Extrasolar Planets and Their Hosts: 0.2Cm Why Exoplanet Science

Extrasolar planets and their hosts: Why exoplanet science needs X-ray observations

Dr. Katja Poppenhaeger Sagan Fellow

Harvard-Smithsonian Center for Astrophysics Exoplanets Exoplanets in 2005

(from the Exoplanet Orbit Database) Exoplanets in 2010

(from the Exoplanet Orbit Database) Exoplanets in 2014

(from the Exoplanet Orbit Database) Exoplanets in 2014, including Kepler candidates

(from the Exoplanet Orbit Database) Exoplanets at AAS Winter meetings of the American Astronomical Society: press releases: exoplanets vs. everything else

AAS 2011 Seattle: 11% (4/38) AAS 2012 Austin: 12% (4/34) AAS 2013 Long Beach: 29% (13/45) AAS 2014 National Harbor: 31% (9/29) Exoplanets at AAS Winter meetings of the American Astronomical Society: press releases: exoplanets vs. everything else

AAS 2011 Seattle: 11% (4/38) AAS 2012 Austin: 12% (4/34) AAS 2013 Long Beach: 29% (13/45) AAS 2014 National Harbor: 31% (9/29)

100

60 %

0 2010 2012 2014 2016 2018 2020 2022 year Exoplanets at AAS Winter meetings of the American Astronomical Society: press releases: exoplanets vs. everything else

AAS 2011 Seattle: 11% (4/38) AAS 2012 Austin: 12% (4/34) AAS 2013 Long Beach: 29% (13/45) AAS 2014 National Harbor: 31% (9/29)

100

60 %

0 2010 2012 2014 2016 2018 2020 2022 year X-ray emission in exoplanet systems

central star (if cool star): magnetic activity, ﬂares planets: aurorae, charge exchange Stellar high-energy emission

stellar magnetic activity planetary atmospheres: biases planet detections use star as background candle

planetary mass loss: interactions of planets with stellar high-energy stellar rotation/activity emission is driver for evaporation Exoplanets: transits

picture credit: NASA Exoplanet atmospheres: transmission spectroscopy Exoplanet atmospheres: transmission spectroscopy

picture credit: NASA Exoplanet atmospheres: transmission spectroscopy HD 209458b (hot Jupiter)

Deming et al. 2013 Exoplanet atmospheres: cloud layers

HAT-P-12b (warm Saturn)

Line et al. 2013 Exoplanet atmospheres: cloud layers

GJ 1214b (super-earth)

Kreidberg et al. 2014 Exoplanet atmospheres: transmission spectroscopy

picture credit: NASA Exoplanet atmospheres: outer layers

Poppenhaeger et al. 2013 Exoplanet atmospheres: outer layers

Lecavelier des Etangs et al. 2010

picture credit: D. Charbonneau / Nature moving (evaporating) deeper transits atmosphere: line proﬁles X-ray transits (hot Jupiter HD 189733b)

1.10 optical data

1.05

1.00

0.95 normalized flux 0.90 X-ray transit model X-ray data 0.85

0.80 0.96 0.98 1.00 1.02 1.04 orbital phase

5 X-ray observations co-added, 0.2-2 keV Poppenhaeger et al., ApJ 2013 Atmospheric evaporation, driven by X-rays and UV

Evaporation of gaseous envelope

YOHKOH/modiﬁed by K.P.

Lopez et al. 2013 Imprints of evaporation in observed exoplanet population

Sanz-Forcada et al. 2011 Evaporating planets - transit proﬁles

KIC 12557548, dusty tail?

picture credit: NASA/JPL/Caltech Rappaport et al. 2012 Small planets can lose lots of mass

XMM detections of host stars: water-planet GJ 1214 b (Lalitha et al. 2014 submitted), rocky planet CoRoT-7 b (Poppenhaeger et al. 2012)

→ mixed systems like KOI-314? Decline of magnetic activity: magnetic braking

loss of angular momentum through stellar wind Activity decline with stellar age Star-planet interaction (template: star-star interaction in close binaries) 2 basic scenarios:

tidal magnetic spin-up (inhibited discovery papers: spin-down) of host star; Shkolnik et al. 2005, 2008 stronger for thick outer for 2 individual systems convection zones

picture credit: Shkolnik et al. 2009 Individual planet-host stars: Flare triggering?

HD 189733b (hot Jupiter)

Pillitteri et al. 2011 Stellar samples: planet-induced activity enhancements?

I searching for trends in samples of planet-hosting stars: Kashyap et al. high activity? 2010, Poppenhaeger et al. 2010, 2011, Lanza 2011, Shkolnik 2013, Miller et al. 2012, 2013, and others

I caveat: stellar activity biases against planet detection! low activity? Dealing with selection effects Dealing with selection effects Dealing with selection effects Systems with a built-in negative control: Planet-hosting stars with stellar companions

CoRoT-2 AB HD 189733 AB 55 Cnc AB

τ Boo AB υ And AB Stellar age and X-ray luminosity Stellar age and X-ray luminosity

29 X L g o l 28

27 CoRoT-2 B

HD 189733 B 26 6 7 8 9 10 log age Stellar age and X-ray luminosity

29 CoRoT-2 A X L g o l 28 HD 189733 A

27 CoRoT-2 B

HD 189733 B 26 6 7 8 9 10 log age X-ray activity for 5 systems

) 30 strong tidal interaction weak tidal interaction X L g o l ( 29 y t i s

o planet-hosting n i 28 primary m u l

y a

r primary: expected - 27 X

r secondary a l l e t

s 26

CoRoT-2 Ab B tau Boo Abups B And Ab B HD 189733 Ab B 55 Cnc Abcde B

Poppenhaeger et al. 2014, A&A Letters X-rays: exoplanets & host stars

I stars: activity biases in exoplanet samples

I stars: tidal / ﬂare triggering interactions of planets and stars

I exoplanets: short wavelengths probe outer atmospheres, via transit depths or line proﬁles

I exoplanets: X-ray/UV-driven evaporation

I upcoming opportunities: Athena+, Astro-H, eRosita

I Arcus: X-ray grating! NASA SMEX proposal: X-ray spectrograph Arcus