|Praesepe , the open star cluster Messier 44|
equinox : J2000.0
|Right ascension||8 h 40.4 m|
|declination||+ 19 ° 41 ′|
|classification||II, 2, m (Trumpler),
|Brightness (visual)||3.1 mag|
|Brightness (B-band)||3.46 likes|
|Angular expansion||95 '|
|Number of stars||350|
|Brightest star||ε Cancri, 6.3 mag|
|Redshift||112 · 10 −6|
|Radial velocity||33.57 km / s|
(176 pc )
|Age||730 million years|
|M 44 • NGC 2632 • C 0837 + 201 • OCl 507 • Mel 88 • Cr 189 • Lund 468 •|
Messier 44 , M44 or Praesepe (Latin for crib ) is an open star cluster called in astronomy , which can already be seen freely as a nebula in the evening winter and spring sky. The heavenly manger - a kind of shimmer between two stars in the constellation Cancer - was once also used for short-term weather forecasts because it becomes invisible when the clouds are cirrus .
This star cluster is the second brightest star cluster in the Messier catalog after the Pleiades and is noticeable at its position because there are no brighter stars than 4th magnitude in Cancer . It lies a little to the west of the imaginary line connecting the two stars γ Cnc and δ Cnc, which are also called Asellus Borealis and Asellus Australis (northern and southern donkey ) and serves as a manger for the two pack animals of Greek mythology.
Praesepe contains over 300 stars in the size classes between 6 mag and 12 mag. The stars are physically and dynamically very similar to the stars of the Hyades , so that a common origin for both clusters is close. Both contain main sequence stars of spectral type A and cooler, which means that the age can be estimated at around 600 million years. The distance from Praesepe, determined by the Hipparcos space telescope at 182 parsecs , is slightly greater than the distance from the Hyades. The most massive stars of Praesepe are in the center of the cluster, which has a diameter of about 11 light years. The total of over 1000 stars that are gravitationally bound to the cluster have a total mass of around 500–600 solar masses .
Proper movement ( mas / a )
|Proper movement ( mas / a )
|Epsilon Cancri (Meleph)||41||6.29||A7m||−36.3||−12.3||615|
|39 Cancri||39||6.39||K0 III||−35.6||−12.0||615|
|HD 73710||-||6.39||G9 III-IIIb||−36.2||−14.0||605|
|35 Cancri||35||6.56||G0 III||−34.6||−12.4||630|
|HD 73598||-||6.60||G8 III-IIIb||−35.1||−14.1||590|
|40 Cancri||40||6.61||A1 V||−35.3||−13.6||625|
|38 Cancri (BT Cancri)||38||6.66||F0 III||−36.9||−13.1||605|
|HD 73210||-||6.75||A5 V||−35.0||−12.8||645|
|HD 73712||-||6.78||A9 V||−38.9||−8.3||645|
|EP Cancri||-||6.78||A6 Vn||−36.0||−14.0||615|
|42 Cancri||42||6.84||A9 III||−36.2||−12.1||615|
|HD 73974||-||6.92||G8 III-IIIb||−36.9||−13.8||600|
- Amateur photos of the star cluster Praesepe, image No. 4 and 5
- Saturn, Mars, and the Beehive Cluster - Astronomy Picture of the Day from June 17, 2006 (English).
- Spektrum.de : Amateur recordings   
- Messier 44 at SEDS
- Perryman M, Brown A, Lebreton Y, Gomez A, Turon C, Cayrel de Strobel G, Mermilliod J, Robichon N, Kovalevsky J, Crifo F: The Hyades: Distance, structure, dynamics, and age . In: Astronomy & Astrophysics . 331, 1998, pp. 81-120. arxiv : astro-ph / 9707253 . bibcode : 1998A & A ... 331 ... 81P .
- van Leeuwen, F .: Parallaxes and proper motions for 20 open clusters as based on the new Hipparcos catalog , A&A , 2009, bibcode : 2009A & A ... 497..209V .
- Adams JD, Stauffer JR, Skrutskie MF, et al .: Structure of the Praesepe Star Cluster . In: Astronomical Journal . 124, 2002, pp. 1570-1584. bibcode : 2002AJ .... 124.1570A . doi : 10.1086 / 342016 .