A hot terrestrial planet orbiting the bright M dwarf L 168-9 unveiled by TESS

We report the detection of a transiting super-Earth-sized planet (R = 1.39 ± 0.09 R⊕ ) in a 1.4-day orbit around L 168-9 (TOI-134), a bright M1V dwarf (V = 11, K = 7.1) located at 25.15 ± 0.02 pc. The host star was observed in the first sector of the Transiting Exoplanet Survey Satellite (TESS) mission. For confirmation and planet mass measurement purposes, this was followed up with ground-based photometry, seeing-limited and high-resolution imaging, and precise radial velocity (PRV) observations using the HARPS and Magellan/PFS spectrographs. By combining the TESS data and PRV observations, we find the mass of L 168-9 b to be 4.60 ± 0.56 M⊕ and thus the bulk density to be 1.74-0.33+0.44 times higher than that of the Earth. The orbital eccentricity is smaller than 0.21 (95% confidence). This planet is a level one candidate for the TESS mission's scientific objective of measuring the masses of 50 small planets, and it is one of the most observationally accessible terrestrial planets for future atmospheric characterization

Development of a IRSN code for dust mobilisation problems in ITER

cited By 7The analysis of accident scenarios in the ITER Fusion facility such as loss of vacuum accidents (LOVA) or ingress of coolant accidents (ICE) is of primary importance in order to evaluate pressure loads generated by a potential dust explosion or mobilisation. Thus the DUST code for simulation of dust mobilisation has been developed in close collaboration between IRSN (France) and the Technical University of Cartagena (Spain), on the basis of the CAST3M code developed at the Commissariat l'Energie Atomique (CEA, France). A high dilute model for the analysis of particle and gas mixtures has been implemented in the code. This type of mixtures is expected in the case of a LOVA inside ITER. The code will permit the analysis of dust spatial distribution, remobilisation and entrainment, and explosion. Special attention is paid to the study of the closure relationships which characterise the physical phenomena involved in this sort of problems and a model based on the force balance has been implemented as well. The implementation of the adhesion/re-suspension model is carefully described. To test the code qualitatively, two benchmarks have been studied taking into account the influence of different parameters. Some conclusions are finally drawn. © 2010 Published by Elsevier B.V. All rights reserved

Its all about connections: hubs and invasion in habitat networks

International audienceDuring the early stages of invasion, the interaction between the features of the invaded landscape, notably its spatial structure, and the internal dynamics of an introduced population has a crucial impact on establishment and spread. By approximating introduction areas as networks of patches linked by dispersal, we characterised their spatial structure with specific metrics and tested their impact on two essential steps of the invasion process: establishment and spread. By combining simulations with experimental introductions of Trichogramma chilonis (Hymenoptera: Trichogrammatidae) in artificial laboratory microcosms, we demonstrated that spread was hindered by clusters and accelerated by hubs but was also affected by small-population mechanisms prevalent for invasions, such as Allee effects. Establishment was also affected by demographic mechanisms, in interaction with network metrics. These results highlight the importance of considering the demography of invaders as well as the structure of the invaded area to predict the outcome of invasions