ExoClock Project III: 450 new exoplanet ephemerides from ground and space observations

The ExoClock project has been created with the aim of increasing the efficiency of the Ariel mission. It will achieve this by continuously monitoring and updating the ephemerides of Ariel candidates over an extended period, in order to produce a consistent catalogue of reliable and precise ephemerides. This work presents a homogenous catalogue of updated ephemerides for 450 planets, generated by the integration of $\sim$18000 data points from multiple sources. These sources include observations from ground-based telescopes (ExoClock network and ETD), mid-time values from the literature and light-curves from space telescopes (Kepler/K2 and TESS). With all the above, we manage to collect observations for half of the post-discovery years (median), with data that have a median uncertainty less than one minute. In comparison with literature, the ephemerides generated by the project are more precise and less biased. More than 40\% of the initial literature ephemerides had to be updated to reach the goals of the project, as they were either of low precision or drifting. Moreover, the integrated approach of the project enables both the monitoring of the majority of the Ariel candidates (95\%), and also the identification of missing data. The dedicated ExoClock network effectively supports this task by contributing additional observations when a gap in the data is identified. These results highlight the need for continuous monitoring to increase the observing coverage of the candidate planets. Finally, the extended observing coverage of planets allows us to detect trends (TTVs - Transit Timing Variations) for a sample of 19 planets. All products, data, and codes used in this work are open and accessible to the wider scientific community.Comment: Recommended for publication to ApJS (reviewer's comments implemented). Main body: 13 pages, total: 77 pages, 7 figures, 7 tables. Data available at http://doi.org/10.17605/OSF.IO/P298

Pluto's lower atmosphere and pressure evolution from ground-based stellar occultations, 1988-2016

Context. The tenuous nitrogen (N2) atmosphere on Pluto undergoes strong seasonal effects due to high obliquity and orbital eccentricity, and has recently (July 2015) been observed by the New Horizons spacecraft. Aims. The main goals of this study are (i) to construct a well calibrated record of the seasonal evolution of surface pressure on Pluto and (ii) to constrain the structure of the lower atmosphere using a central flash observed in 2015. Methods. Eleven stellar occultations by Pluto observed between 2002 and 2016 are used to retrieve atmospheric profiles (density, pressure, temperature) between altitude levels of ~5 and ~380 km (i.e. pressures from ~ 10 μbar to 10 nbar). Results. (i) Pressure has suffered a monotonic increase from 1988 to 2016, that is compared to a seasonal volatile transport model, from which tight constraints on a combination of albedo and emissivity of N2 ice are derived. (ii) A central flash observed on 2015 June 29 is consistent with New Horizons REX profiles, provided that (a) large diurnal temperature variations (not expected by current models) occur over Sputnik Planitia; and/or (b) hazes with tangential optical depth of ~0.3 are present at 4–7 km altitude levels; and/or (c) the nominal REX density values are overestimated by an implausibly large factor of ~20%; and/or (d) higher terrains block part of the flash in the Charon facing hemisphere

ExoClock Project. III. 450 New Exoplanet Ephemerides from Ground and Space Observations

The ExoClock project has been created to increase the efficiency of the Ariel mission. It will achieve this by continuously monitoring and updating the ephemerides of Ariel candidates, in order to produce a consistent catalog of reliable and precise ephemerides. This work presents a homogenous catalog of updated ephemerides for 450 planets, generated by the integration of ∼18,000 data points from multiple sources. These sources include observations from ground-based telescopes (the ExoClock network and the Exoplanet Transit Database), midtime values from the literature, and light curves from space telescopes (Kepler, K2, and TESS). With all the above, we manage to collect observations for half of the postdiscovery years (median), with data that have a median uncertainty less than 1 minute. In comparison with the literature, the ephemerides generated by the project are more precise and less biased. More than 40% of the initial literature ephemerides had to be updated to reach the goals of the project, as they were either of low precision or drifting. Moreover, the integrated approach of the project enables both the monitoring of the majority of the Ariel candidates (95%), and also the identification of missing data. These results highlight the need for continuous monitoring to increase the observing coverage of the candidate planets. Finally, the extended observing coverage of planets allows us to detect trends (transit-timing variations) for a sample of 19 planets. All the products, data, and codes used in this work are open and accessible to the wider scientific community

Private Health Insurance in France: Between Europeanization and Collectivization

International audienceContext: In France, private health insurance (PHI) has an exceptionally high level of coverage and accounts for 13.7% of health expenditures. A complementary and voluntary scheme, it has been historically dominated by nonprofit, mutual benefit societies. Over the past 20 years, however, the market share of for-profit insurance companies has increased by 47%. Financialization of the field developed, and competition based on new risk management strategies also increased. The broad aim of this paper is to characterize and to elucidate the causes of this trend. More specifically, we are interested in how and to what extent a series of supranational and national policies contributed to this situation.Method: Our data come from three sources. We first reviewed documents published by health insurers, government reports, and newspaper articles. We then conducted two semistructured interview campaigns between September 2017 and May 2018. The first mostly covered private and public actors and their involvement in European Union (EU) policymaking (n=21). The second series of interviews was conducted with another group of actors directly involved at the French level (n = 16).Findings: Our findings support preliminary observations. PHI in France, we argue, is indeed facing a development of competition and market-like instruments. Four major policies (two EU directives and two national reforms) played a significant role in this outcome. Surprisingly, however, it has never been the purpose of legislators and policymakers: while EU directives created a regulatory framework for insurance activities within the Single Market, policies adopted at the national level initially aimed at improving health coverage. We show that it is the interactions and the noncoordination among all of these policies that explain their unexpected outcome.Conclusions: The trend described in this paper is twofold. The first is Europeanization, as PHI in France is increasingly affected by EU legislation. Since this framework tends to favor larger firms and for-profit companies, a reduction in statutory coverage can no longer be considered a quasi-neutral transfer from (publicly owned) social security to nonprofit providers. At the same time, PHI is shifting toward collectivization: as competition increases, complementary health coverage is becoming gradually standardized and based at the corporate level. Together, these changes are likely to reduce freedom of choice and individual welfare, an assumption supported by studies published on the most recent period