<i>Theory of Planetary Atmospheres: An Introduction to Their Physics and Chemistry</i>

Chamberlain, Joseph W.; Hunten, D. M.; Andersen, Per H.

doi:10.1063/1.2811644

Cited by 125 publications

(160 citation statements)

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“…To develop an intuition of the nature of exoplanet transmission spectra, we work with an analytical approximation of the transmission of light through the planet's limb [43]. The extinction coefficient, κ e , is assumed to equal that at the impact radius, i.e.…”

Section: Primary Transit Measurements (A) Approximate Eclipse Depthmentioning

confidence: 99%

Disentangling degenerate solutions from primary transit and secondary eclipse spectroscopy of exoplanets

Griffith

2014

Phil. Trans. R. Soc. A.

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Infrared transmission and emission spectroscopy of exoplanets, recorded from primary transit and secondary eclipse measurements, indicate the presence of the most abundant carbon and oxygen molecular species (H 2 O, CH 4 , CO and CO 2 ) in a few exoplanets. However, efforts to constrain the molecular abundances to within several orders of magnitude are thwarted by the broad range of degenerate solutions that fit the data. Here, we explore, with radiative transfer models and analytical approximations, the nature of the degenerate solution sets resulting from the sparse measurements of ‘hot Jupiter’ exoplanets. As demonstrated with simple analytical expressions, primary transit measurements probe roughly four atmospheric scale heights at each wavelength band. Derived mixing ratios from these data are highly sensitive to errors in the radius of the planet at a reference pressure. For example, an uncertainty of 1% in the radius of a 1000 K and H 2 -based exoplanet with Jupiter's radius and mass causes an uncertainty of a factor of approximately 100–10 000 in the derived gas mixing ratios. The degree of sensitivity depends on how the line strength increases with the optical depth (i.e. the curve of growth) and the atmospheric scale height. Temperature degeneracies in the solutions of the primary transit data, which manifest their effects through the scale height and absorption coefficients, are smaller. We argue that these challenges can be partially surmounted by a combination of selected wavelength sampling of optical and infrared measurements and, when possible, the joint analysis of transit and secondary eclipse data of exoplanets. However, additional work is needed to constrain other effects, such as those owing to planetary clouds and star spots. Given the current range of open questions in the field, both observations and theory, there is a need for detailed measurements with space-based large mirror platforms (e.g. James web space telescope) and smaller broad survey telescopes as well as ground-based efforts.

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Section: Primary Transit Measurements (A) Approximate Eclipse Depthmentioning

confidence: 99%

Disentangling degenerate solutions from primary transit and secondary eclipse spectroscopy of exoplanets

Griffith

2014

Phil. Trans. R. Soc. A.

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“…The neutral atmospheric temperature T O is chosen to be higher than the temperature of the upper ionosphere and exosphere of Earth, ∼700−1100 K (Schunk & Nagy 2000), or the exosphere of Venus, ∼200−1000 K (Chamberlain & Hunten 1987) since we are considering a planet at a distance of only r = 0.2 AU from a Sun-like star where more energy is available to heat the upper atmosphere. With this atmospheric profile, we justify the existence of a dayside ionospheric production rate that, using standard methods, takes the form of a Chapman profile given by…”

Section: Ionospheric Parametersmentioning

confidence: 99%

“…Johansson et al 2009;Vidal-Madjar et al 2003, 2004Lammer et al 2004;Chamberlain & Hunten 1987); 3) the possibility of detectable stellar-wind-powered low-frequency emissions from cEGPs similar to that from the magnetized planets in the solar system but enhanced by the stronger stellar wind (see e.g. Griessmeier et al 2007a,b;Lazio et al 2004;Farrell et al 1999;Zarka et al 2001); and 4) a range of orbital distances with quasiparallel interaction, i.e.…”

Section: Introductionmentioning

confidence: 99%

Interplanetary magnetic field orientation and the magnetospheres of close-in exoplanets

Johansson

Joachim

Motschmann

2010

A&A

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The abundance of exoplanets with orbits smaller than that of Mercury most likely implies that there are exoplanets exposed to a quasiparallel stellar-wind magnetic field. Many of the generic features of stellar-wind interaction depend on the existence of a nonzero perpendicular interplanetary magnetic field component. However, for closer orbits the perpendicular component becomes smaller and smaller. The resulting quasiparallel interplanetary magnetic field may imply new types of magnetospheres and interactions not seen in the solar system. We simulate the Venus-like interaction between a supersonic stellar wind and an Earth-sized, unmagnetized terrestrial planet with ionosphere, orbiting a Sun-like star at 0.2 AU. The importance of a quasiparallel stellar-wind interaction is then studied by comparing three simulation runs with different angles between stellar wind direction and interplanetary magnetic field. The plasma simulation code is a hybrid code, representing ions as particles and electrons as a massless, charge-neutralizing adiabatic fluid. Apart from being able to observe generic features of supersonic stellar-wind interaction we observe the following changes and trends when reducing the angle between stellar wind and interplanetary magnetic field 1) that a large part of the bow shock is replaced by an unstable quasiparallel bow shock; 2) weakening magnetic draping and pile-up; 3) the creation of a second, flanking current sheet due to the need for the interplanetary magnetic field lines to connect to almost antiparallel draped field lines; 4) stellar wind reaching deeper into the dayside ionosphere; and 5) a decreasing ionospheric mass loss. The speed of the last two trends seems to accelerate at low angles.

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“…4 with three simplifying assumptions (Chamberlain and Hunten 1987), each of which is poor for the extended atmospheres of Pluto and Triton. First, for a plane parallel atmosphere, the optical depth is assumed to be inversely proportional to the cosine of the emission angle (τ ν ∝ 1/µ).…”

Section: Integration Over Altitude Wavelength and Emission Anglementioning

confidence: 99%

Upper Limits on Gaseous CO at Pluto and Triton from High-Resolution Near-IR Spectroscopy

Young

Cook

Yelle

et al. 2001

Icarus

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Theory of Planetary Atmospheres: An Introduction to Their Physics and Chemistry

Cited by 125 publications

References 0 publications

Disentangling degenerate solutions from primary transit and secondary eclipse spectroscopy of exoplanets

Disentangling degenerate solutions from primary transit and secondary eclipse spectroscopy of exoplanets

Interplanetary magnetic field orientation and the magnetospheres of close-in exoplanets

Upper Limits on Gaseous CO at Pluto and Triton from High-Resolution Near-IR Spectroscopy

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