TRAPPIST-1 & SPECULOOS planets

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NASA APAC Mee)ng, 24-25 April 2017, NASA HQ, Washington DC, USA

TRAPPIST-1 & SPECULOOS planets A chance to detect chemical traces of life beyond our solar system

Michaël Gillon (Liège) University of Liège, Belgium

Search for habitable Planets EClipsing ULtra-cOOl Stars



Search for habitable Planets EClipsing ULtra-cOOl Stars

What are « ultra-cool stars »? Ultracool dwarfs: Teff < 2700K, spectral type later than M6 Sun (Kirckpatrick et al. 1995).

Mix of stars + brown dwarfs

Ultra-cool star

hBp://www.stsci.edu/~inr/ldwarf3.html



Search for habitable Planets EClipsing ULtra-cOOl Stars

What are « ultra-cool stars »? Ultracool dwarfs: Teff < 2700K, spectral type later than M6 Sun (Kirckpatrick er al. 1995).

Mix of stars + brown dwarfs Ultra-cool star

Ultracool (dwarf) stars Spectral type: M7V to L2.5V (Dieterich et al. 2014)

Mass: 0.075 to 0.1 M¤ Size: 0.08 to 0.15 R¤ Luminosity: 0.01 to 0.1% L¤ Main-sequence lifeLme: >1000 Gyrs

Dieterich et al. (2014)



Search for habitable Planets EClipsing ULtra-cOOl Stars

Why a transit survey targeLng ultra-cool stars? 1. Uncharted territory Sun

U C S

0.01

0.1

MEarth K2 TESS PLATO etc

1 Host star mass (M¤)

10



Search for habitable Planets EClipsing ULtra-cOOl Stars

Why a transit survey targeLng ultra-cool stars? 2. Significant fracLon of the galacLc populaLon Sun

10-15% of stars in solar neighborhood



Search for habitable Planets EClipsing ULtra-cOOl Stars

Why a transit survey targeLng ultra-cool stars? 3. Habitable zone is VERY close to the star

Orbital period of a few days + Transit probability of a few %



Search for habitable Planets EClipsing ULtra-cOOl Stars

Why a transit survey targeLng ultra-cool stars?

4. Atmospheric characterizaLon of HZ Earth-sized planets possible Sun

UCS

Earth-twin - 10pc – JWST - 200hr

From Kaltenegger & Traub (2009)

Best targets for JWST : ~1000 ultra-cool stars with Jmag < 14



Search for habitable Planets EClipsing ULtra-cOOl Stars

SPECULOOS: basic concept Targets: 1000 ultra-cool dwarfs of J