EZ Aquarii C

Star

EZ Aquarii C - the third, outermost red dwarf of the EZ Aquarii triple, orbiting the close inner pair every 2.3 years. Like its companions it is a gently flaring star barely a tenth of the Sun's mass.

Open in 3D viewSee EZ Aquarii C in the live, interactive 3D map

Key facts

Mutual orbit

823 Earth days

2.25 Earth years

Mass

2.28 × 10²⁹ kg

0.114 M☉

Radius

97,398 km

14% of the Sun's radius

Surface temperature

2,850 K (2,577 °C)

Luminosity

2.30 × 10²³ W

Spectral type

M5V (red dwarf)

Science

Physical

Mass: 2.28 × 10²⁹ kg · 0.114 M☉
Radius: 97,398 km · 14% of the Sun's radius
Density: 58,842 kg/m³ · 59× water; Computed from mass and radius
Spectral type: M5V (red dwarf)

Motion through space

Note: Catalogued for the system as a whole: the motion of its stars' common centre of mass.
Proper motion: 3.26 arcseconds per year · its drift across our sky; SIMBAD — 2012yCat.1322....0Z
Speed across our line of sight: 52.6 km/s; Computed from proper motion and parallax

Orbit (around the system barycenter)

Semi-major axis: 0.766 AU; From the triple-system orbit of Delfosse et al. 1999 (outer pair P = 822.6 d, e = 0.44; the inner pair is an unresolved 3.79-day spectroscopic binary)
Eccentricity: 0.439; From the triple-system orbit of Delfosse et al. 1999 (outer pair P = 822.6 d, e = 0.44; the inner pair is an unresolved 3.79-day spectroscopic binary)
Orbital period: 2.25 years; From the triple-system orbit of Delfosse et al. 1999 (outer pair P = 822.6 d, e = 0.44; the inner pair is an unresolved 3.79-day spectroscopic binary)

Composition

By mass: A red dwarf about a tenth of the Sun's mass; a flare star.

Temperature

Surface: 2,850 K (2,577 °C)

Radiation & temperature

Luminosity: 2.30 × 10²³ W · 0.0006 L☉
Surface temperature: 2,850 K (2,577 °C)
Peak wavelength: 1017 nm · near-infrared (mostly invisible to the eye); Computed (Wien's law) from the surface temperature

Discovery & history

Discovered: 1999
By: X. Delfosse et al.
Method: Telescope
Name: The third component (C) of the EZ Aquarii / GJ 866 triple system.

Resolved as the third component of the triple by Delfosse et al. (1999) from precise infrared imaging and radial velocities.

Images

Where to find it — in Aquarius, the Water-Bearer (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