<p>You wouldn't see the supercritical water: Typical solar-like molecular gas mixtures become optically thick at around 0.1-1 bars, so that's where the emission is going to come from, i.e. where most lines are going to be formed.</p>
<p>When you see water at this pressure you don't know how much sits below, i.e. you can't really determine the total amount of water in the atmosphere, or the total atmospheric mass.</p>

CC BY-SA 4.0
2023-04-18T17:27:52.923Z
right, forgot that we cannot see rock composition either of exoplants, just the part of gaseous form surrounding such exoplanets.  So, hyperpressurized chemical component should not be viewable (yet) by spectral analysis.  Accepting this as an answer.
John Greene
CC BY-SA 4.0
2023-04-18T11:12:52.910Z
2023-04-18T11:12:52.910Z
AtmosphericPrisonEscape
<p>Much spectrum analysis on many chemical compounds are mapped and categorized at Earth atmosphere (1000 millibar) or thereabouts.</p>
<p>But many celestial objects are of greater ranges of surface pressure.</p>
<p>And many chemical compounds reach supercriticality at higher pressure.</p>
<p>One of those chemical compound is water molecule.  Water molecule exhibit a different ro-vibrational in the diffraction spectral analysis at deeper pressure.</p>
<p>Are we compensating and broadening our their search parameters for super-criticality of such chemical compounds when doing this passive spectral analysis of and for their search of exoplanets?</p>
<p>Was reading this paper on “Mid-IR spectroscopy of supercritical water: from diluted gas to dense fluid”.</p>
<p><a href="https://bpb-us-w2.wpmucdn.com/voices.uchicago.edu/dist/2/2305/files/2019/11/Hestand-et-al.-2019-Mid-IR-spectroscopy-of-supercritical-water-From-d.pdf" rel="nofollow noreferrer">https://bpb-us-w2.wpmucdn.com/voices.uchicago.edu/dist/2/2305/files/2019/11/Hestand-et-al.-2019-Mid-IR-spectroscopy-of-supercritical-water-From-d.pdf</a></p>

CC BY-SA 4.0
2023-04-17T10:59:43.200Z
I believe that the shown differences discussed in the linked paper are rather minute compared to the available accuracy of exoplanet spectra.
planetmaker
CC BY-SA 4.0
2023-04-17T11:11:41.000Z
“shown differences” or “more diffused” (fuzzier)?
John Greene
CC BY-SA 4.0
2023-05-03T19:54:52.000Z
More details. https://webbtelescope.org/contents/articles/what-would-earths-atmosphere-look-like-from-the-webb-telescope
John Greene
CC BY-SA 4.0
2024-03-25T14:52:15.383Z
More on biomarkers on exoplanets. https://www.quantamagazine.org/doubts-grow-about-the-biosignature-approach-to-alien-hunting-20240319/
John Greene
<exoplanet><spectra><water><exotic-matter>
Are we searching for supercriticality of exoplanet water via passive spectral analysis?
John Greene
# Are we searching for supercriticality of exoplanet water via passive spectral analysis?

(Asked by: username_0 on 2023-04-17)

Much spectrum analysis on many chemical compounds are mapped and categorized at Earth atmosphere (1000 millibar) or thereabouts.

But many celestial objects are of greater ranges of surface pressure.

And many chemical compounds reach supercriticality at higher pressure.

One of those chemical compound is water molecule. Water molecule exhibit a different ro-vibrational in the diffraction spectral analysis at deeper pressure.

Are we compensating and broadening our their search parameters for super-criticality of such chemical compounds when doing this passive spectral analysis of and for their search of exoplanets?

Was reading this paper on “Mid-IR spectroscopy of supercritical water: from diluted gas to dense fluid”.

<https://bpb-us-w2.wpmucdn.com/voices.uchicago.edu/dist/2/2305/files/2019/11/Hestand-et-al.-2019-Mid-IR-spectroscopy-of-supercritical-water-From-d.pdf>

**Tags:** exoplanet, spectra, water, exotic-matter

> **Comments:**
> **username_1**: I believe that the shown differences discussed in the linked paper are rather minute compared to the available accuracy of exoplanet spectra.  
> **username_0**: “shown differences” or “more diffused” (fuzzier)?  
> **username_0**: More details. https://webbtelescope.org/contents/articles/what-would-earths-atmosphere-look-like-from-the-webb-telescope  
> **username_0**: More on biomarkers on exoplanets. https://www.quantamagazine.org/doubts-grow-about-the-biosignature-approach-to-alien-hunting-20240319/  

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## 1 answers

### Answer by username_2 on 2023-04-18. Score: 4 | Accepted answer

You wouldn't see the supercritical water: Typical solar-like molecular gas mixtures become optically thick at around 0.1-1 bars, so that's where the emission is going to come from, i.e. where most lines are going to be formed.

When you see water at this pressure you don't know how much sits below, i.e. you can't really determine the total amount of water in the atmosphere, or the total atmospheric mass.

> **Comments:**
> **username_0**: right, forgot that we cannot see rock composition either of exoplants, just the part of gaseous form surrounding such exoplanets.  So, hyperpressurized chemical component should not be viewable (yet) by spectral analysis.  Accepting this as an answer.  

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