Messier 56

This Hubble image of Messier 56 includes both visible and infrared observations.

Distance

33,000 light-years

Apparent Magnitude

8.3

constellation

Lyra

object type

Globular Cluster

The NASA/ESA Hubble Space Telescope has produced this beautiful image of the globular cluster Messier 56 (also known as M 56 or NGC 6779), which is located about 33 000 light years away from the Earth in the constellation of Lyra (The Lyre). The cluster is composed of a large number of stars, tightly bound to each other by gravity. However, this was not known when Charles Messier first observed it in January 1779. He described Messier 56 as “a nebula without stars”, like most globular clusters that he discovered — his telescope was not powerful enough to individually resolve any of the stars visible here, making it look like a fuzzy ball through his telescope’s eyepiece. We clearly see from Hubble’s image how the development of technology over the years has helped our understanding of astronomical objects. Astronomers typically infer important properties of globular clusters by looking at the light of their constituent stars. But they have to be very careful when they observe objects like Messier 56, which is located close to the Galactic plane. This region is crowded by “field-stars”, in other words, stars in the Milky Way that happen to lie in the same direction but do not belong to the cluster. These objects can contaminate the light, and hence undermine the conclusions reached by astronomers. A tool often used by scientists for studying stellar clusters is the colour-magnitude (or Hertzsprung-Russell) diagram. This chart compares the brightness and colour of stars – which in turn, tells scientists what the surface temperature of a star is. By comparing high quality observations taken with the Hubble Space Telescope with results from the standard theory of stellar evolution, astronomers can characterise the properties of a cluster. In the case of Messier 56, this includes its age, which at 13 billion years is approximately three times the age of the Sun. Furthermore, they have also been able to study the chemical

NASA & ESA

Charles Messier discovered the globular cluster M56 in 1779. The cluster is located 33,000 light-years away from Earth in the constellation Lyra. It has an apparent magnitude of 8.3 and can be observed with a small telescope most easily in August.

This beautiful Hubble image of M56 was constructed using both visible and infrared observations. Using various observations by Hubble, astronomers have been able to study the chemical composition of the cluster. M56 has relatively few elements heavier than hydrogen and helium, which is a sign that its stars were born early in the universe’s history before many of the elements in existence today were formed in significant quantities.

Astronomers have found that most of clusters with this type of chemical makeup lie along a plane in the Milky Way’s halo. This suggests that such clusters were captured from a satellite galaxy, rather than being the oldest members of the Milky Way’s globular cluster system as astronomers had previously thought.

For more information about Hubble’s observations of M56, see:

A Collection of Ancient Stars

This star chart for M56 represents the view from mid-northern latitudes for the given month and time.

Image courtesy of Stellarium

Explore Hubble's Messier Catalog

The following pages contain some of Hubble’s best images of Messier objects.

Bright green, orange, and yellow tendrils intertwined within this egg shaped nebula.

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