GJ 504 b

Planet· orbits GJ 504

GJ 504 b — a DIRECTLY IMAGED giant planet, famous for its colour: it is inferred to glow a deep magenta or cherry-blossom PINK, because it is young and warm (~500 K) with little cloud to whiten its glow. It orbits far out (~44 AU) around a Sun-like star. Its mass (~4 Jupiter masses) comes from its brightness and age; its size is a model estimate, so no density is quoted. One of the coldest, lowest-mass planets ever photographed.

Open in 3D viewSee GJ 504 b in the live, interactive 3D map

Key facts

Mass

7.59 × 10²⁷ kg

4 M♃ (1,271 M⊕)

Year

260 Earth years

94,875 Earth days

Distance from GJ 504

43.5 AU

Science

Physical

Mass: 7.59 × 10²⁷ kg · 4 M♃ (1,271 M⊕)
Radius: Not measured; Directly imaged: the mass (~4 Jupiter) and size are model estimates from the planet's own glow and the system's age, not measured geometrically, so no density is quoted.

Orbital

Semi-major axis: 43.5 AU; From the NASA Exoplanet Archive (direct imaging + orbit estimate)
Eccentricity: 0; From the NASA Exoplanet Archive (direct imaging + orbit estimate)
Inclination: 0.00 °; From the NASA Exoplanet Archive (direct imaging + orbit estimate)
Orbital period: 259.75 years; From the NASA Exoplanet Archive (direct imaging + orbit estimate)
Perihelion: 43.5 AU; Computed from the orbital elements
Aphelion: 43.5 AU; Computed from the orbital elements
Mean orbital velocity: 4.99 km/s; Computed from the orbital elements

Composition

Bulk composition: A young, self-luminous giant of ~4 Jupiter masses orbiting far out (~44 AU). It is one of the coldest, lowest-mass planets ever DIRECTLY IMAGED, and is famously inferred to glow a deep magenta or cherry-blossom PINK — because at ~500 K it is warm enough to shine in its own light but too cool for the whitening clouds of hotter giants. The real telescope image (a faint dot) is in the gallery.
Cloud appearance: Appearance based on NASA/JPL-Caltech's artist's concept. No spacecraft has imaged this world, so its real appearance is unknown — The banded clouds shown are a representation of its class, shown only in Visual mode; Realism shows a plain spectral colour.

Radiation & temperature

Insolation: 0.00114 S⊕ · 1/876 of the sunlight Earth receives; Computed from GJ 504's luminosity and the orbital distance (inverse-square; Earth's sunlight = 1).
Equilibrium temperature: 510 K (237 °C); A modelled temperature from its own heat (it is young and self-luminous), not an equilibrium value — this warmth is why it is inferred to glow pink.

Discovery & history

Method: Directly imaged
Name: A Gliese-Jahreiß designation; no IAU proper name.

Directly imaged in 2013 by the Subaru telescope (SEEDS survey) — a rare picture of a planet, and one whose modelled temperature makes it glow a striking pink.

Images

Artist's concept of GJ 504 b, inferred to glow a deep magenta PINK from its own heat — an artist's impression, not a photograph. — NASA's Goddard Space Flight Center / S. Wiessinger (public domain) · Wikimedia Commons

A REAL near-infrared image of GJ 504 b (the dot at upper right) directly imaged beside its star by the Subaru Telescope — an actual photograph; the star's glare is masked. — NASA's Goddard Space Flight Center / M. Kuzuhara et al. (public domain) · Wikimedia Commons

Images from open archives · credit shown per image