Messier 10

Hubble’s image of Messier 10’s dense core holds observations taken in visible and infrared light.

Distance

15,000 light-years

Apparent Magnitude

6.4

constellation

Ophiuchus

object type

Globular Cluster

Like many of the most famous objects in the sky, globular cluster Messier 10 was of little interest to its discoverer: Charles Messier, the 18th century French astronomer, catalogued over 100 galaxies and clusters, but was primarily interested in comets. Through the telescopes available at the time, comets, nebulae, globular clusters and galaxies appeared just as faint, diffuse blobs and could easily be confused for one another. Only by carefully observing their motion — or lack of it — were astronomers able to distinguish them: comets move slowly relative to the stars in the background, while other more distant astronomical objects do not move at all. Messier’s decision to catalogue all the objects that he could find and that were not comets, was a pragmatic solution which would have a huge impact on astronomy. His catalogue of just over 100 objects includes many of the most famous objects in the night sky. Messier 10, seen here in an image from the NASA/ESA Hubble Space Telescope, is one of them. Messier described it in the very first edition of his catalogue, which was published in 1774 and included the first 45 objects he identified. Messier 10 is a ball of stars that lies about 15 000 light-years from Earth, in the constellation of Ophiuchus (The Serpent Bearer). Approximately 80 light-years across, it should therefore appear about two thirds the size of the Moon in the night sky. However, its outer regions are extremely diffuse, and even the comparatively bright core is too dim to see with the naked eye. Hubble, which has no problems seeing faint objects, has observed the brightest part of the centre of the cluster in this image, a region which is about 13 light-years across. This image is made up of observations made in visible and infrared light using Hubble’s Advanced Camera for Surveys. The observations were carried out as part of a major Hubble survey of globular clusters in the Milky Way. A version of this image was entered into the Hubble’s H

ESA/Hubble & NASA

Discovered by Charles Messier in 1764, M10 is a globular cluster located in the constellation Ophiuchus. It is roughly 15,000 light-years from Earth and has an apparent magnitude of 6.4. This cluster can be spotted using a pair of binoculars and is most easily observed during July.

M10 is notable for its high population of blue stragglers — stars that appear to be far younger than their neighbors. The stars in globular clusters are thought to have formed and aged together, so they should all be roughly the same age. These anomalous, bluer stars were created either by collisions between stars or other stellar interactions. Such events are easy to imagine in densely populated globular clusters, in which up to a few million stars are tightly packed together.

Hubble’s image of M10’s dense core is made up of observations taken in visible and infrared light.

For more information about Hubble’s observations of M10, see:

Globular Cluster M10

This star chart for M10 represents the view from mid-northern latitudes for the given month and time.

Image courtesy of Stellarium

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