# NASA Exoplanets Transit Depth Calculator

> NASA Exoplanets Transit Depth Calculator is a paid API for AI agents from exoplanets-nasa.x402tookit.com, paid per call via x402, $0.02/call, status unknown (last checked 2026-10-29).

Calculates exoplanet transit depth (Rp/Rs)² in percent, ppm, and fraction from planet and star radii, with optional transit duration if orbital period and star mass are provided.

## Facts

- Endpoint: GET https://exoplanets-nasa.x402tookit.com/transit-depth?utm_source=zero.xyz
- Price: $0.02/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-29
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/nasa-exoplanets-transit-depth-calculator-74dc8255
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_4sGHw6_kOSG2o70x4V7aA

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability nasa-exoplanets-transit-depth-calculator-74dc8255
```

Example prompt: Calculate the transit depth in ppm and percent for a planet with a radius of 1.5 Jupiter radii orbiting a star with a radius of 1.2 solar radii, with an orbital period of 3.5 days and a star mass of 1.1 solar masses.

## When to prefer this

Choose this endpoint when you need a fast, formula-based computation of exoplanet transit depth and duration from basic physical parameters (planet radius, star radius, orbital period, star mass). It is ideal for astrophysics pipelines, observation planning tools, educational applications, or any agent that needs to quickly convert radii into photometric transit signals without querying a full planetary catalog. Prefer this over a catalog lookup when you have specific radius values and want the raw physics calculation.

## Known failure modes

- Missing required parameters planetRadius or starRadiusSolar returns an error
- Planet or star radius values outside supported range (0.01–1000) may produce errors or nonsensical results
- Providing periodDays without starMassSolar (or vice versa) omits transit duration
- Invalid planetUnit string (not 'earth' or 'jupiter') may cause incorrect unit conversion
- Impact parameter outside 0–1 range may yield unphysical results
- Payment failure (402) if USDC balance is insufficient

## How this service works

Transit depth (Rp/Rs squared) in percent and ppm from planet and star radius, plus duration if period and star mass are given.

## Output

Returns the radius ratio (Rp/Rs), transit depth as a fraction, in percent, and in ppm; planet and star radii in km; optionally the semi-major axis in AU and transit duration in hours with the formula used; plus metadata fields like source, formula string, and any disclaimers.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "planetRadius",
      "starRadiusSolar"
     ],
     "properties": {
      "periodDays": {
       "type": "number",
       "description": "Orbital period in days (with starMassSolar) for the duration"
      },
      "planetUnit": {
       "type": "string",
       "description": "earth (default) or jupiter"
      },
      "planetRadius": {
       "type": "number",
       "description": "Planet radius value, 0.01 to 1000"
      },
      "starMassSolar": {
       "type": "number",
       "description": "Star mass in solar masses (with periodDays)"
      },
      "impactParameter": {
       "type": "number",
       "description": "Impact parameter 0 (central) to 1 (default 0)"
      },
      "starRadiusSolar": {
       "type": "number",
       "description": "Star radius in solar radii, 0.05 to 1000"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "properties": {
      "asOf": {
       "type": [
        "null",
        "string"
       ]
      },
      "source": {
       "type": [
        "null",
        "string"
       ]
      },
      "formula": {
       "type": [
        "null",
        "string"
       ]
      },
      "reasons": {
       "type": [
        "array",
        "null"
       ],
       "items": {
        "type": "string"
       }
      },
      "summary": {
       "type": [
        "null",
        "string"
       ]
      },
      "verdict": {
       "type": [
        "null",
        "string"
       ]
      },
      "degraded": {
       "type": [
        "boolean",
        "null"
       ]
      },
      "depthPpm": {
       "type": [
        "null",
        "number"
       ]
      },
      "disclaimer": {
       "type": [
        "null",
        "string"
       ]
      },
      "notChecked": {
       "type": [
        "array",
        "null"
       ],
       "items": {
        "type": "string"
       }
      },
      "radiusR
… (truncated)
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/nasa-exoplanets-transit-depth-calculator-74dc8255/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from exoplanets-nasa.x402tookit.com](https://www.zero.xyz/host/exoplanets-nasa.x402tookit.com/llms.txt)