Astron. Astrophys. 357, 471-483 (2000)

Photometric and kinematic studies of open star clusters

II. NGC 1960 (M 36) and NGC 2194 ^*

J. Sanner ¹, M. Altmann ¹, J. Brunzendorf ² and M. Geffert <sup>1

1</sup> Sternwarte der Universität Bonn, Auf dem Hügel 71, 53121 Bonn, Germany
² Thüringer Landessternwarte Tautenburg, Sternwarte 5, 07778 Tautenburg, Germany

Received 8 December 1999 / Accepted 14 March 2000

Abstract

We present CCD photometry and proper motion studies of the two open star clusters NGC 1960 (M 36) and NGC 2194. Fitting isochrones to the colour magnitude diagrams, for NGC 1960 we found an age of Myr and a distance of roughly pc and for NGC 2194 Myr and pc, respectively. We combined membership determination by proper motions and statistical field star subtraction to derive the initial mass function of the clusters and found slopes of for NGC 1960 and for NGC 2194. Compared to other IMF studies of the intermediate mass range, these values indicate shallow mass functions.

Key words: Galaxy: open clusters and associations: individual: NGC 1960; NGC 2194 stars: luminosity function, mass function stars: Hertzsprung Russel (HR) and C-M diagrams astrometry

* partly based on data observed at the German-Spanish Astronomical Centre, Calar Alto, operated by the Max-Planck-Institute for Astronomy, Heidelberg, jointly with the Spanish National Commission for Astronomy

Send offprint requests to: Jörg Sanner (jsanner@astro.uni-bonn.de)

SIMBAD Objects

Contents

• 1. Introduction
• 2. The data and data reduction
  • 2.1. Photometry
  • 2.2. Actual cluster sizes
  • 2.3. Proper motions
  • 2.4. Colour magnitude diagrams
  • 2.5. Mass function
• 3. NGC 1960
  • 3.1. Proper motion study
  • 3.2. Colour magnitude diagram properties
  • 3.3. Initial mass function
• 4. NGC 2194
  • 4.1. Proper motion study
  • 4.2. Colour magnitude diagram properties
  • 4.3. Initial mass function
• 5. Summary and discussion
• Acknowledgements
• References

© European Southern Observatory (ESO) 2000

Online publication: June 5, 2000
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