Atmospheric Characterization of Extrasolar Planets Ignas Snellen, - - PowerPoint PPT Presentation

Atmospheric Characterization

• f Extrasolar Planets

Ignas Snellen, Leiden Observatory

Why do we want to study exoplanet atmospheres?

X We want to understand the atmospheres of all planets (?)

Why do we want to study exoplanet atmospheres?

X We want to understand the atmospheres of all planets (?) X To understand the atmosphere of the Earth we need to understand the atmospheres of all planets (?)

Why do we want to study exoplanet atmospheres?

X We want to understand the atmospheres of all planets (?) X To understand the atmosphere of the Earth we need to understand the atmospheres of all planets (?) V Understanding planet atmospheric processes and their evolutionary histories is crucial for unambiguously identifying biomarker gases

Understanding exoplanet atmospheres an enormous challenge:

Solar system planets show immense complexity and diversity Gas giants: H2-dominated; clouds; strong zonal flows; storms Rocky planets: very diverse

Understanding exoplanet atmospheres an enormous challenge:

Solar system planets show immense complexity and diversity Rocky planets: secondary atmospheres -- very diverse

Super-rotating, CO2 based Opaque sulfuric acid clouds Partially clear, N2-based Biotic oxygen Tenuous CO2 Varying trace-amount of methane

Current Status:

“Trying to comprehend Darwinian evolution using three animals”

First impressions from exoplanet population: even more diversity!

• Hot Jupiters
• Super-Earths – mini-Neptunes
• Gas giants at large orbital distances
• Requirement:

study large samples, including all planet types from gas giants to rocky planets, in a wide range of orbits around stars varying in mass, metallicity, and age.

Exoplanet challenge

You visit You dig and drill in situ measurements

Understanding planets

• Body’s mass, size
• Composition of atmosphere, surface
• Rotation period, oblateness
• Gravity field, magnetic field
• Seismic data
• Laboratory data behaviour of materials
• Quantum mechanical calculations

Possible hard too difficult? Impossible!

Exoplanets

Atmospheric Characterization

Understanding the 3D climate

absorbed stellar flux, reradiated back in space, intrinsic heat T/p profile, set by stellar incident energy, abundances

• f spectroscopically active molecules, hazes/clouds

Rotation and atmospheric circulation

Studying exoplanet atmospheres

It’s all about separating the planet from the star!

Filtering Observing Technique

Time domain Transits, eclipses, phase curves Spatial domain High Contrast Imaging (HCI) Spectral+Temporal High Dispersion Spectroscopy (HDS) Spectral+Spatial domain HDS+HCI

Temporal separation

transmission spectroscopy eclipse spectroscopy

HD 189733b - Pont et al. 2012 Cloud deck?

Deming et al. 2013

Temporal separation

Stevenson et al. 2014

Time domain: pushing towards smaller planets super-Earth regime

GJ1214: Kreidberg et al. 2014

James Webb Space-based Time Domain: Nikolay Nikolov talk Ashlee Wilkins talk David Ehrenreich Talk

Using Time Domain is challenging from the ground

Measure <10-3-4 variations in flux as function of λ over 1-5 hour time scales

Transits and Secondary Eclipses

Earth Atmosphere:

• Variations in turbulence / seeing
• Variations in absorption & scattering
• Variations in thermal sky emission

Instrumental:

• Variations in gravity vector or field rotation
• Variations in thermal behaviour

Using Time Domain is challenging from the ground

Measure <10-3-4 variations in flux as function of λ over 1-5 hour time scales Transits and Secondary Eclipses

Observe target + reference stars simultaneously

• Atmospheric variations similar for target & refs
• Different optical paths through telescope + instruments

Bean et al., Nature 2010

GJ1214b Talks: Louden, Lendl Poster on FORS2 by Boffin

Spatial Separation High Contrast Imaging

young, self-luminous planets: SPHERE, GPI & Subaru are state-of-the-art

Quanz et al. 2013

Adaptive Optics - Planet flux D2 Coronagraphy - resolution D-1 Smart algorithms - background Constant

• cooler planets brighter longer wavelengths

Talks yesterday!

Top METIS Science Case High Contrast Imaging (HCI)

Planets are ubiquitous target the nearest stars Evolved planets have cooled down wavelengths

Spectral + Temporal Separation HDS

Hot Jupiters: CRIRES is state-of-the-art

Talks by: A Wyttenbach Jayne Birkby

• J. Martins

Emanuele di Gloria (using the chromatic RM effect)

CRIRES+: probing above the cloud deck

HDS probes the atmosphere at lower pressures than low-res spectroscopy

Spectral + Spatial Domain: HDS + HCI

Beta Pictoris b Talk by Henriette Schwarz

Top METIS Science Case HDS + HCI Atmospheric characterization of nearby rocky planets

METIS IFU Snellen et al. 2015

0.1 Ms 1 Ms 3 Ms

M5 G2 A5

0.1 AU 0.3AU 1 AU 3 AU

M2 0.3 Ms

R a d i a l V e l

• c

i t y Transit

Orbit

0.1 Ms 1 Ms 3 Ms

M5 G2 A5

0.1 AU 0.3AU 1 AU 3 AU

M2 0.3 Ms

R a d i a l V e l

• c

i t y Transit

Orbit

Great Future Ahead!

• Time Domain: transits and eclipses

JWST let’s get organized!

• Spatial Domain: High Contrast Imaging

SPHERE, GPI, Subaru

JWST METIS@ELT, EPICS…

• Spectral + Time Domain: High Dispersion Spectroscopy

ESPRESSO and CRIRES+

E-ELT: METIS and HIRES

• Spectral + Spatial Domain: HDS + HCI

CRIRES+ E-ELT: METIS (and HIRES?) Ian Crossfield’s talk