91 research outputs found

    DREAM: III.A helium survey in exoplanets on the edge of the hot Neptune desert with GIANO-B@TNG

    Full text link
    The population of close-in exoplanets features a desert of hot Neptunes whose origin is uncertain. These planets may have lost their atmosphere, eroding into mini-Neptunes and super-Earths. Direct observations of evaporating atmospheres are essential to derive mass-loss estimates and constrain this scenario. The metastable 1083.3nm HeI triplet represents a powerful diagnostic of atmospheric evaporation since it traces the hot gas in extended exoplanet atmospheres, is observable from the ground, and is weakly affected by interstellar medium absorption. We conducted a uniform HeI transmission spectroscopy survey, focusing on 9 planets located at the edges of the Neptunian desert, aiming to gain insights into the role of photo-evaporation in its formation. We observed one transit per planet using the high-resolution, near-infrared spectrograph GIANO-B on the Telescopio Nazionale Galileo. We focused our analysis on the HeI triplet by computing high-resolution transmission spectra. We then employed the p-winds model to interpret the observed transmission spectra. We found no sign of planetary absorption in the HeI triplet in any of the investigated targets. We thus provided 3sigma upper-limit estimations on the thermosphere absorption, temperature, and mass loss, and combined them with past measurements to search for correlations with parameters thought to be drivers in the formation of the HeI triplet. Our results strengthen the importance of performing homogeneous surveys and analyses to bring clarification in the HeI detection and hence in the Neptunian desert origin. Our findings corroborate the literature expectations that the HeI absorption signal correlates with the stellar mass and the received XUV flux. However, these trends seem to disappear in terms of mass-loss rates; further studies are essential to shed light on this aspect and to understand better the photo-evaporation process.Comment: 23 pages, 13 figures, accepted for publication in A&A, after language editin

    Evidence for rangewide panmixia despite multiple barriers to dispersal in a marine mussel

    Get PDF
    Oceanographic features shape the distributional and genetic patterns of marine species by interrupting or promoting connections among populations. Although general patterns commonly arise, distributional ranges and genetic structure are species-specific and do not always comply with the expected trends. By applying a multimarker genetic approach combined with Lagrangian particle simulations (LPS) we tested the hypothesis that oceanographic features along northeastern Atlantic and Mediterranean shores influence dispersal potential and genetic structure of the intertidal mussel Perna perna. Additionally, by performing environmental niche modelling we assessed the potential and realized niche of P. perna along its entire native distributional range and the environmental factors that best explain its realized distribution. Perna perna showed evidence of panmixia across > 4,000 km despite several oceanographic breaking points detected by LPS. This is probably the result of a combination of life history traits, continuous habitat availability and stepping-stone dynamics. Moreover, the niche modelling framework depicted minimum sea surface temperatures (SST) as the major factor shaping P. perna distributional range limits along its native areas. Forthcoming warming SST is expected to further change these limits and allow the species to expand its range polewards though this may be accompanied by retreat from warmer areas.Fundacao para a Ciencia e Tecnologia (FCT-MEC, Portugal) [UID/Multi/04326/2013, IF/01413/2014/CP1217/CT0004]; South African Research Chairs Initiative (SARChI) of the Department of Science and Technology; National Research Foundation; South African National Research Foundation (NRF); Portuguese Fundacao para a Ciencia e Tecnologia (FCT) [SFRH/BPD/85040/2012, SFRH/BPD/111003/2015]info:eu-repo/semantics/publishedVersio

    TRAPPIST Habitable Atmosphere Intercomparison (THAI) workshop report

    Get PDF
    This is the final version. Available on open access from IOP Publishing via the DOI in this recordThe era of atmospheric characterization of terrestrial exoplanets is just around the corner. Modeling prior to observations is crucial in order to predict the observational challenges and to prepare for the data interpretation. This paper presents the report of the TRAPPIST Habitable Atmosphere Intercomparison (THAI) workshop (14-16 September 2020). A review of the climate models and parameterizations of the atmospheric processes on terrestrial exoplanets, model advancements and limitations, as well as direction for future model development was discussed. We hope that this report will be used as a roadmap for future numerical simulations of exoplanet atmospheres and maintaining strong connections to the astronomical community

    D3.2 First performance results for multi -node/multi -antenna transmission technologies

    Full text link
    This deliverable describes the current results of the multi-node/multi-antenna technologies investigated within METIS and analyses the interactions within and outside Work Package 3. Furthermore, it identifies the most promising technologies based on the current state of obtained results. This document provides a brief overview of the results in its first part. The second part, namely the Appendix, further details the results, describes the simulation alignment efforts conducted in the Work Package and the interaction of the Test Cases. The results described here show that the investigations conducted in Work Package 3 are maturing resulting in valuable innovative solutions for future 5G systems.Fantini. R.; Santos, A.; De Carvalho, E.; Rajatheva, N.; Popovski, P.; Baracca, P.; Aziz, D.... (2014). D3.2 First performance results for multi -node/multi -antenna transmission technologies. http://hdl.handle.net/10251/7675

    D 3. 3 Final performance results and consolidated view on the most promising multi -node/multi -antenna transmission technologies

    Full text link
    This document provides the most recent updates on the technical contributions and research challenges focused in WP3. Each Technology Component (TeC) has been evaluated under possible uniform assessment framework of WP3 which is based on the simulation guidelines of WP6. The performance assessment is supported by the simulation results which are in their mature and stable state. An update on the Most Promising Technology Approaches (MPTAs) and their associated TeCs is the main focus of this document. Based on the input of all the TeCs in WP3, a consolidated view of WP3 on the role of multinode/multi-antenna transmission technologies in 5G systems has also been provided. This consolidated view is further supported in this document by the presentation of the impact of MPTAs on METIS scenarios and the addressed METIS goals.Aziz, D.; Baracca, P.; De Carvalho, E.; Fantini, R.; Rajatheva, N.; Popovski, P.; Sørensen, JH.... (2015). D 3. 3 Final performance results and consolidated view on the most promising multi -node/multi -antenna transmission technologies. http://hdl.handle.net/10251/7675

    Genetic transformation of Anthemis nobilis L. (Roman chamomille)

    Full text link
    peer reviewe
    corecore