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FormingWorlds / JANUS

1-D prescribed atmosphere model of planetary atmospheres that makes use of the SOCRATES radiative transfer code.
https://proteus-code.readthedocs.io/
Apache License 2.0
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Height integration #12

Open nichollsh opened 3 months ago

nichollsh commented 3 months ago

In some cases the height integration blows up.

This is particularly bad when the atmosphere has a low MMW and a high temperature, so integrating down to pressures ~1 Pa leads to scale heights ~1e9 metres. This effectively represents a state where the atmosphere is unbound.

We know the height integration works fine, because it usually gets reasonable values. I've also tested it for Jupiter-like cases (pure H2, cold) and it gets scale heights ~50 km. It also compares well against RFM retrievals.

Since the cell heights are only needed for plotting (at the moment) we could simply not calculate them.

timlichtenberg commented 3 months ago

Alternatively, you just set a simple check for when this happens (and log the PROTEUS step), and then prevent plotting. I say this because I find this very useful, and – indeed – at the moment it is just optics, but it in principle computes the planet total / transit size.

nichollsh commented 3 months ago

Makes sense. It would probably be best if this flag is included in JANUS directly, since that's where the heights are calculated. I'll make this change once the cloud stuff is merged. It will then require a small change to PROTEUS to log when this is caught.

nichollsh commented 1 month ago

Note that this issue is also found to occur in modelling by Maxime Maurice in this work.

No realistic transit radii for H-rich reduced small planets could be obtained because the assumption of hydrostatic equilibrium breaks down in these conditions of surface pressure, temperature, and gravity.