# NASA Exoplanets - Host Star Planet Catalog

> NASA Exoplanets - Host Star Planet Catalog 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).

Returns all confirmed exoplanets orbiting a named host star, with stellar properties and each planet's orbital period, size class, and habitable-zone position.

## Facts

- Endpoint: GET https://exoplanets-nasa.x402tookit.com/host-star-planets?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-host-star-planet-catalog-8b8b9da9
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_AIwT4kHxr2fi7TsHXMPZl

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-host-star-planet-catalog-8b8b9da9
```

Example prompt: Can you pull up all the confirmed planets orbiting TRAPPIST-1, including which ones are in the habitable zone and what the star itself is like — mass, temperature, distance from us?

## When to prefer this

Use this endpoint when you need a comprehensive per-star planetary catalog including both stellar context and individual planet properties in a single call. Prefer this over individual planet endpoints when surveying an entire multi-planet system, checking habitable-zone membership across all planets of a host star, or enriching star-specific research with structured planet data.

## Known failure modes

- Star name not found in NASA archive returns empty planet array or null star object
- Misspelled or ambiguous star names may return no results
- Some star or planet fields may be null if data is not available in the archive
- Network or upstream NASA API outage returns error response
- Degraded mode flag may indicate partial data availability

## How this service works

All confirmed planets of a host star by name, with star properties and each planet's period, size and habitable-zone position.

## Output

A JSON object containing the host star's properties (name, mass, radius, spectral type, temperature, luminosity, age, distance) and an array of all confirmed orbiting planets, each with name, orbital period, radius, mass, size class, insolation, equilibrium temperature, habitable-zone position, discovery year, and discovery method. Also includes a summary, verdict, and data source attribution.

## 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": [
      "star"
     ],
     "properties": {
      "star": {
       "type": "string",
       "description": "Host star name, for example TRAPPIST-1, Kepler-90 or Proxima Cen"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "properties": {
      "asOf": {
       "type": [
        "null",
        "string"
       ]
      },
      "star": {
       "type": [
        "null",
        "object"
       ],
       "properties": {
        "name": {
         "type": [
          "null",
          "string"
         ]
        },
        "ageGyr": {
         "type": [
          "null",
          "number"
         ]
        },
        "massSolar": {
         "type": [
          "null",
          "number"
         ]
        },
        "radiusSolar": {
         "type": [
          "null",
          "number"
         ]
        },
        "spectralType": {
         "type": [
          "null",
          "string"
         ]
        },
        "temperatureK": {
         "type": [
          "null",
          "number"
         ]
        },
        "starsInSystem": {
         "type": [
          "null",
          "number"
         ]
        },
        "distanceParsecs": {
         "type": [
          "null",
          "number"
         ]
        },
        "distanceLightYears": {
         "type": [
          "null",
          "number"
         ]
        },
        "luminosityLog10Solar": {
         "type": [
          "null",
          "number"
         ]
        }
       }
      },
      "source": {
       "type": [
        "null",
        "string"
       ]
      },
      "planets": {
       "type": [
        "array",
        "null"
       ],
       "items": {
        "type": "object",
        "properties": {
         "host": {
          "type": [
           "null",
           "string"
          ]
         },
         "name": {
          "type": [
           "null",
   
… (truncated)
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/nasa-exoplanets-host-star-planet-catalog-8b8b9da9/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)