49,256 research outputs found

    WRI's Governance Strategy, 2016-2020

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    Transparent, effective, accountable governance is critical to ensuring that development benefits people and the planet. The Governance Center of Excellence works with civil society, governments, development agencies, businesses, and other institutions to improve decision-making processes and legal frameworks. Our goal is to empower people and strengthen institutions to foster environmentally sound and socially equitable decision-making.In many countries, citizens and communities face social and environmental injustices that can leave them without a say in the development decisions that affect their lives and the resources they depend on.As a global leader on environmental governance, the Governance Center uses data and research to institutionalize fundamental democratic principles - such as transparency, participation, and accountability - into decision-making processes, policies, and legal frameworks. The Governance Center is divided into five practice areas—climate resilience, environmental democracy, energy governance, natural resource governance and urban governance— where our work is concentrated on six priority issues: climate, energy, food, forests, water, and cities

    Pushing the precision limit of ground-based eclipse photometry

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    Until recently, it was considered by many that ground-based photometry could not reach the high cadence sub-mmag regime because of the presence of the atmosphere. Indeed, high frequency atmospheric noises (mainly scintillation) limit the precision that high SNR photometry can reach within small time bins. If one is ready to damage the sampling of his photometric time-series, binning the data (or using longer exposures) allows to get better errors, but the obtained precision will be finally limited by low frequency noises. To observe several times the same planetary eclipse and to fold the photometry with the orbital period is thus generally considered as the only option to get very well sampled and precise eclipse light curve from the ground. Nevertheless, we show here that reaching the sub-mmag sub-min regime for one eclipse is possible with a ground-based instrument. This has important implications for transiting planets characterization, secondary eclipses measurement and small planets detection from the ground.Comment: Transiting Planets Proceeding IAU Symposium No.253, 2008. 7 pages, 4 figure

    The DWARF project: Eclipsing binaries - precise clocks to discover exoplanets

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    We present a new observational campaign, DWARF, aimed at detection of circumbinary extrasolar planets using the timing of the minima of low-mass eclipsing binaries. The observations will be performed within an extensive network of relatively small to medium-size telescopes with apertures of ~20-200 cm. The starting sample of the objects to be monitored contains (i) low-mass eclipsing binaries with M and K components, (ii) short-period binaries with sdB or sdO component, and (iii) post-common-envelope systems containing a WD, which enable to determine minima with high precision. Since the amplitude of the timing signal increases with the orbital period of an invisible third component, the timescale of project is long, at least 5-10 years. The paper gives simple formulas to estimate suitability of individual eclipsing binaries for the circumbinary planet detection. Intrinsic variability of the binaries (photospheric spots, flares, pulsation etc.) limiting the accuracy of the minima timing is also discussed. The manuscript also describes the best observing strategy and methods to detect cyclic timing variability in the minima times indicating presence of circumbinary planets. First test observation of the selected targets are presented.Comment: 12 pages, 2 figures, submitted to Astron. Nachrichte

    Climate-Energy Sinks and Sources: Paris Agreement and Dynamic Federalism

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    Systematicity and surface similarity in the development of analogy

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    In split page format (number of pages: 45)Includes bibliographical reference

    High-Cadence, High-Contrast Imaging for Exoplanet Mapping: Observations of the HR 8799 Planets with VLT/SPHERE Satellite Spot-Corrected Relative Photometry

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    Time-resolved photometry is an important new probe of the physics of condensate clouds in extrasolar planets and brown dwarfs. Extreme adaptive optics systems can directly image planets, but precise brightness measurements are challenging. We present VLT/SPHERE high-contrast, time-resolved broad H-band near-infrared photometry for four exoplanets in the HR 8799 system, sampling changes from night to night over five nights with relatively short integrations. The photospheres of these four planets are often modeled by patchy clouds and may show large-amplitude rotational brightness modulations. Our observations provide high-quality images of the system. We present a detailed performance analysis of different data analysis approaches to accurately measure the relative brightnesses of the four exoplanets. We explore the information in satellite spots and demonstrate their use as a proxy for image quality. While the brightness variations of the satellite spots are strongly correlated, we also identify a second-order anti-correlation pattern between the different spots. Our study finds that PCA-based KLIP reduction with satellite spot-modulated artificial planet-injection based photometry (SMAP) leads to a significant (~3x) gain in photometric accuracy over standard aperture-based photometry and reaches 0.1 mag per point accuracy for our dataset, the signal-to-noise of which is limited by small field rotation. Relative planet-to-planet photometry can be compared be- tween nights, enabling observations spanning multiple nights to probe variability. Recent high-quality relative H-band photometry of the b-c planet pair agree to about 1%.Comment: Astrophysical Journal, in pres
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