Publications of the Astronomical Society of Australia

Research Article

The Emergent Flux and Effective Temperature of δ Canis Majoris

J. Davisa1 c1, A. J. Bootha2, M. J. Irelanda3, A. P. Jacoba1, J. R. Northa1, S. M. Owensa1, J. G. Robertsona1, W. J. Tangoa1 and P. G. Tuthilla1

a1 School of Physics, University of Sydney, Sydney NSW 2006, Australia

a2 Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA

a3 Planetary Science, MS 150-21, Caltech, 1200 E. California Blvd, Pasadena, CA 91125, USA


New angular diameter determinations for the bright southern F8 supergiant δ CMa enable the bolometric emergent flux and effective temperature of the star to be determined with improved accuracy. The spectral flux distribution and bolometric flux have been determined from published photometry and spectrophotometry and combined with the angular diameter to derive the bolometric emergent flux ℱ = (6.50 ± 0.24) × 107 Wm−2 and the effective temperature T eff = 5818 ± 53 K. The new value for the effective temperature is compared with previous interferometric and infrared flux method determinations. The accuracy of the effective temperature is now limited by the uncertainty in the bolometric flux rather than by the uncertainty in the angular diameter.

(Received May 17 2007)

(Accepted September 10 2007)


  • stars: atmospheres;
  • stars: fundamental parameters;
  • stars: individual (δ CMa);
  • techniques: interferometric


c1 Corresponding author. Email: