YZ Ceti
Star
YZ Ceti - a small red flare star 12.1 light-years away in Cetus, host to three of the lowest-mass planets known, all packed inside a 5-day span. One of the nearest compact multi-planet systems.
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Key facts
Mass
2.82 × 10²⁹ kg
0.142 M☉
Radius
109,225 km
16% of the Sun's radius
Surface temperature
3,151 K (2,878 °C)
Luminosity
8.42 × 10²³ W
Spectral type
M4.5V (red dwarf)
Science
Physical
- Mass
- 2.82 × 10²⁹ kg · 0.142 M☉
- Radius
- 109,225 km · 16% of the Sun's radius
- Density
- 51,743 kg/m³ · 52× water
- Computed from mass and radius
- Spectral type
- M4.5V (red dwarf)
Motion through space
- Proper motion
- 1.36 arcseconds per year · its drift across our sky
- SIMBAD — 2020yCat.1350....0G, 2018MNRAS.475.1960F
- Radial velocity
- +28.3 km/s · moving away from the Sun
- SIMBAD — 2020yCat.1350....0G, 2018MNRAS.475.1960F
- Speed across our line of sight
- 24 km/s
- Computed from proper motion and parallax
- Speed through space, relative to the Sun
- 37.1 km/s
- Computed from proper motion, parallax and radial velocity
Composition
- By mass
- A red dwarf about 14% of the Sun's mass; a flare star that brightens abruptly.
Temperature
- Surface
- 3,151 K (2,878 °C)
Radiation & temperature
- Luminosity
- 8.42 × 10²³ W · 0.0022 L☉
- Surface temperature
- 3,151 K (2,878 °C)
- Peak wavelength
- 920 nm · near-infrared (mostly invisible to the eye)
- Computed (Wien's law) from the surface temperature
Discovery & history
- Method
- Telescope
- Name
- Named for its variable-star designation YZ Ceti (a flare star in Cetus); also GJ 54.1.
A long-known flare star; in 2017 ESO's HARPS revealed three small planets, among the least-massive ever found by the radial-velocity method.
Images
Images from open archives · credit shown per image