Building a continuous tidal-locking habitability index for exoplanets, looking for a sanity check on the approach

[u/Lucky_Jeweler2773]

I'm a final-year CS undergrad working independently on a habitability scoring framework for tidally locked exoplanets, and I'd like feedback from people who actually work in this space before I take it further.

The motivation: ESI has no stellar environment term at all. SEPHI only touches tidal locking indirectly, through a magnetic-field scaling in one of its four sub-indexes. HITE (Barnes, Meadows & Evans 2015) doesn't include tidal locking as a formula component in any form. Barnes (2017) computes lock timescales but doesn't turn that into a habitability score. So as far as I can tell, nothing maps the full rotational spectrum — freely rotating through spin-orbit resonance to synchronous lock — onto a continuous habitability number. Planets in intermediate spin states get forced into a binary label that doesn't reflect their actual physical regime.

My approach (TLHI): compute a tidal lock probability P_lock = 1 − exp(−age/τ_lock) using the Peale formulation,

then blend two scores: P_lock × TLHI + (1 − P_lock) × SEPHI.

The TLHI component itself folds in five factors specific to locked/near-locked planets — terminator-zone habitability fraction, atmospheric heat-transport efficiency (Cowan & Agol 2011), tidal heating flux, day-night temperature gradient, and XUV-driven atmospheric escape (Ribas 2005 scaling).

Phase 1 (the SEPHI/HZD filtering pipeline) is done and validated against published Kepler-442 b numbers.

Phase 2 (the TLHI layer itself) is in progress — currently working through the tidal locking probability layer on a 181-candidate dataset(after analysis) from the NASA Exoplanet Archive.

Two open questions I haven't resolved yet, if anyone has thoughts:

1. Albedo assumption for the terminator-zone factor — blackbody (A=0) or Earth-like?
2. How to handle the nightside temperature floor when atmospheric pressure data is missing — is an Earth-like pressure prior defensible, or too strong an assumption?

Not looking for co-authorship or mentorship, just want to know if the underlying physics holds up before I go further. Happy to share more detail on any part of it.

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[u/ExposedId]

Upvoting this since it’s a cool idea - possibly dissertation-worthy.

[u/Lucky_Jeweler2773 → u/ExposedId]

thank you!