Wild Duck Cluster
A rich, compact open cluster in Scutum, discovered in 1681.
The Wild Duck Cluster, cataloged as Messier 11 and NGC 6705, is an open star cluster located in the constellation Scutum (the Shield). Gottfried Kirch first spotted it in 1681, and Charles Messier added it to his catalog of diffuse objects in 1764. Its nickname comes from a triangular arrangement of its brighter stars, which some see as a flock of ducks in flight, while others interpret it as a single swimming duck. The cluster sits just east of the midpoint of the Scutum Star Cloud.
Among open clusters, the Wild Duck is both exceptionally rich and tightly packed, and it ranks as one of the most massive known. Its age is estimated at roughly 316 million years. The core spans 1.23 parsecs (4.0 light-years), while the tidal radius extends to 29 parsecs (95 light-years). Mass estimates vary from 3,700 to 11,000 solar masses, depending on the calculation method. The brightest star in the cluster has a visual magnitude of 8, and the cluster contains 870 members down to magnitude 16.5. Its integrated absolute magnitude is –6.5, with a visual extinction of 1.3 magnitudes.
The cluster is metal-rich, with an iron abundance of [Fe/H] = 0.17±0.04. Despite its relative youth, it shows an enhancement of alpha process elements, possibly because its birth molecular cloud was enriched by a nearby Type II supernova. At least nine variable stars are high-probability members, along with 29 lower-probability candidates; among the former are two eclipsing binary systems. The cluster lies 6.8 kiloparsecs (22,000 light-years) from the Galactic Center, near the galactic plane, and has not drifted far from its original birthplace.
Quick Facts
- Epoch
- J2000.0
- Constellation
- Scutum
- Ra
- 18 · 51 · 05.0
- Dec
- -06 · 16 · 12
- Dist Ly
- 1877 pc
- Appmag V
- 5.8
- Mass Msol
- 11,000
- Radius Ly
- 29 pc
- Names
- Messier 11, NGC 6705, Cr 391, Mel 213, OCl 76.0
Facts from the source article.
Lore & Background
The Wild Duck Cluster was discovered by Gottfried Kirch in 1681. Charles Messier included it in his catalogue of diffuse objects in 1764. Its popular name derives from the brighter stars forming a triangle which could resemble a flying flock of ducks (or, from other angles, one swimming duck). The cluster is located just to the east of the Scutum Star Cloud midpoint.
The cluster is metal-rich with an iron abundance of [Fe/H] = 0.17±0.04. Despite its youth, it shows an enhancement of alpha process elements. Possibly this is due to an enhancement of its birth molecular cloud by a nearby Type II supernova explosion. At least nine variable star members have been identified with high probability, plus 29 lower probability members. The former include two eclipsing binary star systems.
The cluster is located 6.8 kpc (22,000 ly) from the Galactic Center, close to the galactic plane, and is not far from its birthplace. Estimates for the cluster's mass range from 3,700 M☉ to 11,000 M☉, depending on the method chosen.
Reader's Guide
The Wild Duck Cluster is significant as one of the richest and most compact open clusters known, and one of the most massive. Its extensive study has provided insights into stellar populations and cluster dynamics. The cluster's age is estimated at about 316 million years. Its core radius is 1.23 pc (4.0 ly) while the tidal radius is 29 pc (95 ly). The brightest cluster member has visual magnitude 8, and it has 870 members of at least magnitude 16.5. It has an integrated absolute magnitude of –6.5, and a visual extinction of 1.3. The cluster's metal-rich nature and enhancement of alpha process elements suggest a possible origin involving a nearby Type II supernova explosion. The identification of variable star members, including two eclipsing binary systems, adds to its value for stellar astrophysics. Its location near the galactic plane and not far from its birthplace provides context for understanding open cluster evolution.
Did You Know?
- Its popular name comes from brighter stars forming a triangle that can resemble a flying flock of ducks or one swimming duck.
- The cluster has an estimated age of about 316 million years.
Frequently Asked Questions
What is the Wild Duck Cluster (M11)?
The Wild Duck Cluster, cataloged as Messier 11 or NGC 6705, is a dense open star cluster located in the constellation Scutum. It is widely regarded as one of the richest and most tightly packed open clusters visible to observers.
Where is M11 located in the sky?
M11 sits in the constellation Scutum (the Shield), positioned just east of the midpoint of the Scutum Star Cloud. This placement makes it a notable deep-sky target within that region of the summer sky.
Who discovered the Wild Duck Cluster and when?
Gottfried Kirch first spotted the cluster in 1681, making it one of the earlier open clusters identified by telescopic observation. Charles Messier subsequently added it to his catalog of diffuse celestial objects in 1764.
Why is M11 nicknamed the Wild Duck Cluster?
The nickname comes from the triangular arrangement of the cluster's brightest stars, which some observers see as a flock of ducks in flight while others interpret the shape as a single duck swimming. The image has stuck in popular astronomy culture ever since.
How old is the Wild Duck Cluster and what makes it stand out?
At roughly 316 million years, M11 is a relatively young open cluster that ranks among the most compact and star-rich of its kind. Its high stellar density and tight packing set it apart from many other open clusters in the catalog.
More in Messier Objects 1-24
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