Artikel zu K1 M44: A Beehive of Stars K2 Praesepe: A Pair of Colliding Star Clusters? K3 Messier 44 by SDSS K4

August 3, 1998

Explanation: M44 is a prominent open cluster of stars. Nicknamed Praesepe and "The Beehive", it is one of the few open clusters. M44 was thought to be a nebula until Galileo used an early telescope to resolve the cluster's bright blue stars. These stars are visible in the above image. M44, which is thought to have formed about 400 million years ago, is larger and older than most other open clusters. The Beehive Cluster lies about 580 light-years away, and spans about 10 light-years across. When viewed with a powerful telescope, hundreds of stars become visible.

The Beehive Cluster is visible to the naked eye as a hazy patch of light near the center of Cancer. Courtesy Sven Kohle and Till Credner.

One of the prettiest sights in the night sky may be hiding a destructive secret. The Beehive (M44), also known as Praesepe, is an open cluster of several hundred stars located 570 light-years away in the constellation Cancer. However, according to a team led by Karen Holland and Richard Jameson (University of Leicester), the 800-million-year-old Beehive actually consists of two colliding star clusters.

By analyzing the X-ray brightness of the Beehive's individual members, the researchers identified a concentration of older stars (which have weaker emissions). Yet stellar mingling should have evened out any such segregations long ago. In addition, a close examination of gravitational interactions within the cluster revealed that it is unstable. The stars are moving so quickly that the Beehive will disintegrate within only 10 million years.

According to Jameson and Holland, the obvious explanation for these peculiar properties is that the Beehive contains two open star clusters in the process of colliding. Details will appear later this year in the Monthly Notices of the Royal Astronomical Society.

Messier 44, also know as Praesepe and the beehive clusters, is a famous cluster of stars in our own Milky Way galaxy. It is at a distance of about 180 parsecs in the constellation Cancer. The stars all formed at nearly the same time, about 800 million years ago. The cluster includes many different types of stars, including main sequence stars, red giants, and white dwarfs, and is often studied by astronomers. The Messier catalog was compiled by Charles Messier as an aid in finding comets - most of the objects in his catalog are faint and nebulous in appearance and easily mistaken for comets. It is unclear why he included this star cluster as object 44 since it is bright and was already well known.   (Caption by Steve Kent)

H. Heintzmann

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