NGC 346
Young open cluster with nebula in the Small Magellanic Cloud.
NGC 346 is a young open star cluster and its surrounding nebula, found in the Small Magellanic Cloud (SMC) in the constellation Tucana. Scottish astronomer James Dunlop first spotted it on August 1, 1826. J. L. E. Dreyer later described it as bright, large, and very irregular in shape, with a much brighter middle that resembles a double star, and a mottled but unresolved appearance. On the cluster’s edge lies HD 5980, a multiple star system and one of the brightest stars in the SMC.
The cluster sits near the center of the SMC’s brightest H II region, called N66, in the northeast part of the galaxy’s bar. Surveys have found 230 massive OB stars in the cluster’s direction, including 33 O-type stars, 11 of which are type O6.5 or earlier. The inner part of the cluster is densely packed, while the outer area is more spread out. The youngest stars near the center are less than two million years old, and observations indicate that high-mass star formation is still ongoing. The cluster’s star formation rate is estimated at a certain value per year.
Quick Facts
- Epoch
- J2000
- Constellation
- Tucana
- Ra
- 00 · 59 · 05.090
- Dec
- −72 · 10 · 33.24
- Dist Ly
- 210,000 light-years
- Notes
- H II region
- Names
- ESO 51-10, N66
Facts from the source article.
Lore & Background
NGC 346 was discovered on August 1, 1826, by Scottish astronomer James Dunlop. J. L. E. Dreyer described it as 'bright, large, very irregular figure, much brighter middle similar to double star, mottled but not resolved'. The cluster is located near the center of the brightest H II region in the SMC, designated N66, which is positioned in the northeast section of the galactic bar. Stellar surveys have identified 230 massive OB stars in the direction of this cluster, with 33 O-type stars, 11 of which are type O6.5 or earlier. The inner radius of the cluster appears centrally condensed, while the area outside that volume is more dispersed. The youngest cluster members near the center have ages of less than two million years, and observations suggest the cluster is still engaged in high mass star formation. The cluster star formation rate is estimated at a certain value per year. On the outskirts of the cluster is the multiple star system HD 5980, one of the brightest stars in the SMC.
Reader's Guide
NGC 346 holds significance as a young open cluster actively forming high-mass stars, located in the Small Magellanic Cloud. Its association with the brightest H II region in the SMC, N66, makes it a key site for studying star formation processes in a nearby dwarf galaxy. The identification of 230 massive OB stars, including 33 O-type stars, underscores its role as a laboratory for understanding the evolution of massive stars. The presence of HD 5980, one of the brightest stars in the SMC, adds to its importance. The cluster's centrally condensed inner region and more dispersed outer volume, along with ongoing star formation indicated by members younger than two million years, provide insights into the dynamics and lifecycle of stellar clusters. Its legacy is tied to its discovery by James Dunlop in 1826 and its description by J. L. E. Dreyer, which has guided subsequent astronomical study.
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