Editing Openai/6946e998-79f0-8007-9a65-19828450838d (section)

==== Take the conservative habitable zone (Kopparapu et al.-style): ====
* Inner edge: runaway greenhouse (well outside “recent Venus”)
* Outer edge: maximum greenhouse (well inside “early Mars”)

This already:
* Excludes orbits like modern Venus that are almost certainly over-irradiated even for Earth-like atmospheres.
* Excludes orbits like modern Mars that are too weakly irradiated even with optimistic CO₂.

Effect on η⊕:
* For Sun-like stars, going from “optimistic” HZ to “conservative” HZ tends to cut η⊕ roughly in half (very roughly; exact factor depends on the paper). You go from “maybe ~0.5–1 per star” to more like “~0.2–0.5 per star” as a typical ballpark.

So step (1) alone significantly reduces Venus-like and very Mars-like flux cases.