Messier 44

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Open star cluster
Messier 44
Praesepe, the open star cluster Messier 44
Praesepe , the open star cluster Messier 44
AladinLite
Constellation cancer
Position
equinox : J2000.0
Right ascension 8 h 40.4 m
declination + 19 ° 41 ′
Appearance

classification II, 2, m (Trumpler),
d (Shapley)
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
Physical data

Redshift 112  ·  10 −6
Radial velocity 33.57 km / s
distance  577 ly
(176 pc )
diameter 22.8 years
Age 730 million years
history
Discovery time prehistoric
Catalog names
 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 .

Since Praesepe is very close to the ecliptic , planets keep moving close to this cluster or even through it. For example, in the fall of 2011, the planet Mars moved through the cluster.

Stars (selection)

Surname F. apparent
brightness 		Spectral
class 		Proper movement ( mas / a )
right ascension 		Proper movement ( mas / a )
declination 		Distance
(Lj)
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

Web links

Commons : Beehive Cluster  - collection of images, videos and audio files

Individual evidence

  1. ↑ a b c d SIMBAD
  2. ↑ a b c d e f g Messier 44 at SEDS
  3. ↑ 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 .
  4. ↑ 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 .
  5. ^ 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 .