SPECTROSCOPIC EVIDENCE FOR A TEMPERATURE INVERSION IN THE DAYSIDE ATMOSPHERE OF HOT JUPITER WASP-33b

By Korey Haynes, A. Mandell, N. Madhusudhan, D. Deming, H. Knutson. 2015

135 citations recorded by the source corpus.

We present observations of two occultations of the extrasolar planet WASP-33b using the Wide Field Camera 3 (WFC3) on the Hubble Space Telescope, which allow us to constrain the temperature structure and composition of its dayside atmosphere. WASP-33b is the most highly irradiated hot Jupiter discovered to date, and the only exoplanet known to orbit a δ-Scuti star. We observed in spatial scan mode to decrease instrument systematic effects in the data, and removed fluctuations in the data due to stellar pulsations. The rms for our final, binned spectrum is 1.05 times the photon noise. We compare our final spectrum, along with previously published photometric data, to atmospheric models of WASP-33b spanning a wide range in temperature profiles and chemical compositions. We find that the data require models with an oxygen-rich chemical composition and a temperature profile that increases at high altitude. We find that our measured spectrum displays an excess in the measured flux toward short wavelengths that is best explained as emission from TiO. If confirmed by additional measurements at shorter wavelengths, this planet would become the first hot Jupiter with a thermal inversion that can be definitively attributed to the presence of TiO in its dayside atmosphere.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/dc80b12b0611e61262dd813fd991def9df732886

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In Astronomy and Astrophysics

1. N. Madhusudhan
2. Jon Fortney
3. A. Showman
4. V. Parmentier
5. M. Marley
6. M. Line
7. D. Sing
8. J. D'esert

Citations in the corpus

• CHARACTERIZING TRANSITING EXOPLANET ATMOSPHERES WITH JWST (2015, background): “…by Line et al. (2014a) indicates no strong statistical evidence for inversions in a sample of 9 observed planets, but the very hot Jupiters HAT-P-7b (Christiansen et al. 2010) and WASP-33b (Haynes et al. 2015) do appear to have temperature inversions at the present time (see also Crossfield 2015).”
• 2018 Census of Interstellar, Circumstellar, Extragalactic, Protoplanetary Disk, and Exoplanetary Molecules (2018, unknown): “…[35] Walsh et al. (2016) [36] van Zadelhoff et al. (2001) References: [1] Barman et al. (2011) [2] Barman et al. (2015) [3] Deming et al. (2013) [4] Haynes et al. (2015) [5] Kreidberg et al. (2014) [6] Kreidberg et al. (2015) [7] Lanotte et al. (2014) [8] Lockwood et al. (2014) [9] Madhusudhan et…”
• HD 209458b in new light: evidence of nitrogen chemistry, patchy clouds and sub-solar water (2017, background): “…various aspects of exoplanetary atmospheres, including chemical signatures (Snellen et al. 2010; Deming et al. 2013), temperature profiles (Haynes et al. 2015; Line et al. 2016), circulation patterns (Stevenson et al. 2014), clouds/hazes (Sing et al. 2016), and escape processes…”
• Global Climate and Atmospheric Composition of the Ultra-hot Jupiter WASP-103b from HST and Spitzer Phase Curve Observations (2018, background): “…features, some show emission features, and some are consistent with blackbody models (Madhusudhan et al. 2011; Crossfield et al. 2012; Stevenson et al. 2014a; Haynes et al. 2015; Evans et al. 2016; Beatty et al. 2017a,b; Sheppard et al. 2017; Arcangeli et al. 2018; Mansfield et al. 2018).”
• Chemical enrichment of giant planets and discs due to pebble drift (2017, background): “Nevertheless, observations show that hot Jupiters may have C/O ratios that range from approximately stellar (Kreidberg et al. 2014; Line et al. 2014; Haynes et al. 2015) to C/O & 1 (Madhusudhan et al. 2011; Stevenson et al. 2014)1.”
• ExoMol line lists – XVIII. The high-temperature spectrum of VO (2016, background): “…et al. 2010; Madhusudhan & Seager 2010; Huitson et al. 2012; Spiegel & Burrows 2013; Gibson et al. 2013; Parmentier et al. 2013; Agúndez et al. 2014; Hoeijmakers et al. 2015; Schwarz et al. 2015; Haynes et al. 2015; Wakeford & Sing 2015) about a possible temperature c© 2002 The Authors Table 1.”
• DETECTION OF H2O AND EVIDENCE FOR TiO/VO IN AN ULTRA-HOT EXOPLANET ATMOSPHERE (2016, background): “Of these, TiO/VO absorption has been ruled out for WASP-12b (Teq ∼ 2600 K; Sing et al. 2013) and WASP-19b (Teq ∼ 2100 K; Huitson et al. 2013), while evidence for TiO emission has been reported for WASP-33b (Teq ∼ 2700 K; Haynes et al. 2015).”
• Exoplanetary Atmospheres: Key Insights, Challenges, and Prospects (2019, methodology): “In addition, signs of TiO, VO, and AlO have also been reported using HST and/or large ground-based facilities (102, 76, 232, 273).”
• TRANSITIONS IN THE CLOUD COMPOSITION OF HOT JUPITERS (2016, background): “Despite several attempts to search for TiO and VO in hot Jupiters atmospheres (Désert et al. 2009; Sing et al. 2013) weak evidence of its presence has been found only in the hottest known planet (Haynes et al. 2015).”
• H− Opacity and Water Dissociation in the Dayside Atmosphere of the Very Hot Gas Giant WASP-18b (2018, background): “Our results for WASP-18 b have consequences for the new family of very hot gas giants, where extrapolation from cooler planets can be misleading (WASP-33 b: Haynes et al. 2015, WASP-103 b: Cartier et al. 2017, WASP-18 b: Sheppard et al. 2017, WASP-121 b: Evans et al. 2017).”
• NO THERMAL INVERSION AND A SOLAR WATER ABUNDANCE FOR THE HOT JUPITER HD 209458B FROM HST/WFC3 SPECTROSCOPY (2016, background): “The recent possible detection of a thermal inversion for WASP-33b (Haynes et al. 2015) is not inconsistent with this statement as this planet exhibits an average dayside brightness temperature of 3000 K, which means it is in a very different physical and chemical regime as more typical hot Jupiters…”
• From thermal dissociation to condensation in the atmospheres of ultra hot Jupiters: WASP-121b in context (2018, background): “Among them are targets with existing atmospheric characterization such as WASP-12b, WASP-33b, WASP-103b, WASP-121b, Kepler13Ab, KELT-1b, WASP-18b, and HAT-P-7b.”