Sirius, the Dog Star, is the brightest star in Earth's night sky. Its proximity and luminosity have made it a subject of intense astronomical study for centuries. This page presents key astrometric data, derived from precise measurements of its position, motion, and parallax, providing fundamental insights into its physical properties and its place within our galactic neighborhood.
| Parameter | Value (approx.) | Unit |
|---|---|---|
| Right Ascension (RA) | 06h 45m 08.917s | |
| Declination (Dec) | -16° 42' 58.03" | |
| Parallax | 379.23 ± 0.08 | milliarcseconds (mas) |
| Proper Motion (RA) | -546.00 | mas/year |
| Proper Motion (Dec) | -289.95 | mas/year |
| Distance | 2.64 | parsecs (pc) |
| Distance | 8.60 | light-years (ly) |
The astrometric data points are crucial for understanding Sirius's trajectory through space and its relationship with other stars. The parallax measurement allows us to directly calculate its distance, while proper motion reveals its movement relative to the Sun. The binary nature of Sirius, with the white dwarf Sirius B in orbit around Sirius A, adds further complexity to its dynamic system.