscopic analysis of the host star by Sozzetti and co-workers. We find the planetary radius to be 1.222 +/- 0.038 R_Jup and the stellar radius to be 1.003 +/- 0.027 R_Sun. The quoted uncertainties include the systematic error due to the uncertainty in the stellar mass (0.980 +/- 0.062 M_Sun). The timings of the transits have an accuracy of 25s and are consistent with a uniform period, thus providing a baseline for future observations with the NASA Kepler satellite, whose field of view will include TrES-2.Comment: 15 pages, including 2 figures, accepted Ap

The Zebrafish Homologue of the Human DYT1 Dystonia Gene Is Widely Expressed in CNS Neurons but Non-Essential for Early Motor System Development

DYT1 dystonia is caused by mutation of the TOR1A gene, resulting in the loss of a single glutamic acid residue near the carboxyl terminal of TorsinA. The neuronal functions perturbed by TorsinA[ΔE] are a major unresolved issue in understanding the pathophysiology of dystonia, presenting a critical roadblock to developing effective treatments. We identified and characterized the zebrafish homologue of TOR1A, as a first step towards elucidating the functions of TorsinA in neurons, in vivo, using the genetically-manipulable zebrafish model. The zebrafish genome was found to contain a single alternatively-spliced tor1 gene, derived from a common ancestral locus shared with the dual TOR1A and TOR1B paralogues found in tertrapods. tor1 was expressed ubiquitously during early embryonic development and in multiple adult tissues, including the CNS. The 2.1 kb tor1 mRNA encodes Torsin1, which is 59% identical and 78% homologous to human TorsinA. Torsin1 was expressed as major 45 kDa and minor 47 kDa glycoproteins, within the cytoplasm of neurons and neuropil throughout the CNS. Similar to previous findings relating to human TorsinA, mutations of the ATP hydrolysis domain of Torsin1 resulted in relocalization of the protein in cultured cells from the endoplasmic reticulum to the nuclear envelope. Zebrafish embryos lacking tor1 during early development did not show impaired viability, overt morphological abnormalities, alterations in motor behavior, or developmental defects in the dopaminergic system. Torsin1 is thus non-essential for early development of the motor system, suggesting that important CNS functions may occur later in development, consistent with the critical time window in late childhood when dystonia symptoms usually emerge in DYT1 patients. The similarities between Torsin1 and human TorsinA in domain organization, expression pattern, and cellular localization suggest that the zebrafish will provide a useful model to understand the neuronal functions of Torsins in vivo