Conservative HZ Width for Stellar Luminosity Calculator
Conditional width HZ endpoints from caller independently applicable effective-flux criteria; no proof of water, atmosphere or life.
Description
Conservative HZ Width for Stellar Luminosity Calculator: return inner au, outer au, width au.
This tool calculates a habitable-zone width from supplied runaway-greenhouse inner and maximum-greenhouse outer limits. These are climate-model thresholds, not measurements of a planet’s surface conditions.
The results are the inner radius, outer radius and their difference, all in astronomical units (AU). You supply both the stellar luminosity and the two flux thresholds.
When to use this tool
Use this tool when the supplied inputs match the specific operation described above and you need a repeatable result under its stated convention.
- Check the supported input and output contract against an existing calculation or observation.
- Use the complete example to confirm units, selector spelling and result interpretation.
How to use the tool and how it works
- Enter luminositySolar and both effective-flux thresholds using the units defined below. The inner threshold must exceed the outer threshold.
- Run the calculation. Correct input errors before interpreting the result.
- Read innerAu and outerAu as distances in AU, and widthAu as outerAu minus innerAu. Assess the supplied model thresholds separately.
Enter luminositySolar as the luminosity ratio L/L_sun. Each effective-flux input is a dimensionless ratio to present solar irradiance at Earth’s orbital distance of 1 AU: 1 means that reference irradiance. Do not enter a flux in W/m². With these normalized inputs, the relation sqrt(luminositySolar / effectiveFlux) returns a distance in AU.1
The tool calculates innerAu = sqrt(luminositySolar / callerRunawayGreenhouseFlux) and outerAu = sqrt(luminositySolar / callerMaximumGreenhouseFlux), then returns widthAu = outerAu - innerAu. It rejects inputs unless callerRunawayGreenhouseFlux exceeds callerMaximumGreenhouseFlux.2
| Input field | Meaning and units | Accepted input |
|---|---|---|
| luminositySolar | Stellar luminosity divided by solar luminosity (L/L_sun); dimensionless. A value of 1 represents a solar-luminosity star. | Finite number; greater than zero |
| callerRunawayGreenhouseFlux | Runaway-greenhouse inner-boundary incident flux divided by present solar irradiance at 1 AU; dimensionless. | Finite number; greater than zero |
| callerMaximumGreenhouseFlux | Maximum-greenhouse outer-boundary incident flux divided by present solar irradiance at 1 AU; dimensionless. | Finite number; greater than zero |
| Output field | Interpretation |
|---|---|
| result | Object containing the following named result fields. |
| result.innerAu | Inner-boundary distance from the star, in AU. |
| result.outerAu | Outer-boundary distance from the star, in AU. |
| result.widthAu | Outer radius minus inner radius, in AU. |
{
"input": {
"luminositySolar": 1,
"callerRunawayGreenhouseFlux": 1,
"callerMaximumGreenhouseFlux": 0.25
},
"output": {
"result": {
"innerAu": 1,
"outerAu": 2,
"widthAu": 1
}
}
}Limitations and assumptions
- The tool does not calculate temperature-dependent flux criteria, climate or evidence of life.
- Every declared field is required and unexpected fields are rejected. Numeric inputs must be finite; input errors are distinct from a valid false result or an explicitly qualified output.
- Extremely large inputs and nonfinite or excessively large outputs are rejected. List positions reported by the tool use zero-based indices unless stated otherwise.
Alternative or Complementary methods
For an optimistic comparison, the POE model scales reference distances of 0.75 AU (recent Venus) and 1.77 AU (early Mars) by sqrt(luminositySolar). These empirical limits differ from the runaway- and maximum-greenhouse criteria used here.3
References
-
Kopparapu et al. (2013): Habitable Zones Around Main-Sequence Stars: New Estimates — arXiv
-
Tool behavior and example: Conservative HZ Width for Stellar Luminosity Calculator — tool.io
-
POE calculations: optimistic recent-Venus and early-Mars habitable-zone limits — NASA Exoplanet Archive, Caltech/IPAC
Similar or alternative tools
- Optimistic Venus-Mars HZ Limits Estimator Calculator
Calculate optimistic limits from explicit flux inputs. To reproduce POE scaling, supply callerRecentVenusFlux = 1.7777777777777777 and callerEarlyMarsFlux = 0.3191930798940279, using the same luminositySolar. These are supplied inputs, not built-in defaults.
- Habitable Zone Outer Maximum Greenhouse Boundary Calculator
Conditional maximum-greenhouse HZ outer radius in AU using independently applicable effective flux; no atmospheric/habitability calculation.