THE FLAT TRANSMISSION SPECTRUM OF THE SUPER-EARTH GJ1214b FROM WIDE FIELD CAMERA 3 ON THE HUBBLE SPACE TELESCOPE

By Z. K. Berta, D. Charbonneau, J. D'esert, Eliza Miller-Ricci Kempton, P. McCullough, C. Burke, Jon Fortney, J. Irwin, P. Nutzman, Derek Homeier. 2011

302 citations recorded by the source corpus.

Capitalizing on the observational advantage offered by its tiny M dwarf host, we present Hubble Space Telescope/Wide Field Camera 3 (WFC3) grism measurements of the transmission spectrum of the super-Earth exoplanet GJ1214b. These are the first published WFC3 observations of a transiting exoplanet atmosphere. After correcting for a ramp-like instrumental systematic, we achieve nearly photon-limited precision in these observations, finding the transmission spectrum of GJ1214b to be flat between 1.1 and 1.7 μm. Inconsistent with a cloud-free solar composition atmosphere at 8.2σ, the measured achromatic transit depth most likely implies a large mean molecular weight for GJ1214b's outer envelope. A dense atmosphere rules out bulk compositions for GJ1214b that explain its large radius by the presence of a very low density gas layer surrounding the planet. High-altitude clouds can alternatively explain the flat transmission spectrum, but they would need to be optically thick up to 10 mbar or consist of particles with a range of sizes approaching 1 μm in diameter.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/95990e6347fd810e6782ffa707186d766c46fbaa

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In Astronomy and Astrophysics

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

In Instrumentation

1. Jon Fortney
2. N. Madhusudhan
3. D. Charbonneau
4. A. Showman
5. M. Line
6. H. Knutson
7. D. Sing
8. D. Deming

Citations in the corpus

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• HST hot-Jupiter transmission spectral survey: detection of potassium in WASP-31b along with a cloud deck and Rayleigh scattering (2014, methodology): “Previous analyses of other HST transit observations (Berta et al. 2012; Line et al. 2013; Sing et al. 2013; Nikolov et al. 2014b; Knutson et al. 2014b) have found this to be a reasonable approximation.”
• C/O RATIO AS A DIMENSION FOR CHARACTERIZING EXOPLANETARY ATMOSPHERES (2012, background): “…et al. 2008, Desert et al. 2009, Redfield et al. 2008, Madhusudhan & Seager 2009, Sing et al. 2011, Bean et al. 2010, Crossfield et al. 2012, Berta et al. 2012), thermal phase curves (Knutson et al. 2007, 2012; Showman et al. 2009; Cowan et al. 2012), and direct imaging (e.g. Marois et al.…”
• The Detectability and Characterization of the TRAPPIST-1 Exoplanet Atmospheres with JWST (2019, background): “…of hot gaseous exoplanets has demonstrated how the presence of clouds and hazes can diminish sensitivity to molecular absorption features (e.g., Berta et al. 2012; Ehrenreich et al. 2014; Knutson et al. 2014; Kreidberg et al. 2014; Nikolov et al. 2015; Sing et al. 2016), but we know a priori…”
• A PRECISE WATER ABUNDANCE MEASUREMENT FOR THE HOT JUPITER WASP-43b (2014, methodology): “The dominant systematic is an HST orbit-long ramp (Berta et al. 2012; Deming et al. 2013; Kreidberg et al. 2014; Wilkins et al. 2014), which we fit with an exponential function (using the model-ramp parameterization from Kreidberg et al. 2014).”
• Hubble Space Telescope hot Jupiter transmission spectral survey: a detection of Na and strong optical absorption in HAT-P-1b (2013, methodology): “Systematics correction was also performed following the divide out of transit (divide-oot) method described in Berta et al. (2012), where a template correction is constructed using the data from the out of transit orbits.”
• HUBBLE SPACE TELESCOPE NEAR-IR TRANSMISSION SPECTROSCOPY OF THE SUPER-EARTH HD 97658B (2014, background): “GJ 1214b is currently the only one of these three systems with a well-characterized transmission spectrum, which is flat and featureless across a broad range of wavelengths (e.g., Bean et al. 2010, 2011; Désert et al. 2011; Berta et al. 2012; Kreidberg et al. 2014).”
• QUANTITATIVELY ASSESSING THE ROLE OF CLOUDS IN THE TRANSMISSION SPECTRUM OF GJ 1214b (2013, methodology): “Berta et al. (2012) obtained a near-IR spectrum using Wide Field Camera 3 on the Hubble Space Telescopeand found a transmission spectrum consistent with a featureless specturm. de Mooij et al. (2012) observed the transit of GJ 1214b in the optical bandsg, r, i, I and z and near-infrared bandsKs and…”
• WATER VAPOR IN THE SPECTRUM OF THE EXTRASOLAR PLANET HD 189733b. I. THE TRANSIT (2014, background): “…outset to maintain independence, no computer code was shared between the two efforts, but both analysts had read or written the relevant literature, particularly descriptions by McCullough et al. (201) Berta et al. (2012), Deming et al. (2013), Kreidberg et al. (2014), and Knutson et al. (2014).”
• A SYSTEMATIC RETRIEVAL ANALYSIS OF SECONDARY ECLIPSE SPECTRA. I. A COMPARISON OF ATMOSPHERIC RETRIEVAL TECHNIQUES (2013, background): “Upon inspecting Figure 7 we find that the WFC3 data combined with the ground based photometric points trims the 2σ tail but does little to improve the 1σ uncertainties.”
• ATMOSPHERIC RETRIEVAL FOR SUPER-EARTHS: UNIQUELY CONSTRAINING THE ATMOSPHERIC COMPOSITION WITH TRANSMISSION SPECTROSCOPY (2012, background): “Recent observational efforts (e.g., Bean et al. 2010; Croll et al. 2011; Berta et al. 2012) suggest that the continuous improvements in observational techniques will enable us to extend the field of atmospheric characterization to the regime of super-Earths (exoplanets with mass between 1 and 10…”
• A DETECTION OF WATER IN THE TRANSMISSION SPECTRUM OF THE HOT JUPITER WASP-12b AND IMPLICATIONS FOR ITS ATMOSPHERIC COMPOSITION (2015, methodology): “Transit light curve observations with HST/WFC3 have several well-documented systematic trends in flux with time, including visit-long slopes and orbit-long exponential ramps (Berta et al. 2012; Swain et al. 2013; Kreidberg et al. 2014b; Stevenson et al. 2014a).”
• The Complete Transmission Spectrum of WASP-39b with a Precise Water Constraint (2017, methodology): “Observational data analysis is a non-trivial exercise and there are an array of techniques being applied to reduce data (e.g. Berta et al. 2012; Gibson et al. 2012; Deming et al. 2013; Wakeford et al. 2016).”
• The minimum-mass extrasolar nebula: in situ formation of close-in super-Earths (2012, background): “The MEarth Project currently sets exposure times to detect planets with R = 2R⊕ at 3σ confidence (Berta et al. 2012).”