Vol. Science · Astronomy · Worlds around other stars

Exoplanets

Planets beyond our solar system — usually orbiting another star in the Milky Way. NASA’s public archive now lists more than 6,000 confirmed worlds (the tally keeps rising), plus thousands of candidates still waiting on follow-up. This desk is a literacy schematic: how we find them, and a curated teaching set of 100+ confirmed examples — firsts, habitable-zone cases, hot Jupiters, imaged giants, microlens and timing worlds — not a dump of the live catalog. Pair with the stars types lesson (why an M dwarf’s habitable zone sits close), the habitable-zone calculator (flux, equilibrium temperature, and the Kopparapu et al. 2014 limits), and the nearest-stars yardstick — Proxima b is the closest known exoplanet, still about four light-years out. For today’s integer, use the NASA Exoplanet Archive.

Educational cartoon, not an ephemeris and not a dump of the NASA Exoplanet Archive. Orbits are scaled to fit; planet sizes are exaggerated. Figures are rounded from NASA Science / NASA Exoplanet Archive public pages (PSCompPars composite). Habitable-zone rings are order-of-magnitude Goldilocks bands for that stellar type — liquid-water possibility, not a life detection. The cited limits are the habitable-zone desk. The dip and the wobble, as numbers, are the transit desk.

Interactive · Discovery methods

Interactive · Teaching set

Glossary · starter terms

Exoplanet

A planet outside our solar system. Most confirmed cases orbit another star; a few are free-floating (rogue) or circle pulsars.

Confirmed vs candidate

A candidate is a likely signal that still needs follow-up. Confirmed worlds have passed extra checks so a false positive (eclipsing binary, starspot, noise) is unlikely.

Transit

Planet crosses the star’s disk and the light curve dips. Depth hints at radius; repeat dips give the period. Alignment is required — we miss most systems this way. The arithmetic is the transit desk.

Radial velocity

The star wobbles toward and away from us. Spectral lines shift blue then red. That gives a minimum mass (m sin i) and the period. The size of that wobble is the same transit desk.

Habitable zone

The Goldilocks band where a rocky planet could hold liquid water. Red-dwarf zones hug the star; Sun-like zones sit near 1 AU. Climate and atmosphere still decide. The rings on this page are a cartoon. The calculation is the habitable-zone desk.

Hot Jupiter

A gas giant on a few-day orbit — 51 Pegasi b’s class. Common in early RV samples because they tug hard and transit often. Not like our Jupiter.

Mini-Neptune / super-Earth

Worlds between Earth and Neptune in size. Super-Earths are often rocky-ish; mini-Neptunes keep thick envelopes. The galaxy is full of them; our solar system is not.

Naming

Host designation + a lowercase letter. The first planet found is b (the star is the unspoken A). Earth as an exoplanet would be Sun d.

Kepler / TESS / JWST

Kepler surveyed one deep field; TESS watches bright nearby dwarfs. JWST does not hunt thousands of new planets — it reads atmospheres of worlds we already have.

Archive, not this page

For the live tally and tables, use the NASA Exoplanet Archive. Counts change weekly.

Astronomy desk

Educational schematic. Discovery-method cartoons follow NASA Science exoplanet facts. World cards use rounded public values from NASA Solar System / Exoplanet pages and the NASA Exoplanet Archive Planetary Systems Composite Parameters table (TAP / PSCompPars) — a curated teaching set, not a precision catalog and not NASA imagery. “More than 6,000 confirmed” is NASA’s 2025–2026 public tally language; check the archive for today’s integer.