Kruger 60 B

Star

Kruger 60 B (DO Cephei) - the fainter red dwarf of the Kruger 60 pair, and a vigorous flare star that can briefly double in brightness. About a sixth of the Sun's mass.

Open in 3D viewSee Kruger 60 B in the live, interactive 3D map

Key facts

Mutual orbit

44.7 Earth years

16,316 Earth days

Mass

3.50 × 10²⁹ kg

0.176 M☉

Radius

166,968 km

24% of the Sun's radius

Surface temperature

2,890 K (2,617 °C)

Luminosity

1.30 × 10²⁴ W

Spectral type

M4V (red flare star)

Science

Physical

Mass: 3.50 × 10²⁹ kg · 0.176 M☉
Radius: 166,968 km · 24% of the Sun's radius
Density: 17,953 kg/m³ · 18× water; Computed from mass and radius
Spectral type: M4V (red flare star)

Motion through space

Note: The motion of the pair's common centre of mass, computed as the mass-weighted mean of its stars' catalogued motions.
Proper motion: 0.904 arcseconds per year · its drift across our sky; SIMBAD — 2018yCat.1345....0G
Speed across our line of sight: 17.2 km/s; Computed from proper motion and parallax

Orbit (around the system barycenter)

Semi-major axis: 5.76 AU; From the visual-binary orbit (Heintz; P = 44.6 yr, a = 9.5 AU, e = 0.41)
Eccentricity: 0.41; From the visual-binary orbit (Heintz; P = 44.6 yr, a = 9.5 AU, e = 0.41)
Orbital period: 44.67 years; From the visual-binary orbit (Heintz; P = 44.6 yr, a = 9.5 AU, e = 0.41)

Composition

By mass: A red dwarf about 18% of the Sun's mass that can briefly double in brightness during flares.

Temperature

Surface: 2,890 K (2,617 °C)

Radiation & temperature

Luminosity: 1.30 × 10²⁴ W · 0.0034 L☉
Surface temperature: 2,890 K (2,617 °C)
Peak wavelength: 1003 nm · near-infrared (mostly invisible to the eye); Computed (Wien's law) from the surface temperature

Discovery & history

Discovered: 1890
By: Adalbert Kruger
Method: Telescope
Name: 'Kruger 60 B' is the fainter component of the binary; its flaring earned the variable-star name DO Cephei.

Its dramatic flares, first noted in the 20th century, earned it the variable-star name DO Cephei.

Images

Where to find it — in Cepheus, the King (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