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Amandine Gamble, Henri Weimerskirch, Thierry Boulinier. (2020). Seabirds blinded by ticks (Vol. 18). Bachelor's thesis, , .
Abstract: In December 2017, on Possession Island (part of the Crozet Archipelago in the southern Indian Ocean), we observed two breeding white‐chinned petrels (Procellaria aequinoctialis ) with very high levels of tick (Ixodes kerguelenensis ) infestation on both eyes. This degree of infestation was likely responsible for the birds’ death. Although this rare observation may seem anecdotal, it reveals that ticks can be fatal for a long‐lived colonial seabird species, in this case one that is already under pressure from fisheries bycatch and predation by introduced black rats (Rattus rattus ). It also raises questions about the frequency and spatial distribution of such a phenomenon and the conditions that may have been responsible for its occurrence. Such high parasite loads imply high local tick abundances but also a lack of preening by the partner. Could this be linked to the recent death of the partner? Infestations by ticks can affect the health of hosts through blood loss, the injection of toxins, and the transmission of infectious agents. In this instance, the mechanical blocking of eyesight may also have affected the birds’ behavior. The potential impact of climate change on local parasitic infestation levels is another important question. Parasites and diseases can harm endangered species in polar and subpolar areas, and could play critical roles in some circumstances.
Programme: 1151
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Crouzet N., Guillot T., Abe L., Mékarnia D., Agabi K., Bresson Y., Bailet C., Mauclert N., Heras A., Ferruit P., Triaud A., Lagrange A., Schmider ., Giardino G., Isaak K., Kohley R., Michalik D., Foing B., Pilbratt G., Stankov A., Gondoin P., Birkmann S., O'Rourke L. (2020). Two-colour photometry to search for transiting exoplanets with ASTEP at Dome C, Antarctica.
Abstract: Dome C in Antarctica provides exceptional conditions for photometry thanks to the continuous night during the Antarctic winter, a high clear sky fraction, low wind speeds, and a cold and dry atmosphere. The ASTEP project (Antarctic Search for Transiting ExoPlanets) aims at detecting and characterising transiting exoplanets and qualifying this site for photometry in the visible. The main instrument, a 40 cm telescope, has been designed to perform high precision photometry under the extreme conditions of the Antarctic winter and has operated at the Concordia station since 2010. It will be upgraded with two new cameras and a new camera box in order to provide simultaneous two-colour photometry and substantially increase its throughput. The new setup will be operational for the winter campaign 2021 and will allow us to discover transiting exoplanets orbiting bright stars in particular low mass exoplanets, temperate exoplanets, exoplanets around young stars, and to refine the ephemerides of exoplanets discovered by the TESS mission. These observations will provide targets for first characterisation with the CHEOPS mission and atmospheric studies with the JWST and ARIEL missions. In this talk, I will describe the science goals and the upgrade of the ASTEP telescope.
Programme: 1066
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Crouzet N., Mékarnia D., Agabi K., Guillot T., Abe L., Bayliss D., Deeg H., Murgas F., Palle E., Schmider F. (2020). Searching for long period transiting exoplanets with ASTEP South at Dome C, Antarctica. Bachelor's thesis, , .
Abstract: Much of our understanding of gas giant exoplanets come from those transiting in front of bright stars at short orbital separations (P ~ 3 days, a ~ 0.05 au). However, these
Programme: 1066
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Martischang J-P. (2020). Exoplanètes : sélection de calibrateurs et ajustements de transits. Bachelor's thesis, , .
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E. Aristidi, A. Agabi, L. Abe, E. Fossat, A. Ziad, D. Mékarnia. (2020). Dome C coherence time statistics from DIMM data (Vol. 496).
Abstract: We present a reanalysis of several years of DIMM data at the site of Dome C, Antarctica, to provide measurements of the coherence time $\tau0$. Statistics and seasonal behaviour of $\tau0$ are given at two heights above the ground, 3m and 8m, for the wavelength $\lambda=500$nm. We found an annual median value of $2.9$ms at the height of 8m. A few measurements could also be obtained at the height of 20m and give a median value of 6ms during the period June--September. For the first time, we provide measurements of $\tau0$ in daytime during the summer, which appears to show the same time dependence as the seeing with a sharp maximum at 5pm local time. Exceptional values of $\tau0$ above 10ms are met at this particular moment. The continuous slow variations of turbulence conditions during the day offers a natural test bed for a solar adaptive optics system.
Keywords: Astrophysics – Instrumentation and Methods for Astrophysics
Programme: 1066
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Crouzet, N., Guillot T., Abe L., Mékarnia D., Agabi A., Schmider F.-X., Vauglin I. (2020). Astronomie à Concordia : projets et besoins. Bachelor's thesis, , .
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Guillot T. (2020). Discovering Exoplanets from Antarctica with ASTEP. Bachelor's thesis, , .
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Crouzet N., et al. (2020). Towards a two-colour photometer at Dome C, Antartica.
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Crouzet N., et al. (2020). Towards ASTEP+, a two-color photometric telescope at Dome C, Antarctica (Vol. Paper 11447-23). Bachelor's thesis, , .
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Philippe Ricaud, Paolo Grigioni, Romain Roehrig, Pierre Durand, Dana E. Veron. (2020). Trends in Atmospheric Humidity and Temperature above Dome C, Antarctica Evaluated from Observations and Reanalyses (Vol. 11). Bachelor's thesis, , .
Abstract: The time evolution of humidity and temperature above Dome C (Antarctica) has been investigated by considering data from (1) meteorological radiosondes (2005–2017), (2) the microwave radiometer HAMSTRAD (2012–2017), (3) four modern meteorological reanalyses (1980–2017) and (4) the southern annular mode (SAM) index (1980–2017). From these observations (2005–2017), a significant moistening trend (0.08 ± 0.06 kg m−2 dec−1) is associated with a significant warming trend (1.08 ± 0.55 K dec−1) in summer. Conversely, a significant drying trend of −0.04 ± 0.03 kg m−2 dec−1 (−0.05 ± 0.03 kg m−2 dec−1) is associated with a significant cooling trend of −2.4 ± 1.2 K dec−1 (−5.1 ± 2.0 K dec−1) in autumn (winter), with no significant trends in the spring. We demonstrate that 1) the trends identified in the radiosondes (2005–2017) are also present in the reanalyses and 2) the multidecadal variability of integrated water vapor and near-surface temperature (1980–2017) is strongly influenced by variability in the SAM index for all seasons but spring. Our study suggests that the decadal trends observed in humidity and near-surface temperature at Dome C (2005–2017) reflect the multidecadal variability of the atmosphere, and are not indicative of long-term trends that may be related to global climate change.
Keywords: meteorological reanalyses microwave radiometer precipitable water radiosondes SAM index temperature trends
Programme: 910
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