ÉPPÉ: Extrasolar Polarimetry Explorer / Explorateur Polarimétrique des Planètes Extrasolaires

UWO: Stanimir Metchev, Paulo Miles-Páez McGill: Nicolas Cowan, Taylor Bell NRC: Christian Marois Magellan Aerospace: Warren Soh (Technical Lead), Jennifer Michels, Eric Choi ABB: Jean-François Lavigne, Frederic Grandmont Visual Voice Gallery: Bettina Forget

Funded by the CSA through the RFP for Space Exploration Concept Studies for Planetary Exploration and Space Science Priorities ÉPPÉ: a proposed microsatellite for characterization Notional design

• D = 30 cm

• � = 300 – 800 nm

• 60x60x60 cm, 22 kg

• low-Earth orbit

• differential polarimetry

• unique space-based capability

• pathfinder for biomarker detection on Image Credit: CC BY-SA 3.0 Luciano Mendez Exoplanet characterization is a top astrophysical priority

• CASCA 2011–2020 Long Range Plan and 2016–2020 Mid-term Review

• 2016 CSEW Topical Team reports:

• Space Astronomy – Origins

• Planetary Systems –

• NASA: Exoplanet Exploration Program

• US National Academies “Exoplanet Science Strategy”

• ESA: Cosmic Vision 2015–2025 “ and Life” theme Image credit: https://exoplanets.nasa.gov Precision Exoplanet Missions photometry, spectroscopy

MOST

CoRoT

ARIEL

>3500 exoplanets ~5 Earth analogues 4 Limitations of precision photometry/spectroscopy

• Clouds, hazes: GJ 1214b super-Earth • prohibit spectroscopic feature detection

• vetting prior to detailed spectroscopy is critical

• Instrument systematics:

• ~20–30 ppm noise floor for HST, JWST set by inter-pixel de-correlation residuals

• can not be overcome with more observations Kreidberg et al. (2014) Simultaneous 1 milliarcsecond differential polarimetry

• Is uniquely sensitive to polarized scattered

• clouds, hazes

• Overcomes de-correlation noise floor via simultaneous measurements of orthogonal polarizations

(Berdyugina 2011) Simultaneous differential polarimetry

• Is uniquely sensitive to polarized scattered light

• clouds, hazes

• Overcomes de-correlation noise floor via simultaneous measurements of orthogonal polarizations Simultaneous differential polarimetry

• Is uniquely sensitive to polarized scattered light

• clouds, hazes

• Overcomes de-correlation noise floor via simultaneous measurements of orthogonal polarizations Simultaneous differential polarimetry

• Is uniquely sensitive to polarized scattered light at a=0.04 AU • clouds, hazes a=0.11 AU • Overcomes de-correlation noise floor via simultaneous measurements of orthogonal polarizations

(Seager et al. 2000) Simultaneous differential polarimetry with photoelastic modulators (PEMs)

• PEMs are birefringent crystals resonantly driven to change retardance at 10’s kHz

• rapid switch:

• eliminates time delay from use of rotating half-wave plate

• eliminates non-common path

• greatly reduces electronic noise

• Attained precision from ground:

• 60 ppm at 3� (HD 189733b upper APD 2 APD 1 limit; Wiktorowicz et al. 2015) Sketch of the POLISH PEM-based • Limiting factor: photon noise on the Palomar 5 m telescope (Wiktorowicz et al. 2008) Simultaneous differential polarimetry with photoelastic modulators (PEMs)

• PEMs are birefringent crystals resonantly driven to change retardance at 10’s kHz

• rapid polarization switch: HD 189733b 3σ upper limit • eliminates time delay from use of rotating half-wave plate hot Jupiter at a=0.04 AU

• eliminates non-common path a=0.11 AU

• greatly reduces electronic noise

• Attained precision from ground:

• 60 ppm at 3� (HD 189733b upper limit; Wiktorowicz et al. 2015)

• Limiting factor: photon noise (Seager et al. 2000) ÉPPÉ Goals

• Technical goal: 1 ppm 1� precision Science goal: aerosol detection in exoplanets • Detect top 3–5 currently known Earth analogues; more from TESS, CHEOPS • Hot jupiters, neptunes, super-earths; not limited to transiting geometry

HD 189733b 3σ upper limit -band polarization -band R

potentially habitable Fractional Fractional

Simulations: Paulo Miles-Páez (UWO) The future: biomarker detection with space-based spectropolarimetry

ÉPPÉ future region Miles-Páez et al. 2014 wavelengths of interest

Miles-Páez et al. (2014) Precision Exoplanet Missions photometry, spectroscopy

MOST

CoRoT

ARIEL

>3500 exoplanets 14 ~5 Earth analogues Precision Exoplanet Missions photometry, spectroscopy, polarimetry MOST

CoRoT

ÉPPÉ ARIEL

>3500 exoplanets 15 ~5 Earth analogues ÉPPÉ: a proposed concept for a Canadian trademark exoplanet mission

• Built with polarimetry in mind

• lowest possible level of instrument systematics

• unexplored domain of space-based exoplanet science

• complementary to precision photometry and spectroscopy (JWST, CHEOPS, CASTOR)

• Dedicated to exoplanets

• long-duration stares of >10–100 exoplanet orbits: unique resource for characterization

• space-based location: UV, IR atmosphere characterization

• A Canadian trademark

• builds on tested architectures: MOST, BRITE

• pathfinder to bigger future space missions: astrobiology

Concept Study kick-off: Nov 8, 2018 (tomorrow) ÉPPÉ: a proposed concept for a Canadian trademark exoplanet mission Notional design Image Credit: CC BY-SA 3.0 Luciano Mendez

• D = 30 cm

• � = 300–800 nm

• 60x60x60 cm, 22 kg

• low-Earth orbit

• differential polarimetry

• unique space-based capability

• pathfinder for biomarker detection on exoplanets