Week 1 Conference

KSPA 2016 Conference: Exoplanetary Atmospheres

Santa Cruz, June 20th - June  24th 2016.

A conference is hosted in the first week of the Kavli Summer Program, and features invited pedagogical lectures in the morning, with afternoon contributed talks presenting state-of-the-art research on the program topic. Participation to the conference is open to everyone who wishes to attend. There is a $150 registration fee for attendees who are only coming for the first-week conference, to cover the meals, coffee breaks and reception costs. 

The morning lectures are video-recorded, and meant for a broad audience. The afternoon talks are typically 20-25 minutes long each, and present the latest developments in the field. All presentations will be published online a few weeks after the conference.

More detail about the upcoming conference will be posted as the organization of the program proceeds.

Scientific Program

Sunday 6/19:

 

All the talks will be hosted in the SOE Simularium (E2-180) at the bottom of the E2 building (the nice shiny one) of the Baskin School of Engineering

Monday 6/20: 

  • 8:45 am Arrive at the Simularium
  • 9:00 am - 9:30 am: Welcome words and basic information
  • 9:30 am - 1:00 pm: Lectures
  • 1:00 pm - 2:30pm: Lunch break
  • 2:30 pm - 3:30pm: Orientation; Visit of campus;
  • 3:30 pm - 4:00 pm: Afternoon Break
  • 4:00 pm - 5:30 pm: Project presentations

Tuesday 6/21:

Wednesday 6/22:

Thursday 6/23:

Friday 6/24:

 

 

Dorian Abott

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Title: Gaining insight from idealized models

Date of Talk: Wednesday, June 22, 2016

Abstract: Don't ever believe the results of a fancy model unless you can explain them using a simple model that contains only the essential elements for the story. Easier said than done! Building and using idealized models is an art. It comes more easily to some people than others, but we can all get better at it. Most importantly, it takes the courage to be outrageously wrong sometimes! I think it's worth using idealized models sometimes, and I'm going to explain a problem where they can be useful.

 

 

 

 

Jacob Bean

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Title: Observation of Exoplanet Atmospheres

 

Lecture 1

 

 

 

 

 

 

 

 

 

Lecture 2

 

 

 

 

 

 

 

 

 

Lecture 3

 

 

 

Jasmina Blecic

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Title: Exoplanetary atmospheres through the eyes of retrieval

Date of Talk: Wednesday, June 22, 2016

Abstract:There are two general approaches in modeling exoplanetary atmospheres. First is a theory-driven approach, that relays on the known chemical and physical processes in the planetary atmosphere to generate model spectra, and subsequently compare them to observations by fitting basic atmospheric parameters. Second is a data-driven approach, that priorities observations by adopting only few assumptions about the atmospheric chemistry and thermal structure, producing an unbiased estimate of the planetary atmospheric properties. By using a statistical algorithm to explore the phase space of the parameters, this approach accounts for the uncertainties resulting from our limited knowledge of chemical, dynamical, and cloud formation processes in their atmospheres. I will present the state-of-the-art retrieval frameworks BART and Pyrat-Bay and their applications to hot-Jupiter atmospheres. To asses possible limitations of the 1D retrieval approach, I will present the preliminary results on what part of the the 3D thermal structure can be revealed with 1D retrieval. Finally, I will propose several projects that will make additions to the existing retrieval framework, furthering our knowledge of exoplanetary atmospheres. The developed projects will be made available to the scientific community, promoting the idea of the reproducible research, and allowing others to extend and advance on our research.

 

 

 

 

David Catling

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Lecture 1 Title: Atmospheric Composition and Chemistry

 

 

 

 

 

 

 

 

 

 

 

Lecture 2 Title: Climate and Radiation. 

Note that the recording system accidentally crashed after the first 20 minutes of this lecture, so the end is missing.

 

 

 

 

 

 

 

 

 

 

 

Lecture 3 Title: Atmospheric evolution (mainly rocky planets)

 

 

 

 

Marko Gacesa

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Title: The role of cross sections in modeling exoplanetary atmospheres

Date of Talk: Friday, June 24, 2016

Abstract: Interpretation of observations of extrasolar planets – by current and next generation of instruments – depends on theoretical and computational models, including the models of their atmospheres. A key component in such models are cross sections that contain the physics of photochemical and kinematic processes in atmospheric gases. The prediction of phenomena of interest to planetary scientists and astrophysicists – such as atmospheric escape and evolution, existence of habitable zone, and presence of physical conditions required for supporting life – depend on our understanding of cross sections. In this talk, I will briefly illustrate the differences between several levels of theory used to calculate cross sections and dynamics for particle-particle scattering for simple (and reasonably well understood) atmospheric species. I will also show a specific example of non-thermal escape of neutrals from Mars' atmosphere and suggest possible directions of study related to hydrogenic exoplanetary atmospheres.

 

 

 

 

Colin Goldblatt

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Title: A quick look at the controls on Earth-like planet atmospheres. ​

Date of Talk: Wednesday, June 22, 2016

Abstract: The atmosphere of Earth, the interface between the surface and the Cosmos, is part of the biosphere (Vernadsky, 1926).​ Water vapour is the only gas for which the dominant control on atmospheric abundence is physical. For every other gas, the controls are a mix of biological, geological and photochemical. That is, simple chemical or physical principles fail miserably for all other important gases in the terrestrial atmosphere (e.g. N2, O2, CO2, CH4, N2O,...). Oxygen evolution is well understood, with a transition from parts per million to percent concentration 2.4 billion years ago, some hundreds of millions of years after the origin of oxygenic photosynthesis. Nitrogen evolution is not understood. Carbon dioxide is involved in climate feedbacks which are less well understood than the textbooks say. Given that atmospheric composition determines the climate, it determines habitability. Thus there is a an "inhabitance paradox": the inhabitants of the planet (life) determine whether it is habitable. So: caution exoplanet scientists! Applying simple thinking, missing intuition for biology and geology, may lead you astray.

 

 

 

 

Kaitlin Kratter

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Title: Kepler 444: lots of planets, not so much atmosphere

Date of Talk: Thursday, June 23, 2016

Abstract: Kepler has helped to change our understanding of planet formation by providing examples of exoplanets living in extreme environments.  We can use these odd-balls to better understand planet formation around normal stars. I will describe one unusual system, Kepler 444, and show how this can help us understand a possibly common mode of formation.

 

 

 

 

Laura Kreidberg

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Title: New Dimensions of Climate: Exploring Hot Jupiter Atmospheres in 3D with HST and Spitzer 

Date of Talk: Thursday, June 23, 2016

Abstract: Measurements of exoplanet thermal structure constrain the physics of atmospheric heat circulation and reveal planetary climate. In this talk, I will present results from an intensive space-based observational campaign exploring the thermal structure of two hot Jupiters, WASP-103b and WASP-18b. This program combines the new technique of phase-resolved HST/WFC3 spectroscopy with Spitzer eclipse mapping, to yield the first constraints on temperature structure as a function of latitude, longitude, and altitude. I will discuss how these detailed measurements shed new light on several currently debated features of hot Jupiter atmospheres, including blackbody dayside spectra and carbon-rich compositions. 

 

 

 

 

Michael Line

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Title: Characterizing Physical Processes in Brown Dwarf Atmospheres

Date of Talk: Tuesday, June 21, 2016

Abstract: Recent advances in atmospheric retrieval techniques applied to brown dwarf spectra have allowed us to extract detailed information about their thermal structures and molecular abundances beyond the classic “logg-Teff” grid model fits. With these new diagnostic modeling tools we can gain a deeper understanding of the physical and chemical processes operating in substellar atmospheres. From brown dwarf spectra we are able to determine metallicities, C-to-O ratios, ages, thermal structures, and compositional trends. This investigation demonstrates the power of atmospheric retrieval tools applied to high quality spectra of small sample of objects and lay’s the groundwork for future studies involving brown dwarfs,self-luminous directly imaged planets, and upcoming hi-quality transiting planet data from JWST and beyond.

 

 

 

 

Michael Liu

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Title: Near-IR Spectra of Young Imaged Planets and Brown Dwarfs"

Date of Talk: Thursday, June 23, 2016

Abstract:

 

 

 

 

Eric Lopez

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Title: Born Dry: Kepler's Ultra-Short-Period Planets formed Without Water

Date of Talk: Friday, June 24, 2016

Abstract: Recent surveys have uncovered an exciting new population ultra-short-period planets with orbit periods less than a day. These planets typically have radii less than 1.5 Earth Radii, indicating that they likely have rocky compositions. This stands in contrast to the overall distribution of planets out to ~100 days, which is dominated by low-density sub-Neptunes above 2 Earth radii, which must have gaseous envelopes to explain their size. However, on ultra-short-period orbits, planets are bombarded by huge amounts of photo-ionizing radiation and gaseous sub-Neptunes are extremely vulnerable to losing their envelopes to atmospheric photo-evaporation. Using models of planet evolution, I will show that the rocky USP planets can easily be produced as the evaporated remnants of sub-Neptunes with H/He envelopes. Critically however, the USP planets could not have lost their envelopes if they formed with very high-metallicity water dominated envelopes, indicating that these planets likely formed within the snow-line.

 

 

 

 

Mark Marley

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Title: Characterizing Cool Giant Planets in Reflected Light

Date of Talk: Tuesday, June 21, 2016

Abstract: While the James Webb Space Telescope will detect and characterize extrasolar planets by transit and direct imaging, a new generation of telescopes will be required to detect and characterize extrasolar planets by reflected light imaging. NASA’s WFIRST space telescope, now in development, will image dozens of cool giant planets at optical wavelengths and will obtain spectra for several of the best and brightest targets. This mission will pave the way for the detection and characterization of terrestrial planets by the planned LUVOIR or HabEx space telescopes. In my presentation I will discuss the challenges that arise in the interpretation of direct imaging data and present the results of our group’s effort to develop methods for maximizing the science yield from these planned missions.

 

 

 

 

Kristen Menou

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Title: Atmospheric Circulation of Exoplanets
Lecture 1

 

 

 

 

 

 

 

 

 

 

Lecture 2

 

 

 

 

 

 

 

 

 

Lecture 3

 

 

 

Yamila Miguel

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Title: "From giant planet interiors to atmospheres"

Date of Talk: Tuesday, June 21, 2016

Abstract: The key to understand the history of a planetary system is in the interiors and atmospheres of its giant planets. They are the first planets to form and their compositions give us constrains on the physical and chemical conditions of the primitive nebula in which they were formed. 

Next July the arrival of Juno mission to Jupiter 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. This 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 talk, I will present the work I've been doing in characterization of (exo)planets through detailed interior and atmospheric models. I will show how the resulting internal structure of giant planets is affected by key input parameters and its dependence on observational constrains. I will also present my work on exoplanet atmospheres linking the astrophysics observables with the atmospheric signatures expected, which facilitates the interpretation of current and future observations.

 

 

 

 

Ruth Murray-Clay

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Title: A Framework for Thermal Atmospheric Escape

Date of Talk: Tuesday, June 21, 2016

Abstract: Planetary atmospheres---particularly those hosted by Earth and super-Earth-mass planets---are sculpted by atmospheric escape. For example, terrestrial planets quickly lose primordial hydrogen, while Jupiters remain bound even on short-period orbits. The physical regime in which thermal atmospheric escape occurs depends on a planet's size, mass, and irradiative environment. I will present a framework for determining this physical regime as a function of planetary and stellar parameters. I will use hydrogen loss as an example and discuss implications for loss of hydrogen from super-Earths and mini-Neptunes.

 

 

 

 

James Owen

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Title: "The birth of planetary atmospheres: the boil-off phase"

Date of Talk: Friday, June 24, 2016

Abstract: We have now reached the point where observational knowledge of both the planet forming environments (the protoplanetary discs) and the exoplanet population give us a reasonable understanding of both the initial conditions of planet formation and the final outcome. I will show how one of the standard results from protoplanetary disc observations/theory - the rapid dispersal of the inner disc - leads to a phase where the internal luminosity of the formed planet powers a strong outflow, causing it to lose much of the atmosphere it originally accreted. I will argue this processes, which we dub "boil-off" could strongly shape the exoplanets we see today.

 

 

 

 

Tyler Robinson

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Title: Characterizing and Modeling (Exo)Planetary Atmospheres

Date of Talk: Tuesday, June 21, 2016

Abstract: Exoplanetary atmospheres is an exploding and (as participants of this program will agree) exciting area of study. To best enable collaborations, this presentation will focus on tools and approaches I have developed and am pleased to share over the coming month. These include data and models from analog studies of key Solar System worlds (e.g., Earth and Titan). I will briefly discuss a coronagraph instrument noise model that can be used in feasibility studies related to WFIRST, HabEx, and/or LUVOIR. Finally, I will introduce a generalized, full-physics exoplanet spectral model, capable of generating reflected-light, emission, and/or transit spectra for a variety of worlds.

 

 

 

 

Sarah Rugheimer

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Title: Impact of UV on Characterizing the Spectral Fingerprints of Earth-like Planets

Date of Talk: Wednesday, June 22, 2016

Abstract: The spectral type of the host star will influence our ability to detect atmospheric features with future space and ground based missions like JWST, GMT and horizon direct detection missions like HDST/LUVOIR.Specifically, the UV emission from a planet’s host star dominates the photochemistry and thus the resultantobservable spectral features. Using the latest UV spectra obtained by HST as well as IUE, we model Earth-like planets for a wide range of host stars and geological epochs from pre-biotic to modern Earth-like biology. We detail the results of stellar activity on the primary detectable atmospheric features that indicate habitability on Earth, namely: H2O, O3, CH4, N2O and CH3Cl. Our model spectra of terrestrial planets spans a grid of FGKM host stars and is presented for the VIS/NIR (0.4 μm - 4 μm) and the IR (5 μm - 20 μm) wavelengths.

 

 

 

 

Andrew Skemer

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Title: Characterizing the Coldest Exoplanets

Date of Talk: Thursday, June 23, 2016

Abstract: The giant planets of our own Solar System are much colder than the exoplanets that we can study with current technology.  Thermal infrared observations (3-5 microns) have the potential to advance the field of exoplanet characterization towards colder objects.  By pushing current instrumentation to new limits, and developing new technologies, I will describe a program to characterize the coldest exoplanets and brown dwarfs in the thermal infrared, including the first spectrum of the coldest object outside of our Solar System.

 

 

 

 

Andrew Youdin

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Title: On the Anomalous Radii of Hot Jupiters

Date of Talk: Friday, June 24, 2016

Abstract: The large transit radii of short-period Jovian-mass exoplanets is a longstanding puzzle.  I will provide a brief overview of proposed solutions to this so-called “embiggening.”  I will discuss the role of turbulence in the radiative layers of Hot Jupiters and summarize the results of recent evolutionary calculations by (Kavli participant) Thaddeus Komacek.

 

 

 

 

Kevin Zahnle

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Title: Another Green World

Date of Talk: Wednesday, June 22, 2016

Abstract: The conventional habitable planet is an Earth-like aqua world with a liquid water ocean and pleasant sandy beaches. The inner edge of the aqua planet's habitable zone is where the oceans evaporate in a catastrophic runaway greenhouse. This happens because there is an upper limit, called the critical flux, on how much thermal radiation can be emitted by a saturated water vapor atmosphere. A second class of habitable planet is the land planet, a desert world with relatively little water and unpleasant sandy wastes. Open water is restricted to cold traps, probably polar. Land planets are less familiar than aqua planets but are not necessarily any rarer in the cosmos; in our own Solar System, both Mars and Titan (with methane playing the role of water) exhibit some of the properties of land planets. The planet Arrakis, also known as Dune, is a well-known fictional example of a land planet. The important property of a land planet is that it is dry enough that water almost never condenses in the tropics. The tropical atmosphere is therefore truly dry and the critical flux does not apply there. This allows the land planet to radiate more thermal energy than an aqua planet, which makes the land planet more resistant to runaway. As the Sun evolves and brightens, the land planet remains habitable much longer than does the comparable aqua planet. It may be possible for an aqua planet to evolve into a land planet without experiencing a catastrophic runaway greenhouse effect.

 

 

 

 

Xi Zhang

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Title: Effects of Bulk Composition on the Atmospheric Dynamics on Close-in Exoplanets

Date of Talk: Thursday, June 23, 2016

Abstract: Depending on the metallicity of the protoplanetary disk, the details of gas accretion during planetary formation, and atmospheric loss during planetary evolution, the atmospheres of sub-Jupiter-sized planets could exhibit a variety of bulk compositions. Examples include hydrogen-dominated atmospheres like Jupiter, more metal-rich (but still hydrogen-dominated) atmospheres like Neptune, evaporated atmospheres dominated by helium, or of course carbon dioxide, water vapor, nitrogen, and other heavy molecules as exhibited by terrestrial planets in the solar system. In this study we systematically investigate the effects of atmospheric bulk compositions on temperature and wind distributions for tidally locked sub-Jupiter-sized planets such as super-Earths and mini-Neptunes, using an idealized three-dimensional general circulation model (GCM). Composition—in particular, the molecular mass and specific heat—affect the sound speed, gravity wave speeds, atmospheric scale height, and Rossby deformation radius, and therefore in principle can exert significant controls on the atmospheric circulation, including the day-night temperature difference and other observables. We performed numerous simulations exploring a wide range of molecular masses and molar specific heats and provided analytical theories to explain aspects of the simulations relevant for possible observables on tidally locked exoplanets, such as the day-night temperature difference, thermal phase shift and root-mean-square of the wind speed. Our analytical predictions are quantitatively compared with our numerical simulations and may provide potential indicators for determining the atmospheric compositions in future observations.