Arcturus
HR 5340 · HIP 69673 · α Boo
👁️ Naked-eye
📋 A written introduction is coming — for now this page shows official values only.
Star
- Apparent magnitude
- -0.05 mag
- Parallax
- 88.83 mas → about 36.7 light-years away
- Spectral type
- K2IIIp
- Right ascension
- 213.9153°
- Declination
- 19.1824°
- Designation
- HR 5340
- Bayer designation
- α Boo
- HIP number
- 69673
- IAU name adopted
- 2016-06-30
- Name language
- Greek
- Name origin (IAU)
- From its ancient Greek name Ἀρκτοῦρος, "the Guard, or Guardian". Reapplied in Early Modern times. As the Greek word Άρκτος, "bear," also came to mean "north," the meaning can ambiguously be "Guardian of the North" and "Guardian of the Bear", referring to the nearby constellation Ursa Major.
Source:IAU Working Group on Star Names · checked 2026-11-02 ↗ESA Hipparcos Catalogue (ESA Gaia Archive) · checked 2026-11-03 ↗
Related
Constellation
In everyday life
- Light from this object takes about 37 years to reach Earth — the light you see tonight left around AD 1989 (official distance ÷ speed of light).
- At magnitude -0 it is bright enough for the naked eye (limit about 6) — look from somewhere dark.
- Declination 19.2° — it rises above the horizon in Seoul (37.6° N), so it is visible from Korea in the right season.