Characterising the Atmospheres of Transiting Exoplanets

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Characterising the Atmospheres of Transiting
Exoplanets Today
Giovanna Tinetti Royal Society/University
College London
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Deming et al., 2005 Charbonneau et al., 2005
Charbonneau et al., 2002
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Combined light star-planet
Harrington et al., 2006
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HD209458b,HD189733b,XO-1b
HD 209458b Mass 0.69 Mj Radius 1.32
Rj Parent star G0 Distance 0.045 AU HD
189733b Mass 1.15 Mj Radius 1.156
Rj Parent Star K1-K2 Distance 0.0312
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Seager Sasselov, ApJL, 2000
UV-VISBrown, ApJ,
2001
VIS-NIRTinetti et
al., ApJL, 2007 Kipping Tinetti, in prep
Mid-IR
Probing the terminator with transmission
spectroscopy
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Probing the day side
O3

• Sensitive to temperature
• Sensitive to vertical distribution of gases

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Sodium
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Na in the atmosphere of Hot-Jupiters


Ground-based observations
Hubble-STIS
Snellen et al., 2008 Sing et al., 2008
Redfield et al., 2007
589. nm Wavelength (nm)
Charbonneau et al., 2002
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C/O ratio solar
The chemistry of Hot-Jupiters
CO
CO2

• Photochemistry
• predicted with Kinetics
• (Liang et al., 2003,2004)
• Zanhle et al., 2009

H2O
C2H2
CH4
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Water
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IRAC transmission band-photometry
Water line list BT2 Barber et al., 2006
Beaulieu et al., 2007
Knutson et al., 2007
Water T-P 1200 K _at_ 1 bar, 700 K _at_ mbar
HD189733b, terminator
Tinetti et al., Nature, 2007
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IRAC transmission band-photometry
HD209458b, terminator
Water T-P 2500 K _at_ 1 bar, 1700 K _at_ mbar
Beaulieu, Kipping, Batista, Tinetti, Ribas et
al., submitted
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Methane
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NICMOS transmission spectroscopy
HD189733b, terminator
Swain, Vasisht, Tinetti, Nature, 2008
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UV-IR transmission spectroscopy
Swain et al., 2008
Redfield et al., 2007 Na from the ground
Knutson et al., 2007
Beaulieu et al., 2007
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NICMOS transmission spectroscopy
HD209458b, terminator
H2O
CH4
Deroo, Swain, Tinetti, Griffith, Vasisht, in prep
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NICMOS transmission spectroscopy
CH4
H2O
XO1b, terminator
Tinetti, Swain Deroo, Vasisht, Griffith et al.,
in prep
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Carbon Dioxide
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NIR emission spectroscopy NICMOS
HD189733b, day-side
H2O
CH4
CO2
CH4
Swain, Vasisht, Tinetti et al., ApJL, 2009
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NIR-MIR emission spectroscopy
HD189733b, day-side
NICMOS, Swain et al., 2009
CH4
H2O
CH4
CO2
Swain et al, submitted Griffith Tinetti, in
prep
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NIR-MIR emission spectroscopy
MIPS photometry Knutson et al., 2008
HD189733b, day-side
CO2
H2O
IRAC photometry Charbonneau et al., 2008
CH4
Deming et al.
IRS new reduction Swain et al.
IRS spectroscopy Grillmair et al., 2008
NICMOS, Swain et al., 2009
CO2
Swain et al, submitted Griffith Tinetti, in
prep
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NIR emission spectroscopy
HD209458b, day-side
H2O
CH4
CO2
CH4
CO2
Swain, Tinetti, Vasisht, Deroo, Griffith, et al.,
2009
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NIR emission spectroscopy
HD209458b, day-side
Swain, Tinetti, Vasisht, Deroo, Griffith, et al.,
2009
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Exploring the vertical thermal structure

• Thermal
• variations 50
• (Hearty, et al. 2009)

Desert
(AIRS data)
Mid-lat
Polar
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Exploring parameter space T-P
HD209458b, day-side
Swain, Tinetti, Vasisht, Deroo, Griffith, et al.,
2009
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Degeneracy T-P profile, mixing ratios
Swain, Tinetti, Vasisht, Deroo, Griffith, et al.,
2009
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Degeneracy composition T-P profile
Swain, Tinetti, Vasisht, Deroo, Griffith, et al.,
2009
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Comparison HD189-HD209
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Conclusions

• We find water vapour, methane present in all 3
  Hot-Jupiters
• CO2, hazes, CO are also likely to be present
• There is a degeneracy of interpretation mixing
  ratios/thermal profiles.
• More data at higher resolution are desirable to
  break the degeneracy,
• and also better line lists for methane,
  hydrocarbons, H2S, CO2, etc. _at_ 1000-2000K

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Acknowledgments
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(No Transcript)
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Water, BT2, between 800K and 2500K
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Coming soon
High-res. Spectroscopy from ground, Super-Earths
Earth-size planets
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James Webb Space Telescope NASA-ESA (launch
2014)
High-res. Spectroscopy for Hot-Jupiters/Neptunes
Super-Earths Earth-size planets
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SPICA

• Japanese (ISAS/JAXA) proposal for successor
  mission to Spitzer, Akari and Herschel
• Telescope 3.5m, lt5 K
• Herschel 3.5m, 80K
• JWST 6m, 45K
• Core ? 5-200 µm
• ??0.35-14
• Orbit Sun-Earth L2 Halo
• Warm Launch, Cooling in Orbit
• No Cryogen ? 3.2 t
• Long Lifetime
• Launch 2017

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THESIS the mission for combined light

• 2-5 micron, SWIR 5-15 micron, MWIR
• PI Mark Swain

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Acknowledgments
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Back-up
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IRAC transmission band-photometry
Beaulieu, Kipping, Batista, Tinetti, Ribas et
al., submitted
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IRAC transmission band-photometry
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IRAC transmission band-photometry
5.8 micron, a linear drift
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Spectral data measured simultaneously during a
single eclipse event.
Well sampled lightcurve agrees.
Due diligence shows multi-eclipse photometry
uncertainty too large to support the Sing et al.
2009 claim.
Poorly sampled lightcurve disagrees.
Sing et al. 2009
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There is only a way to correct a transit for
spots not having to.

• Primary eclipse depth varies due to star spots.
• HD 189733b has 1.5 V band changes over 11
  days (blue).
• Single visit photometry coverage inadequate for
  eclipse depth measure so visits (red, black)
  combined by adjusting to common scale is
  required 0.01 precision achieved?.
• Uncertainty 0.2 measured by 1.87 vs 1.67 ? µm
  flux flip in addition to uncertain
  variability correction.
• Sing et al. need 0.01 relative visit precision
  for their claim.
• Flux flip shows true measurement uncertainty is
  20 times greater than level need to support
  claim.
• Error bars in Sing et al. 2009 are systematically
  unrealistically small.
• Spectroscopy get data all at once for robust
  differential eclipse depth measurement single
  eclipse avoids uncertainty of combining visits

Fig. 2 Sing et al. 2009
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Carbon Monoxide?
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IRAC Secondary transit photometry
HD189733b, day-side
water CO
Charbonneau et al., 2008 Barman, 2008 Knutson
et al., 2008
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NIR-MIR emission spectroscopy
MIPS photometry Knutson et al., 2008
HD189733b, day-side
CO2
H2O
IRAC photometry Charbonneau et al., 2008
CH4
Deming et al.
IRS new reduction Swain et al.
IRS spectroscopy Grillmair et al., 2008
NICMOS, Swain et al., 2009
CO2
Swain et al, submitted Griffith Tinetti, in
prep
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Hydrogen Sulfide?
PNNL
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S, N, C, O abundance solar
The chemistry of Hot-Jupiters

• Photochemistry
• predicted with Kinetics
• (M.C. Liang private communication)
• Zahnle et al., 2008

S-chain
H2S gt 10-5
Tinetti, Liang, et al., ApjL, 2007
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CxHx, HCN?
PNNL HITRAN GEISA UCL -gt HCN (Tennyson,
Harris) UCL -gt C2H2 (Tennyson)
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MIR emission spectroscopy
Swain, et al. submitted Bouwman et al., in prep
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James Webb Space Telescope performances (MIRI)
Probe the atmospheres of Earth-size planets in
the habitable zone of M-stars
Cavarroc, Cornia, Tinetti, Boccaletti
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Terrestrial Planet Spectra Vary Widely in Solar
System
MIR signatures for terrestrial planets in our
Solar System
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Degeneracy T-P profile, mixing ratios
Swain, Tinetti, Vasisht, Deroo, Griffith, et al.,
2009
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Water, BT2, between 800K and 2500K
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NIR emission spectroscopy NICMOS
HD189733b, day-side
Swain, Vasisht, Tinetti et al., ApJL, 2009
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annulus/Rs2 0.01
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Rplanet2/Rstar2 1