Theory of Extrasolar Giant Planet Transits

By W. Hubbard, Jon Fortney, Jonathan I. Lunine, Adam Burrows, D. Sudarsky, Philip A. Pinto. 2001

185 citations recorded by the source corpus.

We present a synthesis of physical effects influencing the observed light curve of an extrasolar giant planet (EGP) transiting its host star. The synthesis includes a treatment of Rayleigh scattering, cloud scattering, refraction, and molecular absorption of starlight in the EGP atmosphere. Of these effects, molecular absorption dominates in determining the transit-derived radius R for planetary orbital radii less than a few AU. Using a generic model for the atmosphere of EGP HD 209458b, we perform a fit to the best available transit light-curve data and infer that this planet has a radius at a pressure of 1 bar, R1, equal to 94,430 km, with an uncertainty of ~500 km arising from plausible uncertainties in the atmospheric temperature profile. We predict that R will be a function of wavelength of observation, with a robust prediction of at least ±1% variations at infrared wavelengths where H2O opacity in the high EGP atmosphere dominates.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/a89ef927a300ce8820a104e63674f56d46894fe5

How researchers see this paper

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

In Astronomy and Astrophysics

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

In Instrumentation

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

Citations in the corpus

• UNDERSTANDING THE MASS–RADIUS RELATION FOR SUB-NEPTUNES: RADIUS AS A PROXY FOR COMPOSITION (2013, methodology): “We define a planet’s radius at 20 mbar, appropriate for the slant viewing geometry in optical transits (Hubbard et al. 2001).”
• The effect of condensates on the characterization of transiting planet atmospheres with transmission spectroscopy (2005, methodology): “The studies of Hubbard et al. (2001) and Fortney et al. (2003) showed that the pressures probed by transit observations are sensitive function of wavelength.”
• A time-dependent radiative model of HD 209458b (2004, methodology): “However, the sodium absorption seen in the data is lower than predicted by existing models by approximately a factor three (Hubbard et al. 2001; Brown 2001).”
• HST hot-Jupiter transmission spectral survey: detection of potassium in WASP-31b along with a cloud deck and Rayleigh scattering (2014, background): “The possible presence of such condensation clouds was considered early on (Seager & Sasselov 2000; Hubbard et al. 2001).”
• A FRAMEWORK FOR CHARACTERIZING THE ATMOSPHERES OF LOW-MASS LOW-DENSITY TRANSITING PLANETS (2013, methodology): “The code we use to model transmission spectra is fully described in Hubbard et al. (2001), Fortney et al. (2010), and Shabram et al. (2011).”
• On the radiative equilibrium of irradiated planetary atmospheres (2010, background): “It corresponds instead to the level at which optical rays that are grazing, at the terminator, have an optical depth close to unity (Hubbard et al. 2001).”
• Using Stellar Limb-Darkening to Refine the Properties of HD 209458b (2006, methodology): “Based on model transmission spectra for HD 209458b (Seager & Sasselov 2000; Brown 2001; Hubbard et al. 2001), there are only a few metal absorption lines predicted in most of our bandpasses, and the only absorption bands are from water absorption and are located in the longest wavelength bandpasses…”
• QUANTITATIVELY ASSESSING THE ROLE OF CLOUDS IN THE TRANSMISSION SPECTRUM OF GJ 1214b (2013, background): “The depth of features in the transmission spectrum scales asNH ×2HRp/R∗, where NH (the number of scale heights probed) is set by the opacities involved (∼ 1− 10), H is the atmospheric scale height, Rp is the planetary radius, andR∗ is the stellar radius (Seager & Sasselov 2000; Hubbard et al. 2001).”
• The prevalence of dust on the exoplanet HD 189733b from Hubble and Spitzer observations (2012, background): “In the notation of Hubbard et al. (2001), a “Greenhouse factor” γ can be defined as γ = κs/κl where κ are the flux-weighted opacities and s and l denote the shortwave and longwave opacities. γ >1 corresponds to inverted temperature profiles.”
• CAN TiO EXPLAIN THERMAL INVERSIONS IN THE UPPER ATMOSPHERES OF IRRADIATED GIANT PLANETS? (2009, background): “Furthermore, their atmospheres may be probed during both primary eclipse (Seager & Sasselov 2000; Hubbard et al. 2001; Brown 2001) and secondary eclipse (Sudarsky et al. 2000, 2003; Rauscher et al. 2007; Burrows et al. 2008; Fortney et al. 2008).”
• Planetary Radii across Five Orders of Magnitude in Mass and Stellar Insolation: Application to Transits (2006, background): “The corresponding atmospheric pressure can vary across many orders of magnitude, depending on the wavelength (Hubbard et al. 2001; Fortney et al. 2003).”
• A Unified Theory for the Atmospheres of the Hot and Very Hot Jupiters: Two Classes of Irradiated Atmospheres (2007, background): “If the opacity on the limb is everywhere larger in the optical this would lead to weaker, narrower Na absorption peak than expected by the first-generation models (Seager & Sasselov 2000; Brown 2001; Hubbard et al. 2001).”
• KEPLER PLANETS: A TALE OF EVAPORATION (2013, background): “For the same reason, we have ignored the difference between the above radius and the radius a planet exhibits at transit (Hubbard et al. 2001).”
• Detection of an Extrasolar Planet Atmosphere (2001, methodology): “The secondary science goal was to pursue the prediction by Seager & Sasselov (2000) (and, later, Brown 2001; Hubbard et al. 2001) of a strong spectroscopic feature at 589.3 nm due to absorption from sodium in the planetary atmosphere.”
• Analytic Light Curves for Planetary Transit Searches (2002, background): “For treatment of subtler effects during planetary transitsee Seager et al. (2000); Seager & Sasselov (2000); Hubbard et al. (2001); Hui & Seager (2002).”
• Evolutionary models for cool brown dwarfs and extrasolar giant planets. The case of HD 209458 (2003, background): “The picture could be different in the case of irradiated atmospheres, where extension effects due to the large heating of the upper layers may not be negligible (Seager & Sasselov 2000; Hubbard et al. 2001).”
• Theoretical Spectral Models of the Planet HD 209458b with a Thermal Inversion and Water Emission Bands (2007, background): “Moreover, with precision photometry, the wavelength-dependence of the transit radii can provide a measure of a planet’s atmospheric composition (Burrows et al. 2000; Hubbard et al. 2001; Fortney et al. 2003; Barman 2007).”
• DISEQUILIBRIUM CARBON, OXYGEN, AND NITROGEN CHEMISTRY IN THE ATMOSPHERES OF HD 189733b AND HD 209458b (2011, background): “…for inferring properties of both the planet and its host star (e.g., Charbonneau et al. 2000, 2002, 2005; Henry et al. 2000; Seager & Sasselov 2000; Brown 2001; Brown et al. 2001; Burrows et al. 2001; Hubbard et al. 2001; Deming et al. 2005b; Knutson et al. 2007, 2009; Madhusudhan & Seager 2009).”