Source: https://guthlabs.ai/docs/instruments/habitable-zone-distance-rough/implementation/

instrument implementation / implementation-contract

# Habitable-Zone Distance (rough) implementation

A source-bound implementation contract for Habitable-Zone Distance (rough); deployment and executable qualification remain separate.

Status: **VERIFIED_CLEAN**Lifecycle: **implementation-contract**

## Binding contract

This record describes what an executable surface must bind and validate. It does not claim that a public calculator, package, or production route is deployed.

**Record owner**: Guth Instruments

**Lifecycle**: verified-clean

**Evidence ID**: t7-006

**Effect**: Computation or source lookup only

## Input and validation requirements

A negative luminosity produces negative square-root arguments and therefore an undefined real HZ distance. The instrument must validate luminosity as nonnegative and reject the input explicitly.

## Required corrections

No binding erratum is attached to this unique-name record. Implementers must still preserve the declared units, domain, and failure behavior.

## Inspectable interface fixture

The sample below is evidence for interface and validation tests, not a production implementation.

````
{
  "inputs": {
    "stellar_luminosity_L_sun": 1,
    "Teff_K": 5780,
    "requested_boundaries": "conservative_and_optimistic"
  },
  "expected_outputs": {
    "conservative_inner_AU": 0.950443,
    "conservative_outer_AU": 1.676004,
    "optimistic_inner_AU": 0.750312,
    "optimistic_outer_AU": 1.767767
  },
  "reference_data": {
    "runaway_greenhouse_S_eff": 1.107,
    "maximum_greenhouse_S_eff": 0.356,
    "recent_Venus_S_eff": 1.7763,
    "early_Mars_S_eff": 0.32,
    "source_convention": "Widely tabulated standard values from Kopparapu et al. 2013 Table 3, evaluated at Teff = 5780 K"
  },
  "working": "At Teff = 5780 K, T' = 5780 - 5780 = 0 K, so each S_eff equals its tabulated solar-temperature value. Conservative inner = sqrt(1.0 / 1.107) = sqrt(0.903342367) = 0.950443 AU. Conservative outer = sqrt(1.0 / 0.356) = sqrt(2.808988764) = 1.676004 AU. Optimistic inner = sqrt(1.0 / 1.7763) = sqrt(0.562969089) = 0.750312 AU. Optimistic outer = sqrt(1.0 / 0.32) = sqrt(3.125) = 1.767767 AU."
}
````

## Other records

[01**Overview**](<https://guthlabs.ai/docs/instruments/habitable-zone-distance-rough/>)[02**Mechanism**](<https://guthlabs.ai/docs/instruments/habitable-zone-distance-rough/mechanism/>)[04**Qualification**](<https://guthlabs.ai/docs/instruments/habitable-zone-distance-rough/qualification/>)

## Sources and evidence

These pointers bind the page to evidence. They do not grant authority or collapse verification into deployment.

- `VERIFIED_LEDGER.json`

- `evidence-tranche7/tranche7-results.json`