Program schedule

Week 1

See the Conference program page

 

During Weeks 2-5, the program will host 1 or sometimes 2 talks per day. The list of talks will be updated shortly. All the talks will be held in ISB 102. 

Week 2 

Monday:

  • 10:00-10:30: Coffee
  • 2:00-3:30: Fellows project proposals

Tuesday

  • 10:00-10:30: Coffee
  • 10:30-11:30: Fred C. Adams, University of Michigan

"Magnetically Controlled Flows in Planetary Outflows"

We consider magnetic field effects on outflows from exoplanets, which have now been observed. For typical
parameters, the magnetic field pressure dominates the ram pressure of
the outflow by many orders of magnitude. Magnetically controlled
outflows differ significantly from previous spherical models: The
outflow rates are somewhat smaller, and the flow is launched primarily
from the polar regions of the planet.  

[1] Magnetically Controlled Outflows from Hot Jupiters. 
Adams, F. C. 2011, ApJ, 730, 27 

Wednesday

  • 10:00-10:30: Coffee
  • 10:30-11:30: Eliza Kempton, Grinnell College

"Cloud Composition in Super-Earth Atmospheres"

Attempts to determine the composition of super-Earth atmospheres have so far been plagued by the presence of clouds. Yet the theoretical framework to understand these clouds is still in its infancy. For the super-Earth archetype GJ 1214b, KCl, Na2S, and ZnS have been proposed as condensates that would form under the condition of chemical equilibrium, if the planet’s atmosphere has a bulk composition near solar. Condensation chemistry calculations have not been presented for a wider range of atmospheric bulk composition that is to be expected for super-Earth exoplanets. I will present a theoretical context for the formation of super-Earth clouds in atmospheres of varied composition by determining which condensates are likely to form, under the assumption of chemical equilibrium. We model super-Earth atmospheres assuming they are formed by degassing of volatiles from a solid planetary core of chondritic material. Given the atomic makeup of these atmospheres, we minimize the global Gibbs free energy of over 550 gases and condensates to obtain the molecular composition of the atmospheres over a temperature range of 350-3,000 K. Clouds should form along the temperature-pressure boundaries where the condensed species appear in our calculations. The super-Earth atmospheres that we study range from highly reducing to oxidizing and have carbon to oxygen (C:O) ratios that are both sub-solar and super-solar, thereby spanning a diverse range of atmospheric composition that is appropriate for low-mass exoplanets. Some condensates appear across all of our models. However, the majority of condensed species appear only over specific ranges of H:O and C:O ratios. I will present the results of our cloud composition calculations for GJ 1214b, and I will discuss the implications for understanding the composition of clouds in a diverse population of low-mass exoplanets.   

Thursday

  • 10:00-10:30: Coffee
  • 10:30-11:30: Dorian Abbot, University of Chicago

"Analytical investigation of the decrease in the size of the habitable zone due to limited CO2 outgassing rate and the resulting climate limit cycles" The habitable zone concept is important because it focuses the scientific search for extraterrestrial life and aids the planning of future telescopes. Recent work has shown that planets near the outer edge of the habitable zone might not actually be able to stay warm and habitable if CO2 outgassing rates are not large enough to maintain high CO2 partial pressures against removal by silicate weathering. In this paper I use simple equations for the climate and CO2 budget of a planet in the habitable zone that can capture the qualitative behavior of the system. With these equations I derive an analytical formula for an effective outer edge of the habitable zone, including limitations imposed by the CO2 outgassing rate. I then show that climate cycles between a Snowball state and a warm cli- mate are only possible beyond this limit if the weathering rate in the Snowball climate is smaller than the CO2 outgassing rate (otherwise stable Snowball states result). I derive an analytical solution for the climate cycles including a formula for their period in this limit. This work allows us to explore the qualitative effects of weathering processes on the effective outer edge of the habitable zone, which is important because weathering parameterizations are uncertain.

Friday

  • 10:00-10:30: Coffee
  • 10:30-11:30: Theodora Karalidi, Steward Observatory, University of Arizona

"Mapping the cloudy skies of brown dwarfs and other ultracool atmospheres with Aeolus"

Clouds play crucial and diverse roles in planetary climates. Observations of clouds on Earth, and other planets of our Solar system, have shown that the effects of clouds on the planetary climate depend on both the micro and macro-physical properties of the clouds, Characterizing the cloud coverage of a planet is thus crucial for assessing the planet’s habitability. Observations of exoplanets and brown dwarfs indicate that their atmospheres are dominated by clouds. However, no telescope is able to resolve the disk of these objects and provide us with spatial information on their cloud coverage. A way to study the structure and evolution of clouds in these atmospheres is to create maps via forward modeling of the observed spectra and phase curves. In this talk I will present how we map the cloud structure of brown dwarf atmospheres using Aeolus, a MCMC code that maps the top-of-the-atmosphere structure of an atmosphere using observational light curves. I will also discuss how we study the evolution of these maps over time to get an insight in the dynamics that govern brown dwarf atmospheres, and how we can apply Aeolus to map the variable cloud structures of imaged giant exoplanets currently, and terrestrial exoplanets in the future.

  •  Lunchtime career development workshop "The impostor Syndrome", Sarah Rugheimer

Week 3 

Monday: July 4th, no seminar

Tuesday

  • 10:00-10:30: Coffee
  • 10:30-11:30: Kaitlin Kratter, University of Arizona

"Planets in binary star systems"

Kepler has changed our view of planet formation in binaries by providing extraordinary examples of both circumbinary planetary systems and planets orbiting one member of a binary. In addition to revealing that planet formation can proceed in extreme environments, we can also use these seeming odd-balls to better understand planet formation around normal stars. I will describe how both types of systems provide unique and complementary constraints on the process of planet formation using Kepler 444 and Kepler 47 as case studies.

Wednesday

  • 10:00-10:30: Coffee
  • 10:30-11:30: Colin Goldblatt, University of Victoria

"Nuclear Winter: A Review and Reminder" This is a seminar that I'm giving because I think it is important. "Nuclear winter" is a prediction that arose directly from the planetary sciences (specifically NASA Ames, just over the hill) in the 80s and has profound public policy implications, but gets easily or conveniently forgotten about (and rarely taught). I'll review the physics, and recent work on this problem. Briefly: the dust load that nuclear war would put into the atmosphere would be sufficient to cause global cooling sufficient to cause devastating worldwide crop failures. Fatalities from starvation would out-weigh those from direct conflict. A superpower war would be cataclysmic, while recent work showing that a regional conflict (e.g. India-Pakistan), or missiles from a single Trident submarine, would be sufficient to cause a mild nuclear winter. In an astrobiology context, this is something to think about in the 'duration of technological civilization' term in the Drake equation, as we struggle through our technological adolescence.

Thursday

  • 10:00-10:30: Coffee
  • 10:30-11:30: Eric Lopez, University of Edinburgh

"Re-inflated Warm Jupiters around Red Giants: A New Test for Models of Hot Jupiter Inflation"

Ever since the discovery of the first transiting hot Jupiter, models have sought to explain the anomalously large radii of highly irradiated gas giants. We now know that the size of the hot Jupiter radius anomaly scales strongly with a planet's level of irradiation and numerous models have since been developed to help explain these inflated radii. In general however, these models can be grouped into two broad categories: 1) models that directly inflate planetary radii by depositing a fraction of the incident irradiation in the convective interior and 2) models that simply slow a planet's radiative cooling allowing it to retain more heat from formation and thereby delay contraction. I will propose a new test to distinguish between these two classes of models, by examining the post-main sequence radius evolution of gas giants with moderate orbital periods of ~10-30 days. If hot Jupiter inflation actively deposits heat in a planets interior then current and upcoming transit surveys should uncover a new population of "re-inflated" gas giants around post main sequence stars. 

Friday

  • 10:00-10:30: Coffee
  • 10:30-11:30: James Owen, Institute for Advanced Study

"Sculpting Exoplanets by Evaporation"

I will discuss how evaporation of a H/He envelope from a low-mass planet can dramatically alter it's evolution, and its properties at an age of a few Gyr (close to when it will be observed today). Planet evaporation produces several tell-tale indicators in the exoplanet population, such as a lack of close-in, large radius sub-neptunes and an ``Evaporation-valley". I will also show that evaporation can be used to break some of the degeneracies  in understanding the composition of low-mass planets. If there are not too many questions, I will also discuss the possibility of evaporation making planets that were born uninhabitable, habitable again later in their lives.

  • Lunchtime career development workshop "How to give good talks", Sarah Rugheimer

Week 4

Monday:

  • 10:00-10:30: Coffee
  • 2:00-3:0: Doug Lin, Astronomy & Astrophysics, UCSC

"Planting seeds for gravitational wave generators around active galactic nuclei: Analog of planetary systems around massive black holes.

Advanced LIGO event GW150914 has been attributed to the coalescence of two black holes with masses more than double that of most known stellar black holes. Formation of such stellar black holes directly through supernova explosions requires massive, metal-deficient progenitors.This requirement and their nearly equal masses may not be compatible with its occurrence in the local Universe.  I consider an alternative possibility which may lead to the robust production of binary black holes with masses up to a hundred solar masses in the proximity of active galactic nuclei (AGN's). I will describe some relevant mechanisms which are analogous to the astrophysics of planet formation. I will discuss the implications of this scenario in the context of structure and evolution of AGN disks including the cause of their super solar metallicity, duty cycle of their active phase, and the rapid growth of their central massive black holes.

Tuesday

  • 10:00-10:30: Coffee
  • 10:30-11:30: Kevin Zahnle, NASA Ames Research Center

"Two cute titles and a TBD."

This will touch on three topics in atmospheric escape in an order and depth yet to be determined, but likely to prove unsatisfying in all regards. "Escape from the Dead Zone" is the frightening story of how hydrogen escapes from a rocky planet in the presence of a substantial planetary magnetic field. "The Cosmic Shoreline" is a Big Picture riff on how escape in our and other solar systems appears to sculpt planets on all scales, with very little regard for our preference of physical mechanisms. The third topic, which doesn't have a catchy title yet, is a preliminary but quantitative discussion of how well molecular cooling inhibits hydrogen escape from rocky planets, as determining by examining the self-consistency of hydrostatic atmospheres.

Wednesday

  • 10:00-10:30: Coffee
  • 10:30-11:30: Yamila Miguel: Observatoire de la Côte d'Azur, Nice

"Exploring giant planet interiors and atmospheres"

Giant planets are crucial to understand the origins of planetary systems. They are the first planets to form and their interiors and atmospheres give us constrains on the physical and chemical conditions of the primitive nebula in which they were formed.
Juno mission will allow us to get better constrains on both Jupiter's internal structure and its atmosphere, and therefore a much better knowledge of the structure of giant planets. The detailed information obtained from the giant planets in our Solar system is complemented with the stunning amount of data we are obtaining from exoplanets, including key information about their atmospheres. Using and linking the information we obtain from both sides will help us to understand planetary formation and exoplanetary physics.

In this seminar, I will talk about characterization of (exo)planets through detailed interior and atmospheric models. I will show the relevance of disequilibrium chemistry in the interpretation of exoplanet atmospheres data and the effect of stellar irradiation in their atmospheres. For their interior structures, Juno will provide a new look at the interior of the planet by a combination of measurement with gravimetry, magnetic sounding and radiometry. I will show that one of the big challenges in deriving a core mass and a global composition of the planet still rests on the accuracy of equations of state. In particular, significant differences remain in recent EOSs, explaining differences seen in recently published interior models of the planet. Resolving these will greatly help the interpretation of Juno data.

Thursday

  • 10:00-10:30: Coffee
  • 10:30-11:30: Mike Liu, University of Hawaii

"Mapping Substellar Evolution with Young Gas-Giant Planets and their Free-Floating Brown Dwarf Analogs"

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 have completed a comprehensive observational study of the youngest field brown dwarfs, whose ages and masses overlap young gas-giant planets and thus are promising analogs for studying exoplanet atmospheres and evolution at high S/N and spectral resolution.  We use high-quality spectra and parallaxes (the latter from the Hawaii Infrared Parallax Program) to map the influence of temperature and gravity on ultracool objects from ~100 Mjup to ~5 Mjup. We find that young low-mass objects form a distinct sequence IR color-magnitude diagrams, distinct from the (old) field population. Current theoretical models are broadly consistent with this low-gravity sequence, though too blue and/or faint compared to the data. To provide an empirical foundation for interpreting extreme-contrast imaging surveys, we establish a grid of spectral standards and benchmarks, based on membership in nearby young moving groups of known age.  Finally, we show that the low-gravity sequence and the locus of directly imaged companions largely coincide but not entirely, suggesting the two populations may share different physical properties and/or evolutionary histories.

Friday

  • 10:00-10:30: Coffee
  • 10:30-11:30: Eva Ntormousi, CEA Saclay

"The role of magnetic fields in the formation and evolution of molecular clouds"

It has been known for a long time that stars form out of dense molecular interstellar gas, which is highly structured, turbulent and magnetized. However, the mechanisms that give molecular clouds their structure, as well as the role of turbulence and magnetic fields in regulating molecular cloud and star formation are still being debated. In this talk I will first present a model for molecular cloud formation out of the warm, atomic interstellar medium. In this model molecular clouds form rapidly and dynamically out of the fragmentation of large-scale interstellar shocks, through a combination of fluid instabilities. I will specifically discuss the role of magnetic fields in this process. In the second part I will show the results of high-resolution, non-ideal MHD simulations of molecular clouds and discuss the effects of ion-neutral friction in the properties of turbulence and in the structure of molecular clouds.

  • Lunchtime career development workshop "Job applications", Jonathan Fortney

Week 5 

Monday:

  • 10:00-10:30: Coffee
  • 10:30-11:30: Mark Marley, NASA Ames Research Center

"The Art and Science of 1D Radiative-Convective Equilibrium Models"

In almost every exoplanet atmospheres talk model temperature-pressure profiles are shown. Usually these are employed to make some point about chemistry or clouds or dynamics and just as commonly nothing at all is said about where these profiles actually come from. Yet these profiles are in reality the result of decades of focused effort and represent the culmination of hundreds if not thousands of individual decisions about how the underlying atmospheric physics should be modeled. In my presentation I will discuss both the science of atmospheric modeling and also shed some light on the numerical art that goes into the calculation of these models. I will consider questions such as, "What assumptions go into the models that produce these profiles? How are the profiles computed? How is cloud condensation handled? How robust are the conclusions?”. I’ll illustrate the discussion with results from our own atmosphere model as it has been applied through the years to atmospheres ranging from that of Titan to Uranus to the first brown dwarf to the hottest exoplanets and the coldest Y dwarf.

Tuesday

  • 10:00-10:30: Coffee
  • 10:30-11:30: Liu Hui-Gen, Nanjing University, School of Astronomy and Space Science, China

"Circumbinary Planets and Planets in Open Clusters"

Exoplanets are well detected in different stars, including binary or even triple/quadruple star systems. This is a good way to check if current planet formation and migration theories are available in these systems. This talk will focus on two issues, i. e. planets in circumbinary systems and planets in open clusters. 19 circumbinary planets have hitherto been detected, 9 of them are detected by Kepler. We present a phenomena called "tight transit events", i. e. transits with very small interval for transiting planets around binaries. The special characteristics of the light curves during "tight transit events" will benefit us to know more information about these systems for observation in the future. Further more, most stars formed in clusters, and planet formed in such environments of clusters. However, few planets are detected in clusters. We present a more real dynamical environments in open clusters, and check the orbital architecture for multi-planetary systems. We conclude how the environments influence the stability and occurrence rate of planet in open clusters.

Wednesday

  • 10:00-10:30: Coffee
  • 10:30-11:30: Bill Hubbard, University of Arizona

"Juno at Jupiter"

Following a successful injection burn on 5 July (UTC), Juno is now in a loose Jupiter orbit, to be tightened to 14-day period later. Perijove 1 with all science instruments active will occur on 27 August. I'll describe the Juno mission with a focus on the Jupiter interior modeling that we plan to do using expected gravity data of unprecedented sensitivity, constrained by elemental abundances from microwave sounding. The earliest expectation of new Jupiter gravity data is late November, so this talk will mainly be a briefing on the status of our modeling preparations.

Thursday

  • 10:00-10:30: Coffee
  • 10:30-11:30: Xi Zhang, UC Santa Cruz

"Effects of Bulk Composition on The Atmospheric Dynamics on Close-in Exoplanets"

I am going to talk about my recently submitted paper (arXiv:1607.04260). Super Earths and mini Neptunes likely have a wide range of atmospheric compositions, ranging from low-molecular mass atmospheres of H2 to higher molecular atmospheres of water, CO2, N2, or other species. The e ect of atmospheric composition and molecular mass on the transit spectra have been extensively investigated, but almost no attention has been paid to the question of how molecular mass and composition a ect the underlying atmospheric dynamics. Here, we systematically investigate the effects of atmospheric bulk compositions on temperature and wind distributions for tidally locked sub-Jupiter-sized planets, using an idealized three-dimensional general circulation model (GCM). The bulk composition effects are characterized in the framework of two independent variables: molecular weight and molar heat capacity. The effect of molecular weight dominates. As the molecular weight increases, the atmosphere tends to have a larger day-night temperature contrast, a smaller eastward phase shift in the thermal phase curve and a smaller zonal wind speed. The width of the equatorial super-rotating jet also becomes narrower and the “jet core” region, where the zonal-mean jet speed maximizes, moves to a greater pressure level. The zonal-mean zonal wind is more prone to exhibit a latitudinally alternating pattern in a higher-molecular weight atmosphere. The effects of the molar heat capacity are generally small. But if the vertical temperature profile is close to adiabatic, molar heat capacity will play a significant role in controlling the transition from a divergent flow in the upper atmosphere to a jet-dominated flow in the lower atmosphere. Six possible observables exhibit trends with molecular weight in our simulations: (I) day-night temperature difference; (II) thermal phase shift; (III) root-mean-square of the wind speed; (IV) latitudinal widths of the equatorial jets; and (V) pressure of the jet core region; and (VI) maximum zonal-mean zonal jet speed. We also present analytical theories that quantitatively explain the above trends. Those observables could be used to indirectly determine the atmospheric compositions on tidally locked sub-Jupiter-sized planets.

Friday

  • 10:00-10:30: Coffee
  • 10:30-11:30: Mariangela Bonavita, University of Edinburgh

"Early-results from SHINE, the SPHERE High-Contrast Imaging Survey for Exoplanets"

SPHERE (Spectro-Polarimetric High-contrast Exoplanet REsearch) is the new planet finder for the VLT and has been fully operational for just over a year. In this talk I will give an overview of the main properties of the instrument and present some of the first results obtained in the framework of the guaranteed time survey, SHINE. I will briefly describe the main properties of the SHINE sample, the data reduction and analysis strategy, the current detection performances achieved and finally the first results of the statistical analysis of the first year of observations.

Week 6: Fellows Presentations. 

Monday: No seminar

Tuesday

  • 10:30-11:00: Peter Gao. "Sulfur Hazes in Giant Exoplanet Atmospheres: Impacts on Reflected Light Spectra "
  • 11:00-11:30: Ryan McDonald. "Unveiling Water on Cool Giant Exoplanets: A WFIRST Story. Or: How I Learned to Stop Worrying and Harness the Clouds "
  • 1:00-1:30: Kat Feng. "Constraining Habitability with Reflected-light Observations of Another Earth"
  • 1:30-2:00: Thaddeus Komacek. "Partitioning of water between surface and mantle: what makes a waterworld?"
  • 2:00-2:30: Ashley Baker. "Assessing cloud structure using parametrized and self-consistent models in retrieval"

Wednesday

  • 10:30-11:00: Cecilia Leung. "1D Cloud Model for Terrestrial Exoplanets"
  • 11:00-11:30: Natasha Bathala. "Information Content Analysis for Optimal Selection of JWST modes"
  • 1:30-2:00: Corentin Cadiou. "The Kepler Planets: A Tale Of Evaporation"
  • 2:00-2:30: Ryan Garland. "Characterizing Cloudy L/T Dwarf Atmospheres with Bayesian Inference" 
  • 2:30-3:00: Laura Mayorga. "How Do Brown Dwarfs Grow?"

Thursday

  • 10:30-11:00: Diana Powell. "Chemical Indicators of Protoplanetary Disk Processes and Surface Density" 
  • 11:00-11:30: George MacDonald. "Investigation of the photoevaporation desert for M-dwarfs to Sun-like stars"
  • 1:30-2:00: Nestor Espinoza. "Atmospheric composition beyond the C/O ratio" 
  • 2:00-2:30: Yui Kawashima. "Impact of clouds on detecting oxygen" 
  • 2:30-3:00: Tom Louden. "SPIDERMAN vs. Wasp-43b: Creating a fast code to map the surfaces of exoplanets" 

Friday

  • 10:30-11:00: Kazumasa Ohno. "Influence of planetary obliquity on atmospheric dynamics on non-synchronized exoplanets" 
  • 11:00-11:30: Matej Malik. "The Role of Clouds in a Water Runaway Greenhouse Scenario"
  • Closing remarks.
  • Party at Jonathan's!!!!