INFRARED TRANSMISSION SPECTROSCOPY OF THE EXOPLANETS HD 209458b AND XO-1b USING THE WIDE FIELD CAMERA-3 ON THE HUBBLE SPACE TELESCOPE

By D. Deming, A. Wilkins, P. McCullough, Adam Burrows, Jon Fortney, E. Agol, I. Dobbs-Dixon, N. Madhusudhan, N. Crouzet, J. D'esert and 11 more. 2013

340 citations recorded by the source corpus.

Exoplanetary transmission spectroscopy in the near-infrared using the Hubble Space Telescope (HST) NICMOS is currently ambiguous because different observational groups claim different results from the same data, depending on their analysis methodologies. Spatial scanning with HST/WFC3 provides an opportunity to resolve this ambiguity. We here report WFC3 spectroscopy of the giant planets HD 209458b and XO-1b in transit, using spatial scanning mode for maximum photon-collecting efficiency. We introduce an analysis technique that derives the exoplanetary transmission spectrum without the necessity of explicitly decorrelating instrumental effects, and achieves nearly photon-limited precision even at the high flux levels collected in spatial scan mode. Our errors are within 6% (XO-1) and 26% (HD 209458b) of the photon-limit at a resolving power of λ/δλ ∼ 70, and are better than 0.01% per spectral channel. Both planets exhibit water absorption of approximately 200 ppm at the water peak near 1.38 μm. Our result for XO-1b contradicts the much larger absorption derived from NICMOS spectroscopy. The weak water absorption we measure for HD 209458b is reminiscent of the weakness of sodium absorption in the first transmission spectroscopy of an exoplanet atmosphere by Charbonneau et al. Model atmospheres having uniformly distributed extra opacity of 0.012 cm2 g−1 account approximately for both our water measurement and the sodium absorption. Our results for HD 209458b support the picture advocated by Pont et al. in which weak molecular absorptions are superposed on a transmission spectrum that is dominated by continuous opacity due to haze and/or dust. However, the extra opacity needed for HD 209458b is grayer than for HD 189733b, with a weaker Rayleigh component.

Subfields: Aerospace Engineering, Astronomy and Astrophysics

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The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Aerospace Engineering

1. N. Madhusudhan
2. D. Sing
3. D. Deming
4. J. D'esert
5. Jon Fortney
6. Sara Seager
7. A. Vidal-Madjar
8. G. Henry

In Astronomy and Astrophysics

1. N. Madhusudhan
2. Jon Fortney
3. A. Showman
4. D. Sing
5. M. Line
6. D. Deming
7. J. D'esert
8. Sara Seager

Citations in the corpus

• HUBBLE SPACE TELESCOPE NEAR-IR TRANSMISSION SPECTROSCOPY OF THE SUPER-EARTH HD 97658B (2014, methodology): “Spectral Template Fitting Method In this approach we utilized the spectral template method first presented in Deming et al. (2013), which we describe in detail in Knutson et al. (2014) and summarize here.”
• SPECTROSCOPIC EVIDENCE FOR A TEMPERATURE INVERSION IN THE DAYSIDE ATMOSPHERE OF HOT JUPITER WASP-33b (2015, methodology): “On the contrary, the non-inversion model fit shown in Figure 5 has a C-rich composition, as discussed below, consistent with the findings of Deming et al. (2013), and has a significantly poorer fit compared to the O-rich inversion model as discussed above.”
• A DETECTION OF WATER IN THE TRANSMISSION SPECTRUM OF THE HOT JUPITER WASP-12b AND IMPLICATIONS FOR ITS ATMOSPHERIC COMPOSITION (2015, background): “The amplitude of these features has often been smaller than predicted for transiting planets, due to the presence of clouds or haze and shallower thermal profiles (e.g. Fortney et al. 2006; Char- bonneau et al. 2002; Deming et al. 2013).”
• 2018 Census of Interstellar, Circumstellar, Extragalactic, Protoplanetary Disk, and Exoplanetary Molecules (2018, neutral): “…[34] Thi et al. (2011) [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.…”
• NO THERMAL INVERSION AND A SOLAR WATER ABUNDANCE FOR THE HOT JUPITER HD 209458B FROM HST/WFC3 SPECTROSCOPY (2016, methodology): “…observations of transiting exoplanets are rapidly transforming our knowledge of planetary atmospheres (Berta et al. 2012; Swain et al. 2012; Deming et al. 2013; Huitson et al. 2013; Kreidberg et al. 2014ab,15; Stevenson et al. 2014c; McCullough et al. 2014; Knutson et al. 2014; Fraine et…”
• HOW TO DISTINGUISH BETWEEN CLOUDY MINI-NEPTUNES AND WATER/VOLATILE-DOMINATED SUPER-EARTHS (2013, methodology): “In a numerical retrieval study, we show for GJ 1214b that an unambiguous distinction between a cloudy H2-dominated atmosphere and cloud-free H2O atmosphere will be possible if the uncertainties in the spectral transit depth measurements can be reduced by a factor of ∼ 3 compared to the published HST”
• Hubble Space Telescope hot Jupiter transmission spectral survey: a detection of Na and strong optical absorption in HAT-P-1b (2013, background): “HAT-P-1b is only the second case (after HD 209458b) in the atmosphere of which signatures from both sodium and water are conclusively detected with transmission spectroscopy (Charbonneau et al. 2002; Sing et al. 2012; Deming et al. 2013).”
• H2O abundances and cloud properties in ten hot giant exoplanets (2018, methodology): “E-mail: ap817@ast.cam.ac.uk † E-mail: nmadhu@ast.cam.ac.uk clouds/hazes (e.g., Deming et al. 2013) or due to inherently low H2O abundances (e.g., Madhusudhan et al. 2014a) Sing et al. (2016) interpreted the observed atmospheric spectra using empirical metrics based on chemical equilibrium…”
• HST PanCET Program: A Cloudy Atmosphere for the Promising JWST Target WASP-101b (2017, methodology): “Out of the previously well studied hot Jupiters (e.g., Deming et al. 2013; Kreidberg et al. 2014; Sing et al. 2016) WASP-101b is most similar to WASP-31b.”
• A NEW APPROACH TO ANALYZING HST SPATIAL SCANS: THE TRANSMISSION SPECTRUM OF HD 209458 b (2015, methodology): “Horizontal shifts are important as they displace the spectrum on the detector and also introduce additional systematics to the spectral light-curves, such as undersampling (Deming et al. 2013; Wilkins et al. 2014).”
• THE INFLUENCE OF NONUNIFORM CLOUD COVER ON TRANSIT TRANSMISSION SPECTRA (2015, background): “For simplicity we include only water as the gaseous absorber as it has been the only molecule robustly detected over the WFC3 bandpass (e.g., Deming et al. 2013; Kreidberg et al. 2014; 2015).”