Exoclimes_Conference_booklet1

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models can still be applied in this context to hot Neptunes and super-Earths to place constraints on atmospheric properties using the most recent transit spectroscopy results. New insights on beta Pictoris: discovery of two different populations Flavien Kiefer — Institut d'Astrophysique de Paris! High-resolution spectroscopic observations of beta Pictoris made with HARPS bring new information on the exocomets falling onto the star (FEB scenario). With more than a thousand spectra gathered between 2003 and 2011, we have around 6000 variable absorptions detected. Using this huge catalogue of events we achieved an unprecedented statistical and temporal study of beta Pic comets. We will present the results of this statistial analysis, and display the evidence that allowed us to discover two very different populations of comets in this young planetary system. Magnetic fields on L-type brown dwarfs! Oleksii Kuzmychov — Kiepenheuer-Institut für Sonnenphysik Several rapidly-rotating L-type dwarfs exhibit transient but periodic radio pulses that are possibly driven by electron-cyclotron maser (e.g., Hallinan et al. 2007, 2008). For this mechanism to work, a few kG magnetic field is required. In order to examine whether these objects possess such a strong magnetic field, we model polarized spectra of L-type brown dwarfs including transitions in diatomic molecules, such as CrH, FeH, and TiO. We compare these synthetic spectra with full Stokes spectra of two brown dwarfs measured at several rotational phases using the low-resolution spectropolarimeter LRIS at the Keck Observatory in August 2012. We are able to constrain the magnetic field strength in these objects and discuss implications of our results. Spectral Retrieval Analysis of the Directly Imaged exoplanets around HR 8799 Jae-Min Lee — University of Zurich The direct-imaged exoplanets around HR 8799 are photometrically distinct from their parent star. Spectroscopic measurements along with photometric points between 1 and 5 µm provide vital information on the thermal and chemical structure of the atmosphere, which have never been achieved from transiting exoplanets. However, it is still mysterious that the characteristics of the atmosphere show a mixture of brown dwarf and gas giant features, calling its radius, surface gravity and mass into a question. Here, we perform inverse modelling by exploiting an optimal estimation retrieval technique and sweep the parametrized radius and surface gravity space with phenomenological cloud scenarios. Unlike previous approaches, in which the cloud models are rather sophisticated, we minimise the number of cloud parameters, e.g., mono-disperse cloud particle size and optical depth of cloud. We find that the identity of the cloud material gives a non-detectable effect to our results because the refractive indices of most of materials plausible in this class of atmosphere are not distinguishable at these wavelengths. Also, we report physical properties of these planets, such as radius, surface gravity and mass, which can provide useful constraints for building its formation scenario. 60
A Comparison of Exoplanet Atmospheric Retrieval Techniques Michael Line!— University of California Santa Cruz Secondary eclipse spectra allow us to infer the temperatures and compositions of exoplanet atmospheres. A variety of statistical approaches exist to determine the most probable set of temperatures and compositions such as Markov Chain Monte Carlo and Optimal Estimation. I will give an overview of these approaches in the context of the Bayesian formalism and discuss the similarities and differences in their derived posterior probabilities. I will show in which regimes optimal estimation is appropriate and in which regimes MCMC approaches are necessary. Finally, as a side, I will discuss the potential pitfalls of statistical determinations of the atmospheric C/O ratio. Young and Planetary-Mass: Connecting Low-Gravity Field Brown Dwarfs and Directly Imaged Gas-Giant Planets! Michael Liu — University of Hawaii, Institute for Astronomy! Direct detections of young gas-giant exoplanets and recent identification of very young field brown dwarfs are strengthening the observational link between the exoplanet and brown dwarf populations, enriching our understanding of both classes of objects. However, studies to date have typically focused on individual discoveries. We present a large comprehensive study of the youngest field brown dwarfs, comprising both previously known objects and our new discoveries from the Pan-STARRS-1 wide-field survey. These objects have physical properties that overlap young gas-giant planets and thus are promising analogs for studying exoplanet atmospheres at high S/N and spectral resolution down to ~5 Jupiter masses. We combine high-quality spectra and parallaxes to study their spectral energy distributions, luminosities, temperatures and ages. We demonstrate that the peculiar IR colors and magnitudes of the planets around 2MASS J1207-39 and HR 8799 do occur in some young brown dwarfs, but these properties do not have a simple correspondance with age. We find that young field brown dwarfs can have unusally low temperatures (but they are not underluminous, as often claimed). To help provide a reference for upcoming extreme-contrast imaging surveys, we establish a grid of spectral standards and benchmarks, based on membership in nearby young moving groups, in order to calibrate gravity (age) and temperature diagnostics in near-IR spectroscopy. Finally, we use our data to critically examine the possibility that free-floating objects and companions may share different evolutionary histories, thereby complicating the "brown dwarf-exoplanet connection”. MagAO/VisAO Optical Imaging of beta Pictoris b: A Comparative Study of Exoplanets and Brown Dwarfs! Jared! Males — University of Arizona We used the Magellan AO system's visible wavelength diffraction limited camera, VisAO, to image the ~10 Jupiter mass exoplanet beta Pictoris b. This is the first ground-based direct image of an exoplanet at wavelengths less than 1 micron. Using our photometry, combined with existing JHK measurements, we compare beta Pic b to field brown dwarf spectra. Our analysis yields a rigorous empirical determination of the planet's spectral type, and through this an estimate of effective temperature. Our photometry highlights the extreme diversity amongst the directly imaged extrasolar giant planets and both field and companion brown dwarfs, yet points to remarkable similarities in formation and evolution despite this diversity. 61
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PROGRAMME & ABSTRACTS 1
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Presentation Venue Davos is a winte
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Programme Tuesday 11th Session: Exo
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Programme Thursday 13th Session: Br
Page 10 and 11: Participants PARTICIPANTS Dorian! A
Page 12 and 13: Participants Sara! Khalafinejad! Ha
Page 14 and 15: TALKS/POSTERS ABSTRACTS * INSIGHTS
Page 16 and 17: Finally, we will show GCM simulatio
Page 18 and 19: Our results show that whatever the
Page 20 and 21: planets are now available, constrai
Page 22 and 23: sophisticated atmosphere and surfac
Page 24 and 25: Exoplanetary Extreme Space Weather
Page 26 and 27: consistently calculates the ground
Page 28 and 29: pressure.The Bcool project is an in
Page 30 and 31: the climate on exoplanets by provid
Page 32 and 33: new inversion framework for the int
Page 34 and 35: combined observations provide const
Page 36 and 37: Constraining the degeneracy of Supe
Page 38 and 39: structure by integrating the couple
Page 40 and 41: carbon- and oxygen-bearing species.
Page 42 and 43: abundances of molecules in the atmo
Page 44 and 45: data reduction stage crucial to our
Page 46 and 47: us to reproduce this transit asymme
Page 48 and 49: atios, and temperature profiles, th
Page 50 and 51: triple stellar system, and a revise
Page 52 and 53: OH, H2, CO, CO2, CH4, NH3, MgO, MgS
Page 54 and 55: non hydrostatic Euler equations on
Page 56 and 57: ongoing. This will help us understa
Page 58 and 59: measurements of Planet Beta Pictori
Page 62 and 63: Comprehensive Results from the Weat
Page 64: p m~êëÉåå M RMM=ã pql`hb kpq
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