Exploring and Validating Exoplanet Atmospheric Retrievals with Solar System Analog Observations

Solar System observations that serve as analogs for exoplanet remote sensing data can provide important opportunities to validate ideas and models related to exoplanet environments. Critically, and unlike true exoplanet observations, Solar System analog data benefit from available high-quality ground- or orbiter-derived "truth" constraints that enable strong validations of exoplanet data interpretation tools. In this work, we first present a versatile atmospheric retrieval suite, capable of application to reflected light, thermal emission, and transmission observations. The tool -- dubbed rfast -- is designed, in part, to enable exoplanet mission concept feasibility studies. Following model validation, the retrieval tool is applied to a range of Solar System analog observations for exoplanet environments. Retrieval studies using Earth reflected light observations from NASA's EPOXI mission provide a key proof-of-concept for under-development exo-Earth direct imaging concept missions. Inverse modeling applied to an infrared spectrum of Earth from the Mars Global Surveyor Thermal Emission Spectrometer achieves good constraints on atmospheric gases, including many biosignature gases. Finally, retrieval analysis applied to a transit spectrum of Titan derived from the Cassini Visual and Infrared Mapping Spectrometer provides a proof-of-concept for interpreting more feature-rich transiting exoplanet observations from NASA's James Webb Space Telescope (JWST). In the future, Solar System analog observations for exoplanets could be used to verify exoplanet models and parameterizations, and future exoplanet analog observations of any Solar System worlds from planetary science missions should be encouraged.Comment: submitted to PSJ; community comments and feedback welcome

L'abri sous roche Cadet 3 (Marie-Galante) : un gisement à accumulations de faune et à vestiges archéologiques

International audienceA 2 m² recognition test pit was undertaken in 2004 in this small rock shelter, immediately nearby Grotte Cadet 2. The excavation revealed a 1,20 m thick sedimentary infilling. The sediments blocked behind an accumulation of blocks at the cave entrance accumulated since the late Pleistocene and during the Holocene. The lower part of the infilling is composed of phosphate deposits rich in vertebrate faunal remains, land snails and land crabs. The basis of this level was dated to about 13 800 BC. The upper part of the sequence yielded traces of a late Neoindian occupation dated to about AD 1000 and of subsequent historical remains. About fifty taxa were identified. The stratigraphic sequence therefore reveals the history of the animal peopling and subsequent anthropization of the Guadeloupean environments. The deepest layers have yielded a high diversity of Chiroptera, avian, saurian and amphibian fauna. The part of native vertebrate species decreases progressively: this fact probably reflects an direct (introduction, predation) or indirect (ecosystem disturbance) anthropization of the environments. On the other hand, the part of land snails and land crabs grows substantially. Finally, the upper levels, related to post-Columbian deposits, illustrate a rather sudden stop in the cavity's use by the small native insular fauna and a dramatic drop in vertebrates' diversity. The old world domestic taxa then compose most of the taphocenose of the shelter. The faunal associations enable to partially infer the composition of the surrounding environments during each period. However this reading is made complex given the multiplicity of agents responsible in these accumulations, a point which is discussed in this paper. Finally this assemblage offers a remarquable stratified series, quite new for the Lesser Antilles islands.Ce petit abri sous-roche, immédiatement voisin de la Grotte Cadet 2, a fait l'objet d'un sondage de reconnaissance de 2 m2. L'investigation a révélé un remplissage d'une épaisseur de 1,20 m. Les sédiments piégés en arrière de blocs effondrés à l'entrée de la cavité se sont accumulés depuis la fin du Pléistocène et au cours de l'Holocène. La partie inférieure du remplissage est constituée de dépôts phosphatés riches en restes de faune vertébrée, de crustacés et de gastéropodes terrestres. La base a été datée autour de 13 800 av. J.-C. La partie supérieure de la série a livré les traces d'une occupation du Néoindien récent datée autour de l'an 1000, puis de vestiges d'époque historique. Près d'une cinquantaine de taxons ont été identifiés. La séquence stratigraphique révèle l'histoire du peuplement animal et, en conséquence, de l'anthropisation des milieux. Les couches profondes ont fourni une grande diversité de chiroptères, d'oiseaux, de squamates et d'amphibiens. La part des espèces natives de vertébrés diminue au fur et à mesure de l'édification des dépôts, ce qui est probablement dû à une anthropisation des milieux, directe (introduction, prédation) ou indirecte (perturbations des ecosystèmes), alors que les crustacés et les gastéropodes terrestres prennent une part de plus en plus conséquente. Enfin, les couches superficielles, correspondant à des niveaux post-colombiens, se caractérisent par une disparition brutale de l'utilisation de la cavité par les petites faunes natives de l'île et une chute drastique de la biodiversité des vertébrés. Les animaux domestiques constituent alors l'essentiel de la taphocénose de l'abri. Les associations fauniques permettent d'inférer en partie la composition des milieux écologiques environnants au cours de chaque période. Cependant la multiplicité des agents accumulateurs potentiels complique cette lecture et est discutée dans cet article. Enfin, cet assemblage permet de proposer une série faunique stratifiée remarquable pour les Petites Antilles

Bioverse: The Habitable Zone Inner Edge Discontinuity as an Imprint of Runaway Greenhouse Climates on Exoplanet Demographics

Long-term magma ocean phases on rocky exoplanets orbiting closer to their star than the runaway greenhouse threshold - the inner edge of the classical habitable zone - may offer insights into the physical and chemical processes that distinguish potentially habitable worlds from others. Thermal stratification of runaway planets is expected to significantly inflate their atmospheres, potentially providing observational access to the runaway greenhouse transition in the form of a "habitable zone inner edge discontinuity" in radius-density space. Here, we use Bioverse, a statistical framework combining contextual information from the overall planet population with a survey simulator, to assess the ability of ground- and space-based telescopes to test this hypothesis. We find that the demographic imprint of the runaway greenhouse transition is likely detectable with high-precision transit photometry for sample sizes $\gtrsim 100$ planets if at least ~10 % of those orbiting closer than the habitable zone inner edge harbor runaway climates. Our survey simulations suggest that in the near future, ESA's PLATO mission will be the most promising survey to probe the habitable zone inner edge discontinuity. We determine survey strategies that maximize the diagnostic power of the obtained data and identify as key mission design drivers: 1. A follow-up campaign of planetary mass measurements and 2. The fraction of low-mass stars in the target sample. Observational constraints on the runaway greenhouse transition will provide crucial insights into the distribution of atmospheric volatiles among rocky exoplanets, which may help to identify the nearest potentially habitable worlds.Comment: Accepted for publication in The Planetary Science Journal. For a video abstract, see https://youtu.be/acgKcdTTv9c. 29 pages, 12 figures, 1 table. All source code is available at https://github.com/matiscke/hz-inner-edge-discontinuit

L'abri sous roche Cadet 3 (Marie-Galante) : un gisement à accumulations de faune et à vestiges archéologiques

International audienceThis small rock shelter, immediately nearby Grotte Cadet 2, was the subject in 2004 of a 2 m² recognition test pit. The excavation revealed a 1,20 m thick sedimentary infilling. Sediments were trapped there after the cavity’s entrance was blocked by an accumulation of blocks at the top of the slope deposits’ prism. The colluviums thus accumulated since the late Pleistocene and during the Holocene. The stratigraphy is composed, in its lower portion, of phosphate deposits rich in vertebrate faunal remains, land snails and land crabs. The basis of this level has been dated to about 13 800 BC. The upper part of the sequence delivered traces of a late Neoindian occupation dated to about AD 980 and of subsequent historical remains. Through its multidisciplinary study, this cavity deposit with thanatocenoses yields a new frame of reference for Guadeloupe.Altogether, the levels yielded close to fifty taxa of which some are no longer present in the Guadeloupean archipelago. The stratigraphic sequence therefore reveals the history of the peopling and subsequent anthropisation of the Guadeloupean environments. Indeed, the deepest layers have yielded a high diversity of small mammalian (exclusively Chiroptera), avian, saurian and amphibian fauna. It was replaced during pre-Columbian times by larger species (i.e. rice rat, agouti, and iguana) while the native vertebrate species decreased, likely in relation to the environment's anthropisation, and crabs and land snails increased. Finally, the upper levels, related to post-Columbian deposits, illustrate a rather sudden stop in the cavity’s use by the small native insular fauna and a dramatic drop in vertebrate's diversity. The old world domestic taxa (pig, caprines, and rat) then compose most of the taphocenose of the shelter.Este pequeño refugio bajo roca, vecino de la Cueva Cadet 2, fue objeto de un sondeo de reconocimiento de 2 m2. La investigación reveló un relleno sedimentario de 1m20 de espesor. Los sedimentos, retenidos detrás de unos bloques desprendidos en la entrada de la cavidad, se han acumulado durante el Pleistoceno final y el Holoceno. La parte inferior del relleno está constituida por depósitos fosfatados ricos en restos de fauna vertebrada, de crustáceos y de gasterópodos terrestres. La base de este ha sido datada alrededor de 13 800 a.C. En la parte superior de la serie se encontraron trazas de una ocupación Neoindia reciente datada alrededor del año 1000 y seguida con restos de época histórica . Cerca de cincuenta taxones hana sido identificados. La secuencia estratigráfica revela la historia de la población animal y de la antropisación del paisaje. Las capas profundas han proporcionado una gran diversidad de quirópteros, aves, escamosos y anfibios. La parte correspondiente a las especies nativas disminuye durante la formación del depósito, probablemente debido a la antropización directa (introducción, predación) o indirecta (perturbación de los ecosistemas) del medio ambiente, mientras que los gasterópodos terrestres representan una parte cada vez más consecuente. Por último, el conjunto de capas superficiales correspondientes a los niveles post-colombinos se caracteriza por la desaparición brusca de la utilización de la cueva por las pequeñas faunas nativas de la isla y por la drástica disminución de la biodiversidad de vertebrados. Por el contrario, los animales domésticos constituyen ahora la parte fundamental de la tafocenosis. Las asociaciones faunísticas permiten inferir la composición parcial de los nichos ecológicos circundantes durante cada uno de los periodos representados. Del mismo modo, la pluralidad de los agentes de acumulación potenciales es igualmente discutida. Finalmente, este conjunto permite proponer una serie faunística estratificada remarcable para las Antillas Menores.Ce petit abri sous-roche, immédiatement voisin de la Grotte Cadet 2, a fait l’objet en 2004 d’un sondage de reconnaissance de 2 m2. L’investigation a révélé un remplissage sédimentaire d’une épaisseur de 1,20 m. Les sédiments sont piégés dans le site après qu’une série de blocs accumulés au sommet du prisme de dépôts de pente ait barré l’entrée de la cavité. Les colluvions se sont ainsi accumulées depuis la fin du Pléistocène et au cours de l’Holocène. La stratigraphie est constituée, dans sa partie inférieure, par des dépôts phosphatés riches en restes de faune vertébrée, de gastéropodes pulmonés et de crustacés terrestres. La base de ce niveau a été datée autour de 13 800 av. J.-C. La partie supérieure de la série a livré les traces d’une occupation du Néoindien récent datée autour de 980 ap. J.-C. puis des vestiges d’époque historique. Ce gisement à thanatocénoses en cavité constitue, grâce à son étude pluri-disciplinaire, un premier référentiel en Guadeloupe.L’ensemble des niveaux a livré près d’une cinquantaine de taxons dont certains sont absents aujourd’hui de l’archipel guadeloupéen. La séquence stratigraphique révèle donc l’Histoire de ce peuplement et de l’anthropisation des milieux. En effet, les couches profondes ont fourni une grande diversité de petite faune mammalienne (uniquement Chiroptères), aviaire, sauriennne et amphibienne. Cette faune a été remplacée au cours des temps précolombiens par des espèces de plus grande taille (rats des rizières, agoutis et iguanes, par exemple) et les espèces natives de Vertébrés vont diminuer, ce qui est probablement dû à une anthropisation des milieux, alors que les Crustacés et les Gastéropodes prendront une part de plus en plus conséquente. Enfin, les couches superficielles, correspondant à des niveaux post-colombiens illustrent une disparition presque brutale de l’utilisation de la cavité par les petites faunes natives de l’île et une chute drastique de la biodiversité des Vertébrés. En revanche, les taxons domestiques (cochons, caprinés et rats de l’ancien monde) ont alors constitué l’essentiel de la taphocénose de l’abri

Géoarchéologie fluviale

Géoarchéologie fluvial

Combined collision-induced dissociation and photo-selected reaction monitoring mass spectrometry modes for simultaneous analysis of coagulation factors and estrogens

AbstractOral estrogens are directly associated with changes in plasma levels of coagulation proteins. Thus, the detection of any variation in protein concentrations due to estrogen contraceptives, by a simultaneous analysis of both coagulation proteins and estrogens, would be a very informative tool. In the present study, the merit of photo-selected reaction monitoring (SRM), a new analytical tool, was evaluated towards estrogens detection in plasma. Then, SRM and photo-SRM detection modes were combined for the simultaneous analysis of estrogen molecules together with heparin co-factor and factor XIIa, two proteins involved in the coagulation cascade. This study shows that photo-SRM could open new multiplexed analytical routes

Dynamic centriolar localization of Polo and Centrobin in early mitosis primes centrosome asymmetry

Centrosomes, the main microtubule organizing centers (MTOCs) of metazoan cells, contain an older "mother" and a younger "daughter" centriole. Stem cells either inherit the mother or daughter-centriole-containing centrosome, providing a possible mechanism for biased delivery of cell fate determinants. However, the mechanisms regulating centrosome asymmetry and biased centrosome segregation are unclear. Using 3D-structured illumination microscopy (3D-SIM) and live-cell imaging, we show in fly neural stem cells (neuroblasts) that the mitotic kinase Polo and its centriolar protein substrate Centrobin (Cnb) accumulate on the daughter centriole during mitosis, thereby generating molecularly distinct mother and daughter centrioles before interphase. Cnb's asymmetric localization, potentially involving a direct relocalization mechanism, is regulated by Polo-mediated phosphorylation, whereas Polo's daughter centriole enrichment requires both Wdr62 and Cnb. Based on optogenetic protein mislocalization experiments, we propose that the establishment of centriole asymmetry in mitosis primes biased interphase MTOC activity, necessary for correct spindle orientation

Mass and pressure constraints on galaxy clusters from interferometric SZ observations

Following on our previous study of an analytic parametric model to describe the baryonic and dark matter distributions in clusters of galaxies with spherical symmetry, we perform an SZ analysis of a set of simulated clusters and present their mass and pressure profiles. The simulated clusters span a wide range in mass, 2.0 x 10^14 Msun < M200 < 1.0 x 10^15Msun, and observations with the Arcminute Microkelvin Imager (AMI) are simulated through their Sunyaev- Zel'dovich (SZ) effect. We assume that the dark matter density follows a Navarro, Frenk and White (NFW) profile and that the gas pressure is described by a generalised NFW (GNFW) profile. By numerically exploring the probability distributions of the cluster parameters given simulated interferometric SZ data in the context of Bayesian methods, we investigate the capability of this model and analysis technique to return the simulated clusters input quantities. We show that considering the mass and redshift dependency of the cluster halo concentration parameter is crucial in obtaining an unbiased cluster mass estimate and hence deriving the radial profiles of the enclosed total mass and the gas pressure out to r200.Comment: 5 pages, 2 tables, 3 figure