Detection of an Extrasolar Planet Atmosphere

By D. Charbonneau, T. Brown, R. W. Noyes, R. Gilliland. 2001

1,131 citations recorded by the source corpus.

We report high-precision spectrophotometric observations of four planetary transits of HD 209458, in the region of the sodium resonance doublet at 589.3 nm. We find that the photometric dimming during transit in a bandpass centered on the sodium feature is deeper by (2.32 ± 0.57) × 10-4 relative to simultaneous observations of the transit in adjacent bands. We interpret this additional dimming as absorption from sodium in the planetary atmosphere, as recently predicted from several theoretical modeling efforts. Our model for a cloudless planetary atmosphere with a solar abundance of sodium in atomic form predicts more sodium absorption than we observe. There are several possibilities that may account for this reduced amplitude, including reaction of atomic sodium into molecular gases and/or condensates, photoionization of sodium by the stellar flux, a low primordial abundance of sodium, and the presence of clouds high in the atmosphere.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/2c0e5e991715170e80948db70b3e4e2fdbd57b64

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In Astronomy and Astrophysics

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

Citations in the corpus

• Rayleigh scattering in the transit spectrum of HD 189733b (2008, background): “Transiting extrasolar planets, like HD189733b offer unique opportunities to scrutinize their atmospheric content (e.g., Charbonneau et al. 2002, Vidal-Madjar et al. 2003).”
• Possible Solutions to the Radius Anomalies of Transiting Giant Planets (2006, background): “We note that the detection by Charbonneau et al. (2002) of sodium in the atmosphere of HD 209458b is best fit by the presence of hazes (Fortney et al. 2003) or some additional grayish absorber.”
• A Unique Solution of Planet and Star Parameters from an Extrasolar Planet Transit Light Curve (2002, background): “…of transiting planets are possible, such as atmosphere transmission spectroscopy (note the first extrasolar planet atmosphere detection by Charbonneau et al. 2002), search for moons and rings (Brown et al. 2001), and detection of oblateness and the corresponding constraint on rotation…”
• The Influence of Atmospheric Dynamics on the Infrared Spectra and Light Curves of Hot Jupiters (2006, background): “Showman & Guillot (2002) and Iro et al. (2005) pointed out that the transit detection of weak neutral atomic Na absorption by Charbonneau et al. (2002) could be explained if a large fraction of Na was tied up in this condensate.”
• Design Considerations for a Ground-Based Transit Search for Habitable Planets Orbiting M Dwarfs (2007, background): “Already, transmission spectroscopy has probed the atmospheric chemistries of HD 209458b (Charbonneau et al. 2002; Vidal-Madjar et al. 2003; Barman 2007) and HD 189733b (Tinetti et al. 2007), while infrared monitoring during secondary eclipse has led to the detection of broadband thermal emission…”
• Using Stellar Limb-Darkening to Refine the Properties of HD 209458b (2006, background): “…results of several follow-up observations of the planetary atmosphere (e.g., Charbonneau et al. 2006a), notably through transmission spectroscopy (Charbonneau et al. 2002; Deming et al. 2005a), upper limits on reflected light (Rowe et al. 2006), and the study of the planetary thermal emission…”
• HD 209458b in new light: evidence of nitrogen chemistry, patchy clouds and sub-solar water (2017, background): “Serving as the prototypical target for atmospheric characterisation, it was the first exoplanet observed to contain Na (Charbonneau et al. 2002).”
• A FRAMEWORK FOR CHARACTERIZING THE ATMOSPHERES OF LOW-MASS LOW-DENSITY TRANSITING PLANETS (2013, background): “Since the first observations of light transmitted (Charbonneau et al. 2002) and emitted (Charbonneau et al. 2005; Deming et al. 2005) by hot Jupiters, the realm of exoplanet characterization has expanded into a larger sample size of hot Jupiters (Seager & Deming 2010) as well as into smaller…”
• CHARACTERIZING K2 PLANET DISCOVERIES: A SUPER-EARTH TRANSITING THE BRIGHT K DWARF HIP 116454 (2014, background): “…exoplanets around bright, nearby stars is important because measuring the precise masses and radii of transiting planets allows for characterization of their interior structures and atmospheres (Charbonneau et al. 2002; Rogers 2014; Knutson et al. 2014; Teske et al. 2013; Kreidberg et al. 2014).”
• Temperature–pressure profile of the hot Jupiter HD 189733b from HST sodium observations: detection of upper atmospheric heating (2012, methodology): “Theory predicts the presence of strong Na I D lines in hot Jupiter atmospheres (Seager & Sasselov 2000; Brown 2001), and observations have so far agreed, with atomic sodium detected in hot Jupiters (Charbonneau et al. 2002; Redfield et al. 2008; Snellen et al. 2008; Sing et al. 2008a; Wood et al. 20”
• Internal structure of massive terrestrial planets (2005, background): “There is very little known about these new planets, sin e no dire t observations have been made yet, however in at least one ase the transit observations led to the dete tion of the planet's atmosphere (Charbonneau et al. 2002, Vidal-Madjar et al. 2003).”
• Hubble Space Telescope hot Jupiter transmission spectral survey: a detection of Na and strong optical absorption in HAT-P-1b (2013, methodology): “We therefore, select bands of varying width, each centred on the sodium doublet (λNa = 5893 Å), aiming similar to Charbonneau et al. (2002) to span “narrow”, “medium” and “wide” wavelength regions.”
• Rejecting Astrophysical False Positives from the TrES Transiting Planet Survey: The Example of GSC 03885–00829 (2006, background): “Examples of detailed follow– up observations include the measurement of several chemical abundances in the atmosphere of HD209458b (Charbonneau et al. 2002; Vidal-Madjar et al. 2003) and the first direct detections of emitted planetary radiation (Charbonneau et al. 2005; Deming et al. 2005).”
• An extended upper atmosphere around the extrasolar planet HD209458b (2003, background): “, only the dense lower atmosphere of HD209458b has been observed, through the detection of neutral sodium absorptio”
• OBSERVATIONS OF MASS LOSS FROM THE TRANSITING EXOPLANET HD 209458b (2010, background): “HD 209458b is the first transiting planet for which atmospheric absorption was observed in the resonance lines of Na I (Charbonneau et al. 2002) and subsequently in lines of H I, C II, O I, and others.”