Kepler-90

Star

Kepler-90 — a yellow-white star a little larger and hotter than the Sun (~1.2 solar masses and radii), ~2,770 light-years away in Draco. Ordinary in itself, it is remarkable for what orbits it: a full family of eight planets, the Solar System's equal.

Open in 3D viewSee Kepler-90 in the live, interactive 3D map

Key facts

Mass

2.39 × 10³⁰ kg

1.2 M☉

Radius

834,840 km

1.2× wider than the Sun

Surface temperature

6,080 K (5,807 °C)

Spectral type

G-type dwarf (a little hotter and larger than the Sun)

Science

Physical

Mass: 2.39 × 10³⁰ kg · 1.2 M☉
Radius: 834,840 km · 1.2× wider than the Sun
Density: 979 kg/m³ · 0.98× water; Computed from mass and radius
Spectral type: G-type dwarf (a little hotter and larger than the Sun)

Motion through space

Proper motion: 0.00543 arcseconds per year · its drift across our sky; SIMBAD — 2020yCat.1350....0G, 2022yCat.1355....0G
Radial velocity: -15.5 km/s · approaching the Sun; SIMBAD — 2020yCat.1350....0G, 2022yCat.1355....0G
Speed across our line of sight: 22 km/s; Computed from proper motion and parallax
Speed through space, relative to the Sun: 27 km/s; Computed from proper motion, parallax and radial velocity

Composition

By mass: A yellow-white main-sequence star of about 1.2 solar masses and radii, hydrogen/helium like the Sun. Notable not for itself but for its full family of eight transiting planets — the only star known to tie the Sun's count.

Temperature

Surface: 6,080 K (5,807 °C)

Radiation & temperature

Luminosity: 6.79 × 10²⁶ W · 1.77 L☉
Surface temperature: 6,080 K (5,807 °C)
Peak wavelength: 477 nm · blue light; Computed (Wien's law) from the surface temperature

Discovery & history

Method: Telescope
Name: A Kepler-mission catalogue designation; no proper name.

Monitored by NASA's Kepler telescope, its light showed the tell-tale dips of many transiting planets; seven were confirmed by 2013 and an eighth by machine learning in 2017.

Images

NASA/JPL diagram comparing the eight planets of Kepler-90 with the Solar System — the only known star to tie the Sun's planet count (a diagram, not a photograph). — NASA/JPL-Caltech (public domain) · Wikimedia Commons

NASA illustration of the Kepler-90 system, released when its record-tying eighth planet was found — an artist's diagram, not a photograph. — NASA/Ames Research Center/Wendy Stenzel (public domain) · Wikimedia Commons

Where to find it — in Draco, the Dragon (IAU constellation chart). To the eye it is a single point of light; no telescope has imaged its surface. — IAU / Sky & Telescope, R. Sinnott & R. Fienberg (CC BY 3.0) · Wikimedia Commons

Images from open archives · credit shown per image