Collinder 140

Open Cluster Collinder 140 (= C0722-321, perhaps Lacaille II.2), in Canis Major

Right Ascension 07 : 23.9 (h:m)
Declination -32 : 12 (deg:m)
Distance 1.0 (kly)
Visual Brightness 3.5 (mag)
Apparent Dimension 42 (arc min)

Possibly discovered by Lacaille 1751-52. Discovered by Collinder 1931.

This moderately rich cluster of 30 stars, with the brightest star at 5.36 mag, lies at a distance of about 1000 light-years (according to the Sky Catalogue 2000.0). From the spectral class B3 of its bluest main sequence stars, its age was estimated at 22 million years. It is classified as of Trumpler type III 3 p (Sky Catalogue 2000.0) or III 3 m (Götz), and is receding from us at 18 km/s.

This cluster is situated about 2 degrees north of the position Lacaille gives for his "Nebulous Star Cluster" No. II.2. As his description matches well with the impression he might had have of this cluster with his 0.5-inch aperture refracting telescopes, Ronald Stoyan has proposed that Lacaille may have observed this open cluster. Later it was cataloged only by Per Collinder in 1931.

Cr 140 is a very large open cluster in the sky with its 42' diameter, almost 1 1/2 times the diameter of the Moon. It includes the wide double star Dunlop 47 (A: 5.3m, B: 7m, sep. 99").

  • Jean-Claude Mermilliod's WEBDA cluster page for Collinder 140
  • SIMBAD Data of Collinder 140
  • Publications on Collinder 140 (NASA ADS)
  • Observing Reports for Collinder 140 (IAAC Netastrocatalog)

    Hartmut Frommert
    Christine Kronberg
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    Last Modification: May 6, 2001