11,729 research outputs found

    Strengthening the ties that exist: Reexploring charted territory

    Get PDF
    published or submitted for publicationis peer reviewe

    Empirical relations for the accurate estimation of stellar masses and radii

    Get PDF
    In this work, we have taken advantage of the most recent accurate stellar characterizations carried out using asteroseismology, eclipsing binaries and interferometry to evaluate a comprehensive set of empirical relations for the estimation of stellar masses and radii. We have gathered a total of 934 stars -- of which around two-thirds are on the Main Sequence -- that are characterized with different levels of precision, most of them having estimates of M, R, Teff, L, g, density, and [Fe/H]. We have deliberately used a heterogeneous sample (in terms of characterizing techniques and spectroscopic types) to reduce the influence of possible biases coming from the observation, reduction, and analysis methods used to obtain the stellar parameters. We have studied a total of 576 linear combinations of Teff, L, g, density, and [Fe/H] (and their logarithms) to be used as independent variables to estimate M or R. We have used an error-in-variables linear regression algorithm to extract the relations and to ensure the fair treatment of the uncertainties. We present a total of 38 new or revised relations that have an adj-R2 regression statistic higher than 0.85, and a relative accuracy and precision better than 10% for almost all the cases. The relations cover almost all the possible combinations of observables, ensuring that, whatever list of observables is available, there is at least one relation for estimating the stellar mass and radius.Comment: 49 Pages, 17 figures, 11 tables, accepted for publication in ApJ

    Family migration and mobility sequences in the United States

    Get PDF
    Significant changes in family composition in the past quarter-century raise important questions about life-course outcomes embedded in these family changes, especially in relation to the migratory and mobility patterns of individuals and families. The classic distinction between long-distance/employment and short-distance/housing-related moves may be eroding. Patterns of movement appear much less dichotomous and more diverse as family structures become more diverse. Using the Panel Study of Income Dynamics this study shows that the previous research, which suggested relatively simple links between long-distance and short-distance moves, is an over-simplification. Moreover, there is much more unintended movement at both migratory and mobility scales suggesting the economic models of employment migration may be missing important family dynamics in the migration mobility process.children, family migration, households, life course, moving intentions, residential mobility, sequences

    K2P2^2 - A photometry pipeline for the K2 mission

    Full text link
    With the loss of a second reaction wheel, resulting in the inability to point continuously and stably at the same field of view, the NASA Kepler satellite recently entered a new mode of observation known as the K2 mission. The data from this redesigned mission present a specific challenge; the targets systematically drift in position on a ~6 hour time scale, inducing a significant instrumental signal in the photometric time series --- this greatly impacts the ability to detect planetary signals and perform asteroseismic analysis. Here we detail our version of a reduction pipeline for K2 target pixel data, which automatically: defines masks for all targets in a given frame; extracts the target's flux- and position time series; corrects the time series based on the apparent movement on the CCD (either in 1D or 2D) combined with the correction of instrumental and/or planetary signals via the KASOC filter (Handberg & Lund 2014), thus rendering the time series ready for asteroseismic analysis; computes power spectra for all targets, and identifies potential contaminations between targets. From a test of our pipeline on a sample of targets from the K2 campaign 0, the recovery of data for multiple targets increases the amount of potential light curves by a factor 10{\geq}10. Our pipeline could be applied to the upcoming TESS (Ricker et al. 2014) and PLATO 2.0 (Rauer et al. 2013) missions.Comment: 14 pages, 20 figures, Accepted for publication in The Astrophysical Journal (Apj

    LSE RB feature essay: populism and the limits of neoliberalism by William Davies

    Get PDF
    Coinciding with the release of a revised edition of The Limits of Neoliberalism: Authority, Sovereignty and the Logic of Competition, previously reviewed on LSE RB in 2015, William Davies argues that the recent surge in ‘populism’ must be understood in relation to the structures of political, cultural and moral economy, in particular the inability of neoliberalism to sustain the myth of a level playing field or a sense of shared reality between those who constantly ‘win’ and those who are set up to repeatedly ‘lose’
    corecore