Betelgeuse in the winter triangle

Orion α, the fourth star of Betelgeuse, is a red Supergiant star in Orion. It is the tenth brightest star in the night sky, 643 light years away from the sun. In the winter night sky, it forms a winter triangle with Sirius in Canis major and Nanhe III in Canis minor. Although it is the alpha star of Orion, the actual beta star of Orion (Betelgeuse) is brighter than it, because it is a variable star whose brightness changes periodically.

Basic data of Betelgeuse

Constellation: Orion

Star position: right ascension 05h 55m 10.3053s, declination+07 24 ′ 25.426 ″.

Visual magnitude (V): 0.58 (0.3–1.2)

Spectral classification: M2Iab (red Supergiant star), B-V color index 1.85 (orange red), U-B color index 2.06.

Variable star type: SR c (semi-regular variable star)

Radial velocity (RV):+2 1.0 km/s, self-propelled (μ) μ)Ra:24.95±0.08 mas/year, dec: 9.56 0.15 mas/year.

Stellar parallax (π): 5.07 1. 10 mas.

Absolute magnitude (MV):? 5. 14

Star mass: 14 M☉

Star radius: 630 R☉

Stellar brightness: 63000 (40000–100000) l χ

Surface temperature: 3500K

Rotation period: 17 years (14.6 km/s)

Other names: Orion α, Alpha Orion is, 58 ori, HIP 274 1, BD+7 1055, HD 3980 1, Sao 1 1327 1, fk.