IRFM T calibrations for cluster and field giants in the Vilnius, Geneva, RI and DDO photometric systems^*

¹ Seminario Permanente de Astronomía y Ciencias Espaciales, Universidad Nacional Mayor de San Marcos, Ciudad Universitaria, Facultad de Ciencias Físicas, Av. Venezuela s/n, Lima 1, Perú
² Department of Astronomy, The University of Texas at Austin, RLM 15.202A, TX 78712-1083, USA
³ Department of Astronomy, California Institute of Technology, MC 105–24, Pasadena, CA 91125, USA

Corresponding author: I. Ramírez, ivan@astro.as.utexas.edu

Received: 2 May 2003
Accepted: 19 November 2003

Abstract

Based on a large sample of disk and halo giant stars for which accurate effective temperatures derived through the InfraRed Flux Method (IRFM) exist, a calibration of the temperature scale in the Vilnius, Geneva, and DDO photometric systems is performed. We provide calibration formulae for the metallicity-dependent vs. color relations as well as grids of intrinsic colors and compare them with other calibrations. Photometry, atmospheric parameters and reddening corrections for the stars of the sample have been updated with respect to the original sources to reduce the dispersion of the fits. Application of our results to Arcturus leads to an effective temperature in excellent agreement with the value derived from its angular diameter and integrated flux. The effects of gravity on these vs. color relations are also explored by taking into account our previous results for dwarf stars.