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Within our program of physical characterization of trans-Neptunian objects and centaurs, we predicted a stellar occultation by the centaur (54598) Bienor to occur on January 11, 2019, with good observability potential. We obtained high accuracy astrometric data to refine the prediction, resulting in a shadow path favorable for the Iberian Peninsula. This encouraged us to carry out an occultation observation campaign that resulted in five positive detections from four observing sites. This is the fourth centaur for which a multichord (more than two chords) stellar occultation has been observed so far, the other three being (2060) Chiron, (10199) Chariklo, and (95626) 2002 GZ32. From the analysis of the occultation chords, combined with the rotational light curve obtained shortly after the occultation, we determined that Bienor has an area-equivalent diameter of 150 ± 20 km. This diameter is ∼30 km smaller than the one obtained from thermal measurements. The position angle of the short axis of the best fitting ellipse obtained through the analysis of the stellar occultation does not match that of the spin axis derived from long-term photometric models. We also detected a strong irregularity in one of the minima of the rotational light curve that is present no matter the aspect angle at which the observations were done. We present different scenarios to reconcile the results from the different techniques. We did not detect secondary drops related to potential rings or satellites. Nonetheless, similar rings in size to that of Chariklo’s cannot be discarded due to low data accuracy., European Research Council (ERC) 669416, Space Research Initiative from State of Florida, Spanish grant (MCIU/AEI/FEDER, UE) AYA-2017-84637-R, National Research, Development & Innovation Office (NRDIO) - Hungary K-138962 CAPES-PRINT/UNESP 88887.310463/2018-00 88887.571156/2020-00, Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPQ) 427700/2018-3 310683/2017-3 473002/2013-2 314772/2020-0 308150/2016-3 305917/2019-6 150612/2020-6, Fundacao Carlos Chagas Filho de Amparo a Pesquisa do Estado do Rio De Janeiro (FAPERJ) E-26/111.488/2013, Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP) 2018/11239-8, Spanish Government PGC2018-097374-B-I00, Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES) 001, Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPQ), Fundacao de Apoio a Pesquisa do Distrito Federal (FAPDF) 465376/2014-2, Spanish Government AYA-2017-84637-R SEV-2017-0709, Junta de Andalucia PY20_01309, Agencia Estatal de Investigacion PID2020-112789GB-I00, Fondos de Inversiones de Teruel (FITE)

M. Pajola et al., On 2022 September 26, the DART spacecraft will impact the surface of Dimorphos, the ∼160 m size satellite of the binary near-Earth asteroid (NEA) (65803) Didymos. What will be observed on the surfaces of both asteroids and at the DART impact site is largely unknown, beyond the details of Didymos revealed by previous Arecibo and Goldstone radar observations. We present here the expected DART and LICIACube observations of the Didymos system and discuss the planned mapping strategies. By searching similar geological features and processes identified on other NEAs, we constrain the impact conditions that DART might encounter at Dimorphos, assessing both the asteroid's surface and interior structure., This work was supported by the Italian Space Agency (ASI) within the LICIACube project (ASI-INAF agreement AC n. 2019-31-HH.0). This work was supported by the DART mission, NASA Contract No. 80MSFC20D0004. E.A. is funded by the University of Arizona. S.S. acknowledges support from NASA as part of the Double Asteroid Redirection Test (DART) Participating Scientist Program. J.M.T.-R. is funded by the research project (PGC2018-097374-B-I00), funded by FEDER/Ministerio de Ciencia e Innovación—Agencia Estatal de Investigación. P.M. acknowledges ESA as well as funding from the French space agency CNES, from the European Union's Horizon 2020 research and innovation program under grant agreement No. 870377 (project NEO-MAPP) and from the CNRS through the MITI interdisciplinary programs.

“The Early Evolution of the Atmospheres of Terrestrial Planets” presents the main processes participating in the atmospheric evolution of terrestrial planets. A group of experts in the different fields provide an update of our current knowledge on this topic. Several papers in this book discuss the key role of nitrogen in the atmospheric evolution of terrestrial planets. The earliest setting and evolution of planetary atmospheres of terrestrial planets is directly associated with accretion, chemical differentiation, outgassing, stochastic impacts, and extremely high energy fluxes from their host stars. This book provides an overview of the present knowledge of the initial atmospheric composition of the terrestrial planets. Additionally it includes some papers about the current exoplanet discoveries and provides additional clues to our understanding of Earth’s transition from a hot accretionary phase into a habitable world. All papers included were reviewed by experts in their respective fields. We are living in an epoch of important exoplanet discoveries, but current properties of these exoplanets do not match our scientific predictions using standard terrestrial planet models. This book deals with the main physio-chemical signatures and processes that could be useful to better understand the formation of rocky planets.