The Changing Face of the Extrasolar Giant Planet HD 209458b

Cho, James Y-K.; Menou, Kristen; Hansen, Bradley M. S.; Seager, Sara

doi:10.1086/375016

Cited by 197 publications

(291 citation statements)

References 26 publications

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“…As the stellar flux is always concentrated on the same hemisphere of the planet, strong atmospheric circulation should take place between the dayside and the nightside (see e.g. Cho et al 2003Cho et al , 2008Showman 2005, 2006;Iro et al 2005;Rauscher et al 2007Rauscher et al , 2008aRauscher et al , 2008bThrastarson and Cho 2010). This circulation pattern can be studied by monitoring the planetary phase curve (see Sect.…”

Section: Transit Spectroscopy: What Can It Tell Us?mentioning

confidence: 99%

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Spectroscopy of planetary atmospheres in our Galaxy

Tinetti

Encrenaz

Coustenis

2013

Astron Astrophys Rev

130

111

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About 20 years after the discovery of the first extrasolar planet, the number of planets known has grown by three orders of magnitude, and continues to increase at neck breaking pace. For most of these planets we have little information, except for the fact that they exist and possess an address in our Galaxy. For about one third of them, we know how much they weigh, their size and their orbital parameters. For less than 20, we start to have some clues about their atmospheric temperature and composition. How do we make progress from here?We are still far from the completion of a hypothetical Hertzsprung-Russell diagram for planets comparable to what we have for stars, and today we do not even know whether such classification will ever be possible or even meaningful for planetary objects. But one thing is clear: planetary parameters such as mass, radius and temperature alone do not explain the diversity revealed by current observations. The chemical composition of these planets is needed to trace back their formation history and evolution, as happened for the planets in our Solar System. As in situ measurements are and will remain off-limits for exoplanets, to study their chemical composition we will have to rely on remote sensing spectroscopic observations of their gaseous envelopes.

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Section: Transit Spectroscopy: What Can It Tell Us?mentioning

confidence: 99%

“…Cho et al 2003Cho et al , 2008Showman et al 2009;Showman and Polvani 2011;Rauscher et al 2008aRauscher et al , 2008bThrastarson and Cho 2010).…”

Section: Planet Phase-variationsunclassified

Spectroscopy of planetary atmospheres in our Galaxy

Tinetti

Encrenaz

Coustenis

2013

Astron Astrophys Rev

130

111

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“…(v) How does the large range of insolation, planetary spin, orbital elements and compositions in these diverse planetary systems affect the atmospheric dynamics? This has direct consequences for our ability to predict the evolution of these planets [41,42,130,134,147]. (vi) Are planets around low mass, active stars able to keep their atmospheres?…”

Section: Exoplanets Todaymentioning

confidence: 99%

“…Once formed, the storms move off poleward toward the nightside, carrying with them heat and chemical species, which are observable. The storms then dissipate to repeat the cycle after a few planet rotations [41,42]. Storms of such size and dynamism are characteristic of synchronized planets, much more so than unsynchronized ones.…”

Section: Spatial and Temporal Variability: Weather Climate And Exo-cmentioning

confidence: 99%

The EChO science case

et al. 2015

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The discovery of almost two thousand exoplanets has revealed an unexpectedly diverse planet population. We see gas giants in few-day orbits, whole multi-planet systems within the orbit of Mercury, and new populations of planets with masses between that of the Earth and Neptune-all unknown in the Solar System. Observations to date have shown that our Solar System is certainly not representative of the general population of planets in our Milky Way. The key science questions that urgently need addressing are therefore: What are exoplanets made of? Why are planets as they are? How do planetary systems work and what causes the exceptional diversity observed as compared to the Solar System? The EChO (Exoplanet Characterisation Observatory) space mission was conceived to take up the challenge to explain this diversity in terms of formation, evolution, internal structure and planet and atmospheric composition. This requires in-depth spectroscopic knowledge of the atmospheres of a large and well-defined planet sample for which precise physical, chemical and dynamical information can be obtained. In order to fulfil this ambitious scientific program, EChO was designed as a dedicated survey mission for transit and eclipse spectroscopy capable of observing a large, diverse and well-defined planet sample within its 4-year mission lifetime. The transit and eclipse spectroscopy method, whereby the signal from the star and planet are differentiated using knowledge of the planetary ephemerides, allows us to measure atmospheric signals from the planet at levels of at least 10 −4 relative to the star. This can only be achieved in conjunction with a carefully designed stable payload and satellite platform. It is also necessary to provide broad instantaneous wavelength coverage to detect as many molecular species as possible, to probe the thermal structure of the planetary atmospheres and to correct for the contaminating effects of the stellar photosphere. This requires wavelength coverage of at least 0.55 to 11 μm with a goal of covering from 0.4 to 16 μm. Only modest spectral resolving power is needed, with R~300 for wavelengths less than 5 μm and R~30 for wavelengths greater than this. spectroscopy technique means that no spatial resolution is required. A telescope collecting area of about 1 m 2 is sufficiently large to achieve the necessary spectro-photometric precision: for the Phase A study a 1.13 m 2 telescope, diffraction limited at 3 μm has been adopted. Placing the satellite at L2 provides a cold and stable thermal environment as well as a large field of regard to allow efficient time-critical observation of targets randomly distributed over the sky. EChO has been conceived to achieve a single goal: exoplanet spectroscopy. The spectral coverage and signal-to-noise to be achieved by EChO, thanks to its high stability and dedicated design, would be a game changer by allowing atmospheric composition to be measured with unparalleled exactness: at least a factor 10 more precise and a factor 10 to 1000 more accurate tha...

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“…Atmospheric circulation models (e.g., Showman and Guillot, 2002; Cho e t aE., 2003; Cooper and Showman, 2005) have not yet been coupled with radiative transfer models. In this absence, the atmospheric circulation has been parameterized by a parameter f: a value of f = 1 implies that the incident stellar radiation is emitted into 4.rr steradians (meaning the heat is evenly redistributed throughout the planet's atmosphere), while f = 2 implies that the incident stellar radiation is emitted into only 2n steradians (i.e., only the day side absorbs and emits the radiation, and there is no transport to the night side).…”

Section: Model Atmospheresmentioning

confidence: 99%