A revised DDO abundance calibration for population I red giants

A. E. Piatti, J. J. Clariá, D. Minniti

Research output: Contribution to journalArticlepeer-review

17 Citations (Scopus)


Several arguments that justify establishing a revised abundance calibration for DDO photometry of population I red giants are presented. The components of the blanketing vector in the DDO C(45-48) vs C(42-45) diagram are determined for late-type dwarfs and giants. We have redefined the DDO cyanogen anomaly and calibrated it against metallicity. The sample of field giants now available with abundances derived from high dispersion spectroscopy is substantially larger than previously available, leading to a more accurate abundance calibration. Iso-abundance lines in the C(41-42) vs C(42-45) diagram have been determined for population IG and K giants and an iterative method for deriving abundances of these stars is described. We show that the new DDO abundances are in very good agreement with those derived from high dispersion spectroscopy. The new method improves by about 0.1 dex the DDO abundances derived for early G and/or late K giants, with respect to the δCN method of Janes (1975).

Original languageEnglish
Pages (from-to)145-165
Number of pages21
JournalJournal of Astrophysics and Astronomy
Issue number3-4
Publication statusPublished - 1 Dec 1993


  • Technique: photometry
  • stars: general
  • stars: late-type
  • stars: population I

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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