Betelgeuse
Betelgeuse (α Orionis) is a red supergiant star in the constellation Orion. With an apparent magnitude of 0.5 it is the 10th-brightest star in the night sky, and it is about 548 light-years from Earth.
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How to find Betelgeuse, step by step
The orange shoulder of Orion.
- Find Orion's Belt in the south on a winter evening.
- Look above the belt on the left (northeast): the bright orange-red star is Betelgeuse.
- Compare its color with blue-white Rigel on the other side of the belt; Betelgeuse also changes in brightness over months.
Will Betelgeuse explode?
Betelgeuse is a red supergiant that will end as a supernova, but astronomers expect that within roughly the next 100,000 years, not in our lifetime with any certainty. Its "Great Dimming" in 2019–2020 was caused by a cloud of dust it ejected.
Facts
| Constellation | Orion |
|---|---|
| Designation | α Orionis (Alpha Orionis), HR 2061 |
| Apparent magnitude | 0.5 (10th brightest) |
| Spectral type | M1-2Ia-Iab |
| Color | red (B−V 1.85) |
| Distance | about 548 light-years |
| Right ascension | 5 h 55.2 min |
| Declination | +7.41° |
| Best month | February (at about 9 pm) |
How to find Betelgeuse
Betelgeuse is in Orion. From 40° N it is highest in the south in February evenings, about 57° above the horizon. From 35° S it reaches about 48° in the north. Nearby bright stars: Bellatrix (8° away), Mintaka (10° away) and Alnilam (10° away).