Author Topic: Planet's Atmosphere  (Read 1440 times)

Planet's Atmosphere
« on: 06/25/2016 04:34 PM »
How are scientists able to figure out what a planet's atmosphere is? I've heard of atmospheric probes and exoplanet's light showing a certain gas.  But I don't really understand how it's done.

Offline Bynaus

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Re: Planet's Atmosphere
« Reply #1 on: 06/25/2016 04:52 PM »
Light of the exoplanets' star passing through the planets atmosphere on its way to Earth interacts with the molecules in the atmosphere. Certain wavelengths of the starlight are absorbed (depending on the molecule doing the absorbing), leading to a deficit of these wavelengths in the spectrum of the star. So absorbtion lines in a spectrum allow the identification of gases in the planets atmosphere.

Of course, the planet or its atmosphere are far too small to be resolved, so one has to subtract the starlight when the planet is not in transit (passing in front of the star as viewed from Earth) from the starlight when the planet is in transit.
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Re: Planet's Atmosphere
« Reply #2 on: 06/25/2016 05:16 PM »
OK, Great!  And how about planet's in our solar system?

Offline Hungry4info3

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Re: Planet's Atmosphere
« Reply #3 on: 06/25/2016 07:16 PM »
The planets in our solar system, being closer, reflect enough like for us to do direct spectroscopy on them. We look at their light and look at what spectral features are missing.

Offline Robotbeat

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Re: Planet's Atmosphere
« Reply #4 on: 06/25/2016 09:25 PM »
It's actually still very nice to see how their atmospheres are filtering starlight. Stellar eclipsing spectroscopy is useful for both planets in our solar system and exoplanets.
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Re: Planet's Atmosphere
« Reply #5 on: 06/27/2016 02:38 AM »
Could you please recommend some good books or videos on the subject ?

Offline Bynaus

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Re: Planet's Atmosphere
« Reply #6 on: 06/27/2016 07:39 AM »
There is an introductory/review article by Sara Seager here: http://arxiv.org/abs/1005.4037 Its almost 6 years old though, but it will give you an understanding of the basics.
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Offline hop

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Re: Planet's Atmosphere
« Reply #7 on: 06/27/2016 07:53 AM »
Could you please recommend some good books or videos on the subject ?
"SETI talks" on the SETI institute youtube channel is a good place to look
https://www.youtube.com/channel/UCzQdkHKOTVT_chwgDcau4sg

Tags: planet atmosphere