Nix — Moon · clAIp

Key facts

Mass (est.)

2.25 × 10¹⁶ kg

0.000000306 Moon masses

Radius

18 km

1% of our Moon's radius

Surface gravity

0.00463 m/s²

0% of Earth's gravity

Orbit around Pluto

24.85 Earth days

Science

Physical

Mass (estimated): 2.25 × 10¹⁶ kg · 0.000000306 Moon masses; Estimated: the implied density (~0.9 g/cm3) is a standard assumed value, so the mass is effectively size-and-density based, not weighed. Source: JPL SSD Planetary Satellite Physical Parameters (GM PLU060).
Radius: 18 km · 1% of our Moon's radius; JPL SSD Planetary Satellite Physical Parameters (mean radius)
Surface gravity: 0.00463 m/s² · 0% of Earth's gravity; Estimated from the estimated mass and radius
Escape velocity: 12.9 m/s · 0% of Earth's escape velocity; Estimated from the estimated mass and radius

Orbit around Pluto

Distance from Pluto: 49,300 km; From JPL orbital elements
Orbital period: 24.9 days; From JPL orbital elements
Eccentricity: 0.015; From JPL orbital elements
Inclination to the J2000 equator: 0.00 °; From JPL orbital elements

Rotation

Rotation: Chaotic — Nix tumbles unpredictably, its spin constantly reshuffled by the shifting pull of the Pluto–Charon binary, with no fixed period (Showalter & Hamilton 2015). Not tidally locked.

Composition

Bulk composition: A predominantly water-ice surface; small and irregular, with a reddish patch.

Radiation & temperature

Insolation: 0.000788 S⊕ · 1/1,269 of the sunlight Earth receives; Computed from the distance to the Sun (inverse-square; Earth's sunlight = 1), before any atmosphere.
Geometric albedo: 0.56; Geometric (V-band) albedo (New Horizons); data limited.
Equilibrium temperature: 38 K (-235 °C); Computed from albedo + distance from the Sun (airless black body); uses the geometric albedo as an estimate

Discovery & history

By: the Hubble Space Telescope Pluto Companion Search Team (Hal Weaver, Alan Stern and colleagues)
Method: Photographic plates
Name: Nyx, the Greek goddess of night and mother of Charon; the initials N and H also honour the New Horizons mission.

Nix was discovered, with Hydra, in Hubble Space Telescope images taken in May 2005 during a search for moons around Pluto ahead of the New Horizons flyby. A small, elongated moon, it tumbles unpredictably through the shifting gravity of the Pluto–Charon binary, and a reddish patch hints at a history unlike its icy surface. Beyond its discovery and the 2015 flyby, little detail is known.

Images

Pluto's moon Nix, imaged by New Horizons — NASA / Johns Hopkins APL / SwRI (public domain) · Wikimedia Commons

Pluto Moon Nix, Half Illuminated — NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute · NASA Image Library

Pluto and its Moons: Charon, Nix, and Hydra — NASA, ESA, H. Weaver JHUAPL, A. Stern SwRI, and the HST Pluto Companion Search Team · NASA Image Library

Capturing Nix and Hydra — NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute · NASA Image Library

Family Portrait of Pluto Moons — NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute · NASA Image Library

Hubble Finds Two Chaotically Tumbling Pluto Moons — artist's impression, not a photograph — NASA/GSFC · NASA Image Library

Final Hazard Search — NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute · NASA Image Library

All Clear for New Horizons — artist's impression, not a photograph — NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute · NASA Image Library

Images from open archives · credit shown per image

Nearby in the catalogue

Orbits

Pluto

Part of

Solar System

Other moons of Pluto · 4