Extrasolar Planets: Questions & Answers

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Discussion Overview

The discussion revolves around the observation and analysis of extrasolar planets, specifically focusing on infrared observations at different wavelengths, the implications of flux measurements on atmospheric understanding, and the significance of detecting water and carbon monoxide in relation to the habitability of these planets.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • Some participants question the differences in observations made at 4 microns versus 24 microns, suggesting that the elements detected and inferences about atmospheric composition vary with wavelength.
  • One participant proposes that measuring flux decrement during a planet's transit can help deduce its temperature and the potential existence of atmospheric components.
  • Another participant asserts that the presence of carbon monoxide (CO) and water does not automatically indicate habitability, emphasizing that water alone does not imply a planet is inhabited.
  • A participant mentions the complexity of calculating a planet's temperature, indicating that a model of the atmosphere and the star's energy flux must be considered, rather than relying on a simple formula.
  • There is a reference to Wien's law as a method for estimating the temperature of stars, but it is noted that this approach is not directly applicable to planets without additional considerations.

Areas of Agreement / Disagreement

Participants express uncertainty regarding the specifics of infrared observations and the implications of detected atmospheric components. There is no consensus on the best methods for calculating the temperature of extrasolar planets or the implications of finding water and CO.

Contextual Notes

Limitations include the need for specific atmospheric models and the dependence on various assumptions regarding distance from the star and energy flux, which remain unresolved in the discussion.

kmoukiss
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Hi everyone !

I am doing a report of some papers on extrasolar planets and I would like to clarify some points!
1) What is the difference between oberving in the IR at 4microns or 24microns ? what do you get in difference in observation ?

2)how can a measure of flux decrement can affect our understanding of the atmosphere of the planet ?

and finally 3) if water and CO are being revealed, how does this affect the survival prospects of extrasolar planets ?

I hope you will be able to help me!
Thanks to all !
 
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1) I'm not too sure about this.
2) Well, if you measure the flux decrement in infrared when the planet passes behind its star, it's possible to deduce how much infrared is coming from the planet itself. From this, you can calculate the planet's temperature and determine what can or cannot exist in the atmosphere.
3) I think this is fairly obvious. CO is toxic; water is vital for just about all life on Earth.
 
kmoukiss said:
Hi everyone !

I am doing a report of some papers on extrasolar planets and I would like to clarify some points!
1) What is the difference between oberving in the IR at 4microns or 24microns ? what do you get in difference in observation ?

2)how can a measure of flux decrement can affect our understanding of the atmosphere of the planet ?

and finally 3) if water and CO are being revealed, how does this affect the survival prospects of extrasolar planets ?

I hope you will be able to help me!
Thanks to all !

Hi
I wonder if you can help me, I want the formula or the mathematical equation that calculate the temperature of Extrasolar plantes.

thanks
 
kmoukiss said:
1) What is the difference between oberving in the IR at 4microns or 24microns ? what do you get in difference in observation ?

The difference between observing in 4 or 24 microns is what elements are you detecting. Or what you can infer about the composition of the atmosphere. You build a synthetic spectra varying the composition of the possible atmosphere and than you compare with the observed spectra. Actually it is easier to use photometry instead of spectroscopy, but anyway, it is basically this. And also maybe your equipment has a better resolution in one of these IR regions.
kmoukiss said:
and finally 3) if water and CO are being revealed, how does this affect the survival prospects of extrasolar planets ?

It is important to note that water alone does not imply that the planet is habitated.

rasha astro said:
Hi
I wonder if you can help me, I want the formula or the mathematical equation that calculate the temperature of Extrasolar plantes.
thanks

I think it is not as simple as it could be. But one way to have an idea about the temperature of a STAR is using the Wien's law. But you can do this, because roughly you can consider a star as a blackbody.
[tex] {\nu}_{max} \approx 5.879 \times 10^{10} (Hz/T).T[/tex]

For a planet I am afraid it is completely incorrect to use this formula. You must have a model about the atmosphere of the planet, also you must consider the distance from the star, and the star's flux of energy. There is not a specific formula where you can calculate the temperature of the planet. You must consider it's composition.
You can take a look in this paper http://arxiv.org/abs/0910.1347
 

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