Sirius is two stars: a hot blue-white main-sequence star and the burnt-out core of a heavier star that died first. Sirius B was once several times the Sun’s mass; it exhausted its fuel, shed its outer layers and collapsed into a sphere roughly Earth’s size.
Fly there in 3DNo planet has been confirmed around either star, and searches have been thorough. The white dwarf is proof the system was violently rearranged: whatever orbited Sirius B before it swelled into a red giant did not survive intact.
The pair orbit every 50.09 years on a markedly elliptical path, ranging from about 8 to 32 AU apart.
Sirius B is the nearest white dwarf to the Sun, and the first ever discovered - Alvan Clark saw it in 1862, eighteen years after Bessel predicted it from Sirius A’s wobble.
| Spectral type | A1 V |
| Surface temperature | 9,940 K |
| Mass | 2.063 solar masses |
| Radius | 1.711 solar radii |
| Luminosity | 25.4 times the Sun |
| Apparent magnitude | -1.46 |
| Age | about 0.24 billion years |
| Distance from the Sun | 8.6 light-years (2.6 parsecs) |
| Position (J2000) | RA 101.2872°, Dec -16.7161° |
| Constellation | Canis Major |
A white dwarf the size of Earth carrying the mass of the Sun. A teaspoon of it would weigh several tonnes.
| Planet | Year | Orbit | Radius | Mass | Found |
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Values are the NASA Exoplanet Archive’s composite parameters. A radius marked estimated comes from a mass–radius relation; a mass marked minimum is M sin i. Planet sizes and colours in the 3D view are renderings: none of these worlds has been photographed as more than a point of light.