HST Transmission Spectral Survey: observations, analysis and results

Image credit: David A. Aguilar (CfA) Image credit: ESA HST Transmission Spectral Survey: observations, analysis and results Nikolay Nikolov and the HST Team

Collaborators: Image credits: NASA, ESA, and G. Bacon (STScI) D. K. Sing (PI) F. Pont T. Kataria T. M. Evans H. R. Wakeford N. Nikolov A. S. Burrows J. J. Fortney G. E. Ballester C. M. Huitson J.-M. Desert P. A. Wilson S. Aigrain D. Deming N. P. Gibson G. W. Henry H. Knutson A. Lecavelier des Etangs A. P. Showman A. Vidal-Madjar K. Zahnle Princeton University UC Santa Cruz University of Arizona University of Colorado University of Colorado CNRS, Paris University of Oxford University of Maryland ESO Tennessee SU Caltech CNRS, Paris University of Arizona CNRS, Paris NASA

Image credit: ESA Spectra based on the models (red/purple) of Fortne al. (2010)PI andd.k. ZahnleSing) et al. (2009) and the STIS Large HST program (C) (126 etorbits, Hat-P-12b S/N levels achievable in this program (blac for 8 planets with TeqWFC3 = 1000-3000 K histogram - STIS & WFC3 simulated spectra wi final co-added noise). (A) The hotter planets lik Na Published results for:strong Ti K H O Wasp-17b are expected to have 2 STIS: optical G430L & G750L (0.3-1μm ) WASP-12b, signatures. WASP-19b, (B) Alternatively, these planets cou WFC3: near-ir G141 HAT-P-1b, WASP-31b, WASP-6b; but have stratosphere-causing HS. (C) Th Spitzer/IRAC 3.6 μm and 4.5 μm lack TiO cooler planets HAT-P-12b are expected hav two like more in preparation; Rayleigh strong Na and K lines, and intermediate cases lik (i) compare atmospheric properties; Wasp-6b are possible (D). The targets span a wid (ii) detect strong absorbers (e.g. Na, K, TiO, hazes, clouds, etc.); range of effective temperature from 1000 to 3000 K Image credit: David A. Aguilar (CfA) Aims: (iii) probe atmospheric diversities. Table 1. Hot-Jupiter Target List Target Hat-P-12b Nikolov et al. 2015 Wasp-6b Wasp-39b Wakeford et al. 2013 Hat-P-1b Nikolov et al. 2014 Sing et al. 2015 Wasp-31b Ballester et al. in prep. Wasp-17b Huitson et al. 2013 Wasp-19b Sing et al. 2013 Wasp-12b N. Nikolov Period Rplanet (days) (Jup) 3.21 0.96 3.36 1.22 4.05 1.27 4.46 1.20 3.4 1.54 3.74 1.74 2.15 1.15 1.09 1.79 Mplanet (Jup) 0.21 0.50 0.28 0.53 0.48 0.49 1.31 1.41 ( Teff is estimated equilibrium temperature) Teff (K) 1080 1340 1360 1500 1800 1860 2319 2800 11 g Irradiation Vmag (m/s2) (ergs/s/cm2) 5.7 8.3 4.3 9.1 5.02 4.0 16.6 11.0 2.2E+08 5.2E+08 5.00E+08 7.3E+08 1.50E+09 1.9E+09 4.10E+09 1.0E+10 12.8 11.9 12.1 10.4 11.7 11.6 12.3 11.69 H (km) 680 580 1140 580 1280 1670 501 930 From Super-Earths to Brown Dwarfs: Who s Who?

Relative altitude in scale heights z( )/H 15 10 5 0 5 STIS G430L STIS G750L WFC3 IRAC 3.6 4.5 10 3 Rayleigh H2 Rayleigh Na I K I Hazy atmosphere H2O H 2O H 2O CO Cloud-free atmosphere Hot Jupiter models from Fortney et al. (2010).3.4.5.6.7.8.9 1 2 3 4 5 Wavelength (µm)

HST STIS 3.5 3.0 G430L G750L Photon counts ( 10 4 ) 2.5 2.0 1.5 1.0 corrected 0.5 0.0 fringing 3000 4000 5000 6000 7000 8000 9000 10000 Wavelength (Å)

Our pipeline Assume orbital period (Porb) from literature 2 3 Fit for all transit parameters and systematics (at fixed limb darkening and Porb) 1 HST STIS and WFC3 spectra + Spitzer IRAC photometry 2 HST STIS white light curves + Spitzer IRAC 3.6 & 4.5 µm 4 Marginalize over ~50 systematics models (Gibson et al. 2014) System parameters (a/rst, i, Rp/Rst, T0, Porb) 5 Update orbital ephemeris (new + literature T0s) 6 Fix system parameters and limb darkening; fit for Rp/Rst, and systematics; TRANSMISSION SPECTRUM 7

HST STIS Normalised raw raw flux flux 1.010 1.010 1.005 1.005 0.990 0.990 0.980 0.990 0.990 0.980 Ballester et al. in prep. 1.010 1.010 0.990 1.005 1.005 0.990 0.980 0.980 0.975 0.990 0.990 0.975 Normalised Normalised flux flux 0.990 0.990 0.990 0.980 0.980 0.980 10 5 55 0 0-5 -10-5 O-C O-C ( 10 ( 10-4 ) -4 ) G430L G430L G430L G430L G750L 0.980 G750L G750L G430L G430L G750L 10 5 0-5 -10-3 -2-2 -1 0 0 1 22 3-2 0 2 0.990-3 -2-2-1 0 0 1 2 2 3-3 -3-2 -2-2-1-1 00 0 1 1 2 22 3 3-2 0 2-2 0 2 Time Time since since mid-transit (hr) (hr) Time since mid-transit (hr) 0.990 0.990 0.990 0.990 0.980 0.980 0.980 10 0.980 10 5 5 5 5 0 0 0-5 0-5 -5-10 -10-5

Spitzer IRAC Ballester et al. in prep. 3.6 µm 4.5 µm

ANDERSON ET AL. (1) Bloated radius 1.8 W12 attempts at measuring atmospheric signatures have been made A&A 524, A25 (2010) WASP-12 b (e.g., Charbonneau et al. 2002; WASP-17 b al-3.7 Orbital Period ~ Desert et al. 2009). Thus, 1.65 though WASP-17 ismp fainter~ and1.6 has a larger stellar,radius, the Models based on M Rp ~2 Saturn W15 system is a good prospect for transmission spectroscopy. W4 1.48 et al. 2008 u D2 Burrows 1.60 1.4 H1 W6 0.06 0.13 1 H12 0.25 0.8 0.5 1 0.6 X3 1.46 0.03 1.44 J H2 S 2 1.42 D1 4 8 N C7 16 32 ρj We acknowledge a thorough and constructive report from the 2.05 anonymous referee. TheT(4.5 WASP consortium comprises the Uniµm) = 1880+/-50 KDecember 20 1.55 St. Andrews, The Astrophysical Journal, 779:128 (18pp), 2013 versities of Keele, Leicester, the Queen s University Belfast, the Open University and the Isaac Newton Group. 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WASP-17b Ballester et al. in prep.

Aligned orbit Anderson et al. 2010 Quick facts for WASP-31b Orbital Period ~ 3.4 d Mp ~ 0.5 MJupiter Rp = 1.5 RJupiter 13 % Jupiter density Teq = 1600 K, H~1200 km Parent star Sp type: F6, V = 11.7

WASP-31b Sing et al. 2015 (i) sub-solar Na/K ratio; (ii) H2O dominated atmosphere ruled out at 9σ; (iii) two-particle regimes for <0.52 and 0.52µm

(1) Prograde orbit Gillon et al. 2009 Two facts for WASP-6b Orbital Period ~ 3.4 d Mp ~ 0.5 MJupiter Rp ~ 1.2 RJupiter Teq = 1145 K Parent star Sp type: G8, [Fe/H]=-0.2 V = 11.9 Planet radius (RJ) 1.35 1.3 1.25 1.2 (2) Scattering in the atmosphere Fortney et al. (2010), T = 1500 K Fortney et al. (2010), T = 1000 K Scattering 0.155 0.15 0.145 0.14 0.135 Planet-to-star radius ratio (Rpl/R ) Jordan et al. 2013 1.15 5000 6000 7000 8000 Wavelength (Å)

Na I K I WASP-6b Nikolov et al. 2015 (i) Cloud-free atmosphere ruled out with high confidence; (ii) Rayleigh and Mie scattering models highly preferred with MgSiO3, KCl, Mg2SiO4 and Na2S condensates; STIS G430L STIS G750L IRAC

WASP-6b Nikolov et al. (2015) H2O H 2O H2O CO WASP-17b Ballester et al. (in prep.)

Conclusions: (1) WASP-17b, -31b and -6b show evidence for cloud-free, cloudy and hazy atmosphere, i.e. an emerging diversity of exoplanet atmospheres; (2) We find a significant variation in both the Na and K frequency and the Na/K abundance ratio across the targets; (3) Cloudy and hazy atmospheres can provide important atmospheric constraints, i.g. particle sizes, temperatures, etc.; (4) More planets must be studied in transmission to establish correlations between atmospheric and planetary physical properties, e.g. atmospheric type and planet evolutionary history.