Luyten 726-8 B
Star
Luyten 726-8 B (UV Ceti) — the fainter twin, and the PROTOTYPE flare star after which the whole 'UV Ceti' class of flaring red dwarfs is named. A tiny M6V dwarf, it can brighten severalfold within seconds when a flare erupts, then fade back. It orbits its near-identical companion every ~26 years.
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Key facts
Mutual orbit
26.3 Earth years
9,599 Earth days
Mass
2.38 × 10²⁹ kg
0.119 M☉
Radius
110,616 km
16% of the Sun's radius
Surface temperature
2,650 K (2377 °C)
Luminosity
4.21 × 10²³ W
Spectral type
M6V (red dwarf; the prototype UV Ceti variable)
Science
Physical
- Mass
- 2.38 × 10²⁹ kg · 0.119 M☉
- Radius
- 110,616 km · 16% of the Sun's radius
- Density
- 41,922 kg/m³ · 42× water
- Spectral type
- M6V (red dwarf; the prototype UV Ceti variable)
Orbit (around the system barycenter)
- Semi-major axis
- 2.82 AU
- Eccentricity
- 0.617
- Orbital period
- 26.28 years
Composition
- By mass
- A tiny red dwarf (~0.12 M☉, ~2650 K) famous for dramatic, rapid optical flares — it can brighten severalfold within seconds. Such flaring red dwarfs are now called 'UV Ceti variables' after this star.
Temperature
- Surface
- 2,650 K (2377 °C)
Radiation & temperature
- Luminosity
- 4.21 × 10²³ W · 0.0011 L☉
- Surface temperature
- 2,650 K (2377 °C)
- Peak wavelength
- 1093 nm · near-infrared (mostly invisible to the eye)
Discovery & history
- Discovered
- January 1, 1948
- By
- Willem Jacob Luyten
- Name
- 'UV Ceti' is its variable-star designation in Cetus — now the name of the entire class of flaring red dwarfs it typifies.
Recognised in 1948, with its companion, from Willem Luyten's proper-motion work. Its dramatic, rapid optical flares made it the defining example of a flare star; such stars are now called UV Ceti variables in its honour.
Images
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