Infrared Transmission Spectra for Extrasolar Giant Planets

Question

1. What are the contributions mentioned in the paper "Infrared transmission spectra for extrasolar giant planets" ?

2. What are the future works in "Infrared transmission spectra for extrasolar giant planets" ?

3. How many planetary atmospheres can contain H2O?

4. What is the effect of CO on the optical depth?

Accepted Answer

Here the authors simulate transmission spectra of these two planets during their primary transit in the MIR, and they present sensitivity studies of the spectra to the changes of atmospheric thermal properties, molecular abundances, and C/O ratios.. The authors find here that the absorption features caused by water vapor and carbon monoxide in a cloud-free atmosphere are deep enough to be observable by the present and future generation of space-based observatories, such as Spitzer Space Telescope and James Webb Space Telescope.. The authors discuss their results in light of the capabilities of these telescopes.

Accepted Answer

The authors have presented here simulations of transmission spectra of two extrasolar giant planets during their transit in front of their parent star.. If water vapor and CO are as abundant as photo- chemical models predict, the authors expect that they can be detected with the Spitzer IRAC, IRS, and MIPS instruments and with future telescopes like JWST.

Accepted Answer

In a solar system like ours, a significant amount of water vapor (H2O) can exist only in planetary atmospheres at orbital distances less than 1 AU.

Accepted Answer

Due to their presence, the atmospheric optical depth might increase, partially masking the absorption features due to atmospheric molecules.

Accepted Answer

if an accuracy of 0.03% is obtainable, future observations may give a first direct estimate of H2O and CO abundances in the upper atmosphere of EGPs and possibly—depending on their mixing ratios—a constraint on CO2, CH4, and C2H2.

Accepted Answer

Carbon monoxide (CO) and methane (CH4), and other photochemical products, such as carbon dioxide (CO2) and acetylene (C2H2), are plausibly present in the atmospheres of EGPs and possibly abundant to be detected.

Accepted Answer

Temperature influences the transmission spectrum by way of its influence on the atmospheric scale height, as discussed by Brown (2001), and on the absorption coefficients.

Accepted Answer

The authors estimate an excess absorption in the IR of up to 0.15% for HD 189733b and up to 0.12% for HD 209458b (C/O ratio ∼ solar), in addition to the nominal 2.85% and 1.6% absorptions measured at shorter wavelengths.

Accepted Answer

Temperature plays a secondary role in the determination of the optical depth: it affects the absorption coefficients and the atmospheric scale heights (see eq. [2] in Ehrenreich et al. 2006).

Accepted Answer

The planet HD 189733b, recently discovered by Bouchy et al. (2005) with mass M ∼p and , orbits an early main-sequence K star at1.15M R ∼ 1.26RJ p J 0.0313 AU.

Accepted Answer

Water vapor has strong absorption lines through all of the selected spectral range in the MIR; the CO signature appears only in a narrower wavelength interval, where the IRAC 4.5 mm bandpass is centered.

Accepted Answer

In this Letter the authors limit their simulations to the cloud-haze–free atmosphere, with the caveat that they might be perturbed by the possible presence (constant or variable) of optically thick particles in the atmosphere above 1 bar pressure.

Accepted Answer

These species have strong absorption bands in the MIR, and more importantly, in spectral regions compatible with present and future space-based observations such as Spitzer or the James Webb Space Telescope (JWST; Gardner et al. 2006).

Accepted Answer

The profiles calculated by Tian etT-P al. (2005) and Yelle (2004) suggest that the trend for the atmospheric temperature is to increase in the exosphere.

Accepted Answer

Their model atmospheres extend to 10 bars, where nonlocal 10 thermodynamic equilibrium (non-LTE) effects might occur (Kutepov et al. 1998).

Accepted Answer

Here the authors focus their interest on both planets HD 209458b and HD 189733b, and the authors model the spectral absorption features in the mid-infrared (MIR) due to the most abundant atmospheric molecules during their primary transit, i.e., when the planet passes in front of the parent star.

Accepted Answer

The authors es-K p 5.5 timate the brightness in the four IRAC bands to be of the order of 1850, 1100, 730, and 400 mJy at 3.6, 4.5, 5.8, and 8 mm, respectively.

Infrared Transmission Spectra for Extrasolar Giant Planets

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Most frequently asked questions

1. What are the contributions mentioned in the paper "Infrared transmission spectra for extrasolar giant planets" ?

2. What are the future works in "Infrared transmission spectra for extrasolar giant planets" ?

3. How many planetary atmospheres can contain H2O?

4. What is the effect of CO on the optical depth?

5. How much accuracy is needed to estimate the chemical abundances of EGPs?

6. What are the abundant photochemical products in the atmosphere of EGPs?

7. What is the effect of temperature on the transmission spectrum of a star?

8. How much absorption is needed for HD 189733b?

9. What is the effect of temperature on the optical depth?

10. What is the planetary orbit of HD 189733b?

11. What is the spectral absorption coefficient of water vapor?

12. What is the purpose of this Letter?

13. What is the spectral absorption of HD 189733b?

14. What is the trend for the temperature of the atmosphere?

15. How many bars of haze do the authors have?

16. What is the spectral absorption of the two planets?

17. How many mJys are in the IRAC bands?

Figures

Citations

The presence of methane in the atmosphere of an extrasolar planet

Water vapour in the atmosphere of a transiting extrasolar planet

Transmission Spectra of Three-Dimensional Hot Jupiter Model Atmospheres

Optimal estimation retrievals of the atmospheric structure and composition of HD 189733b from secondary eclipse spectroscopy

Water vapour in the atmosphere of the habitable-zone eight-Earth-mass planet K2-18 b

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