M5 is an ancient globular cluster in Serpens, containing more than 100,000 stars in the halo of the Milky Way.
What It Is
M5, also cataloged as NGC 5904, is a bright globular cluster in Serpens. It is a dense, gravitationally bound swarm of ancient stars orbiting in the halo of the Milky Way.
History
Gottfried Kirch discovered M5 in 1702 while following a comet, and Charles Messier added it to his catalog in 1764 as a fuzzy object to avoid confusing with comets. William Herschel later resolved it into stars, revealing that the apparent nebula was actually a rich stellar cluster.
Science Notes
- NASA describes M5 as containing 100,000 stars or more packed into a region about 165 light-years across.
- M5 is one of the oldest known Milky Way globular clusters, with stars estimated to be nearly 13 billion years old.
- Its dense stellar environment includes evolved red and blue giant stars as well as blue stragglers, stars that appear younger and bluer than the cluster age would suggest.
- distance
- ~25,000 light-years
- diameter
- ~165 light-years
- age
- nearly 13 billion years
- stars
- 100,000+ stars
- apparentMagnitude
- +6.65
- constellation
- Serpens
