Equilibrium Temperature

{
  "albedo": 0.3,
  "asOf": "2026-10-11T08:48:41.724Z",
  "degraded": false,
  "disclaimer": "Screening signal computed from the named public source. Not financial, legal or investment advice; provided as is. Verify at the source before acting.",
  "equilibriumC": -18.572,
  "equilibriumF": -1.4293,
  "equilibriumK": 254.58,
  "insolationEarth": 1,
  "luminosityDerivedFromTeffAndRadius": false,
  "luminositySolar": 1,
  "notChecked": [
    "the greenhouse effect and atmosphere: Venus and Earth's real surface temperatures differ strongly from equilibrium",
    "day-night and latitude differences (heat is assumed spread evenly over the whole surface)",
    "…2 more"
  ],
  "orbitAu": 1,
  "reasons": [
    "T = ((S (1 - A)) / (4 sigma))^(1/4) with S = 1361 W/m2 x L / a^2: heat spread evenly over the planet, no atmosphere.",
    "The NASA Exoplanet Archive's own pl_eqt column matches the zero-albedo case.",
    "…1 more"
  ],
  "source": "computed locally",
  "summary": "At 1 au from a 1 L-sun star with albedo 0.3, the equilibrium temperature is 254.6 K (-18.57 C, -1.429 F).",
  "verdict": "COMPUTED",
  "zeroAlbedoK": 278.32
}

# bash or zsh: see the payment challenge. Nothing is charged.
curl -sS -g -i 'https://exoplanets-nasa.x402tookit.com/equilibrium-temperature?albedo=0.3&luminositySolar=1&orbitAu=1'

# x402 v2 sends the challenge base64-encoded in the PAYMENT-REQUIRED header (v1 sends it in the body).
# To read the header:
curl -sS -g -o /dev/null -D - 'https://exoplanets-nasa.x402tookit.com/equilibrium-temperature?albedo=0.3&luminositySolar=1&orbitAu=1' \
  | grep -i '^payment-required:' | cut -d' ' -f2 | tr -d '\r' | base64 --decode

// npm i @x402/fetch @x402/evm viem
import { wrapFetchWithPayment, x402Client } from "@x402/fetch";
import { registerExactEvmScheme } from "@x402/evm/exact/client";
import { privateKeyToAccount } from "viem/accounts";

// Pays at most $0.02 per call.
const client = new x402Client().setSpendControls({ maxAmountPerPayment: "$0.02" });
registerExactEvmScheme(client, { signer: privateKeyToAccount(process.env.EVM_PRIVATE_KEY) });
const pay = wrapFetchWithPayment(fetch, client);

// Not sure it's safe to pay? ToolVet checks it first for $0.005. Pay for that from a separate
// client: this one is capped at $0.02 per payment. GET https://toolvet.app/api/v1/check?url=https%3A%2F%2Fexoplanets-nasa.x402tookit.com%2Fequilibrium-temperature
const res = await pay("https://exoplanets-nasa.x402tookit.com/equilibrium-temperature?albedo=0.3&luminositySolar=1&orbitAu=1");
console.log(res.status, await res.text());

# pip install "x402[requests,evm]"
import os
from eth_account import Account
from x402 import x402ClientSync
from x402.http.clients import x402_requests
from x402.mechanisms.evm import EthAccountSigner
from x402.mechanisms.evm.exact.register import register_exact_evm_client

# Pays at most $0.02 per call.
client = x402ClientSync().set_spend_controls({"max_amount_per_payment": "$0.02"})
register_exact_evm_client(client, EthAccountSigner(Account.from_key(os.environ["EVM_PRIVATE_KEY"])))

with x402_requests(client) as session:
    res = session.get("https://exoplanets-nasa.x402tookit.com/equilibrium-temperature?albedo=0.3&luminositySolar=1&orbitAu=1")
    print(res.status_code, res.text)