Astron. Astrophys. 363, 947-957 (2000)

The G dwarf problem

Analysis of a new data set

Bjarne Rosenkilde Jorgensen ^*

Copenhagen University Observatory, Niels Bohr Institute, Juliane Maries vej 30, 2100 Copenhagen O, Denmark

Received 27 July 2000 / Accepted 26 September 2000

Abstract

The G dwarf metallicity distribution of a mass limited sample of stars within 40 pc and south of and for which Strömgren uvby and photometry is available is studied. Special care is taken to ensure that the sample consists of stars with a main sequence lifetime longer than the age of the Galactic disk. Furthermore, binary stars, subgiants, active stars, etc. are removed to ensure that the sample is as clean as possible. The sample was limited to the mass interval using masses determined by interpolation between theoretical evolutionary tracks. A mass interval was used as opposed to a color interval, as it is more directly comparable with theoretical models. The final sample contains 253 stars. Even though the sample shows a remarkably small low metallicity tail a new scale height weighting method was developed, and used. The resulting G dwarf distribution cannot be reconciled with the simple model for chemical evolution, in fact this dataset shows that the G dwarf problem is even larger than earlier results indicate.

Key words: Galaxy: evolution Galaxy: solar neighbourhood

* Present address : Lund Observatory, Box 43, SE-22100 Lund, Sweden (bjarne@astro.lu.se)

SIMBAD Objects

Contents

• 1. Introduction
• 2. The sample
  • 2.1. Observations
  • 2.2. Distance limit
  • 2.3. Mass derivation
  • 2.4. The mass interval
• 3. Steps towards a clean sample
  • 3.1. Accuracy & errors
  • 3.2. Binaries & subgiants
  • 3.3. Chromospheric activity
• 4. Corrections
• 5. Results
  • 5.1. Scatter estimation
• 6. Comparisons
  • 6.1. Comparison with theoretical models
• 7. Conclusion
• Acknowledgements
• References

© European Southern Observatory (ESO) 2000

Online publication: December 5, 2000
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