| NGC 2509 | |
| Epoch: | J2000 |
| Constellation: | Puppis |
| Ra: | [1] |
| Dist Ly: | 9,500 ly |
| Dist Pc: | 2,900 pc |
| Appmag V: | 9.3[2] |
| Size V: | 2.5 ± 0.5 |
| Age: | 1,200 Myr |
| Names: | NGC 2509, Cr 171, Mel 81, OCl 630 |
NGC 2509 is an open cluster in the constellation of Puppis. It was discovered on 3 December 1783 by William Herschel.[3] It was described as "bright, pretty rich, slightly compressed" by John Louis Emil Dreyer, the compiler of the New General Catalogue.[3]
The cluster is about 14 light-years (4.2 parsecs) wide,[1] but the cluster's other parameters remain poorly known. Some studies have estimated a distance of about 9,500 light-years (2,900 parsecs) away from the Solar System,[1] while older estimates put it at only 2980 light-years (912 parsecs) away.[4] Estimates of the cluster's age have also varied significantly, from 1.2 billion years old[1] to 8 billion years old.[4] The latest analysis based on the parallaxes measured by the Gaia spacecraft confirms that it is a relatively distant object, with a distance between 2500 and 3000 parsecs.[5]