page_title: Beehive Cluster
section_title: Morphology and composition
hierarchical_section_title: Beehive Cluster / Morphology and composition
caption_attribution_description: Photo of comet C/2001 Q4 (NEAT) next to Messier 44 (also called Praesepe).
context_page_description: The Beehive Cluster, is an open cluster in the constellation Cancer. It is one of the nearest open clusters to Earth, containing a larger population of stars than other nearby bright open clusters. Under dark skies, the Beehive Cluster looks like a small nebulous object to the naked eye; as known since ancient times. Classical astronomer Ptolemy described it as "nebulous mass in the breast of Cancer", and it was among the first objects that Galileo studied with his
  telescope.
  Age and proper motion coincide with those of the Hyades, suggesting they may share similar origins. Both clusters also contain red giants and white dwarfs, which represent later stages of stellar evolution, along with many main sequence stars.
  Distance to M44 is often cited to be between 160 and 187 parsecs, but the revised Hipparcos parallaxes for Praesepe members and the latest infrared color-magnitude diagram favors an analogous distance of 182 pc. There are better age estimates of around 600 million years, equivalent to about 625 million years, for the Hyades. The diameter of the bright inner cluster core is about 7.0 parsecs.
context_section_description: Like many star clusters of all kinds, Praesepe has experienced mass segregation. This means that bright massive stars are concentrated in the cluster's core, while dimmer and less massive stars populate its halo (sometimes called the corona). The cluster's core radius is estimated at 3.5 parsecs (11.4 light years); its half-mass radius is about 3.9 parsecs (12.7 light years); and its  tidal radius is about 12 parsecs (39 light years). However, the tidal radius also includes many stars that are merely "passing through" and not bona fide cluster members.
  Altogether, the cluster contains at least 1000 gravitationally bound stars, for a total mass of about 500–600 Solar masses. A recent survey counts 1010 high-probability members, of which 68% are M dwarfs, 30% are Sun-like stars of spectral classes F, G, and K, and about 2% are bright stars of spectral class A. Also present are five giant stars, four of which have spectral class K0 III and the fifth G0 III.
  So far, eleven white dwarfs have been identified, representing the final evolutionary phase of the cluster's most massive stars, which originally belonged to spectral type B. Brown dwarfs, however, are extremely rare in this cluster, probably because they have been lost by tidal stripping from the halo.
  The cluster has a visual brightness of magnitude 3.7. Its brightest stars are blue-white and of magnitude 6 to 6.5. 42 Cancri is a confirmed member.
caption: Photo of comet C/2001 Q4 (NEAT) next to Messier 44
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