How Do We Fit In? Comparative Planetology and LUVOIR

Eliza Kempton (Formerly: Miller-Ricci) Assistant Professor of Physics Assistant Professor of Astronomy Grinnell College, Grinnell, IA University of Maryland, College Park

Exoplanet detections over the last 20 years have revealed a diversity of planetary systems

Radial Velocity Transit Microlensing Solar System

E Exoplanet detections over the last 20 years have revealed a diversity of planetary systems

Radial Velocity Transit Microlensing Solar System

Atmospheric E characterization efforts have been primarily limited to close-in transiting exoplanets Exoplanets have diverse bulk compositions, which reﬂect their formation histories

Hadden & Lithwick, AJ, 2017 Current examples of comparative exoplanetology studies

Planetary mass-metallicity relationship: Figure c/o Jacob Bean Jacob c/o Figure

Exoplanet data: Theoretical models: Kreidberg et al. 2014b, Fraine et al. 2014, Kreidberg et Fortney et al. 2013 – 100 km planetesimals al. 2015, Line et al. 2016, Stevenson et al. 2017, Wakeford et al. 2017 Current examples of comparative exoplanetology studies

A continuum of clear to cloudy hot Jupiter atmospheres:

Sing et al., Nature 2016 Current examples of comparative exoplanetology studies

Atmospheric trends in Neptune-size exoplanets:

Crossﬁeld & Kreidberg, ApJL 2017 Future atmospheric characterization of exoplanets with LUVOIR will extend these efforts into regions of parameter space that are currently untapped

Radial Velocity Transit Microlensing Solar System

J • Longer period planets • Low-mass planets • Debris disks + complementary observational E techniques: • Reﬂected light spectroscopy Future atmospheric characterization of exoplanets with LUVOIR will extend these efforts into regions of parameter space that are currently untapped

Radial Velocity Transit Microlensing Solar System

J • Longer period planets • Low-mass planets • Debris disks Exoplanet studies with LUVOIR + complementary observational E techniques: • Reﬂected light spectroscopy Challenges for LUVOIR: Precise planetary orbits, masses, and radii

Rocky planet, Volatile-rich water outgassed H2-rich world, water-rich atmosphere atmosphere

Natasha Batalha, Kempton, & Mbarek, ApJL, 2017 Challenges for LUVOIR: Precise planetary orbits, masses, and radii

Rocky planet, Volatile-rich water outgassed H2-rich world, water-rich atmosphere atmosphere

Natasha Batalha, Kempton, & Mbarek, ApJL, 2017

Degenerate interpretations must be overcome to produce unique constraints on atmospheric properties. LUVOIR will measure masses and orbits astrometrically. Radii are harder… Opportunity: Provide context for studies of habitable exoplanets

e.g. a statistical test for the habitable zone hypothesis:

Habitable zone trend of CO2 vs. irradiation for planets w/ active carbonate-silicate cycles

Bean, Abbot, Kempton ApJL, 2017 Opportunity: Reﬂected light spectroscopy of exoplanets

hydrocarbon haze – 0.3 FGJ1214b

salt & sulﬁde clouds 0.3 FGJ1214b

water clouds

Morley et al. ApJ, 2015 Opportunity: Reﬂected light spectroscopy of exoplanets

0.2 Earth 0.5 Venus

0.4 0.15 ) ) 9 9 0.3 0.1 (x10 (x10 s s

/ F / F 0.2 p p F F 0.05 0.1

0.0 0.0 0.5 1.0 1.5 2.0 2.5 3.0 0.5 1.0 1.5 2.0 2.5 3.0 Wavelength (μm) Wavelength (μm)

70 Warm Jupiter at 0.8 AU 14 Earth 60 warm Jupiter at 0.8 AU warm Jupiter at 2.0 AU 12 50 10 ) ) 9 9 40 8 (x10 (x10 s s 30 6 / F / F p p F F 20 4

10 2

0 0 0.5 1.0 1.5 2.0 2.5 3.0 0.5 1.0 1.5 2.0 2.5 3.0 Wavelength (μm) Wavelength (μm) In summary…

For the ﬁrst time, LUVOIR will extend comparative planetology to the realm of directly imaged exoplanets, providing the necessary context for studies of habitable worlds