HST Transmission Spectral Survey: observations, analysis and results

Transcription

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

2 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

3 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 = 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 Wasp-6b Wasp-39b Wakeford et al Hat-P-1b Nikolov et al Sing et al Wasp-31b Ballester et al. in prep. Wasp-17b Huitson et al Wasp-19b Sing et al Wasp-12b N. Nikolov Period Rplanet (days) (Jup) Mplanet (Jup) ( Teff is estimated equilibrium temperature) Teff (K) g Irradiation Vmag (m/s2) (ergs/s/cm2) E E E E E E E E H (km) From Super-Earths to Brown Dwarfs: Who s Who?

4 Relative altitude in scale heights z( )/H STIS G430L STIS G750L WFC3 IRAC 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) Wavelength (µm)

5 HST STIS G430L G750L Photon counts ( 10 4 ) corrected fringing Wavelength (Å)

6 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

7 HST STIS Normalised raw raw flux flux Ballester et al. in prep Normalised Normalised flux flux O-C O-C ( 10 ( 10-4 ) -4 ) G430L G430L G430L G430L G750L G750L G750L G430L G430L G750L Time Time since since mid-transit (hr) (hr) Time since mid-transit (hr)

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

9 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. W et al u D2 Burrows H1 W H X J H2 S D1 4 8 N C 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 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. T(8 µm) = 1580+/-150 K WASP-South is hosted by the South African Astronomical ObWASP-12 b low albedo; efficient T redistrib.1.65 servatory and we are grateful for their support and assistance. based on Funding for WASP comes Models from consortium universities and from the UK s Science and Technology Facilities Council Burrows et al u Parent star: The Astrophysical Journal, 779:128 (18pp), 2013 December 20 type: F6, V = 11.6 REFERENCES 1.46 Sp 1.38 Solar, no TiO Solar & Isoth., TAgol, = 2500 K J., Sari, R., & Clarkson, W. 2005, MNRAS,Solar & Isoth, T = 2000 K E., Steffen, 359, Na 0 Solar in the atmosphere Bakos, G. A., et al.(3) 2007, 1.44 ApJ, 656,I 552and H2 WASP-12 b carbon WASP H O, 10x &b Isoth. + haze 1.40 U C3 d RJupiter ~ 6 % Jupiter density Wood et al. 2011, Zhou et al Mandel et al Transit Depth (%) Radius/RJup T4 W Three facts for WASP-17b times that of HD b, for both of which successful The ratio of projected areas of planetary atmosphere to stellar The Astrophysical Journal, 779:128 (18pp), 2013 December disk of WASP-17b is times that of HD b and Vol. 709 Anderson et al. 2010, (2) Retrograde orbit Transit Depth (%) 2 Triaud et al Bayliss et al. al Transit Depth (%) Baranne, A., et al. 1996, A&AS, 119, Bodenheimer, P., Lin, D. N. C., & Mardling, R. A. 2001, ApJ, 548, based onplanets. Figure 7. Mass radius distribution of the 62 Models known transiting extrasolar Bo hm-vitense, E. 2004, AJ, 128, 2435 The best-fitting values for the three WASP-17b according 1.48 Madhusudhan 2012 Burrows al u models areetdepicted Burrows, A., Budaj, J., & Hubeny, I. 2008, ApJ, 678, to the key given in Table 4. Other WASP planets are filled, red circles; non Burrows, A., Hubeny, I., Budaj, J., & Hubbard, W. B. 2007, ApJ, 661, 502 WASP planets are open, black circles; Jupiter, Saturn, Neptune, and Uranus are Charbonneau, D., Brown, T. M., Latham, D. W., & Mayor, M. 2000, ApJ, 529, filled, gray diamonds, labeled with1.46 the planets initials. For clarity, error bars are L displayed only for WASP-17b. Some planets discovered by CoRoT, HAT, TrES, Charbonneau, D., Brown, 1.55 T. M., Noyes, R. W., & Gilliland, R. L. 2002, ApJ, WASP, and XO are labeled with the project initial and the system number (e.g., 1.44 Solar & Isoth., T = 2500 K 568, 377 WASP-17b = W17). HD b is labeled D1 and HD b is labeled 1.36 Charbonneau, D., et al. 2005, ApJ, 626, H2O, 10x carbon D2. The labeled, dashed lines depict a range of density contours in Jovian units. Chatterjee, S., Ford, E. B.,1.50 Matsumura, S., & Rasio, F. A. 2008, ApJ, 686, Data are taken from this work and Cochran, W. D., et al. 2004, ApJ, 611, L133 Models based on (A color version of this figure is available in the online journal.) Collier Cameron, A., et al. 2006, MNRAS, 373, 799 Madhusudhan 2012 Collier Cameron, A., et al , MNRAS, 380, D Angelo, G., Lubow, S. H., & Bate, M. R. 2006, ApJ, 652, 1698 ets in retrograde orbits. Therefore, we suggest that WASP-17b Desert, J.-M., Lecavelier des Etangs, A., Hebrard, G., Sing, D. K., Ehrenreich, supports the hypothesis that1.38 some short-orbit, giant planets are D., Ferlet, R., & Vidal-Madjar, A. 2009, ApJ, 699, 478 Solar, no TiO produced by a combination of scattering, the Kozai mechanism, Fabrycky, D. C., & Winn, 1.40 J. N. 2009, ApJ, 696, 1230 O-Rich (C/O = 0.5) O-Rich (C/O = 0.5) Solar & Isoth., T = 2500 K Solar & Isoth, T = 2000 K 1.44 Ford, E. B. 2006, ApJ, 642, 505 and tidal circularization. The observation of the RM effect for 1.36 C-Rich (C/O = 1.5) C-Rich H O, 10x carbon 0.1 Ford, E. B., & Rasio, F. A. 2008, ApJ, 686, 621 Solar & Isoth. + (C/O haze = 1.5) more short-orbit planets is required to measure the size 2of the 1.90 Fortney, J. J., Lodders, K.,1.65 Marley, M. S., & Freedman, R. S. 2008, ApJ, 678, contribution Models 1.2 based 1.3 on For planet planet or star planet scattering to have influenced Fortney, J. J., Marley, M. S., & Barnes, J. W. 2007, ApJ, 659, 1661 Wavelength (µ m) Gaudi, B. S., & Winn, J. N. 2007, ApJ, 655, 550 WASP-17b s orbit in the past, one Madhusudhan or more stellar or planetary Gillon, M. 2009, arxiv: companions must Figure have been present in the system. Sensitive 18. Transit depths for each of the 19 binsm.,for each target, based ons.,the framework of Burrows etwho? al. (top N. Nikolov From Super-Earths to Brown Dwarfs: Who s Gillon, Pont, F., Moutou, C., with Bouchy,models F., Courbin, F., Sohy, & Magain, imaging could probe for a stellar companion, and further RV 1.38 June 29th - July IAP, Paris b 2006, 459, 249 models from Burrows et al. provide a goodp.fit fora&a, WASP-17 b and a reasonable fit for WASP-12 b,3rd but2015, for 1.40 WASP-19 measurements are necessary to search for stellar or planetary 1.55 Gillon, M., et al. 2009a, A&A, 496, 259 O-Rich (C/O = 0.5) Mass/MJup

10 WASP-17b Ballester et al. in prep.

11 Aligned orbit Anderson et al 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

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

13 (1) Prograde orbit Gillon et al 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) (2) Scattering in the atmosphere Fortney et al. (2010), T = 1500 K Fortney et al. (2010), T = 1000 K Scattering Planet-to-star radius ratio (Rpl/R ) Jordan et al Wavelength (Å)

14 Na I K I WASP-6b Nikolov et al (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

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

16 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.