Colors/Magnitudes

We provide colors and magnitudes computed from our synthetic spectra and calibrated to zero magnitudes in all bands for Vega, according to Hayes (1985, Proc IAU Symposium Number 11, 'Calibration of Fundamental Stellar Quantities', p. 225) and Hayes & Latham (1975, ApJ 197, 593) for the optical, and Mountain et al. (1985, A&A, 151, 399) for the near-infrared. Reddening is treated according to interstellar reddening curves by Cardelli et al. (1989, ApJ, 345, 245). The band systems currently available are:
  1. Vilnius UBV system
  2. Cousins BVRI system
  3. Bessell UBVRI (1990) + JHKLLLM (1988) system
  4. Johnson RIJKLLLMN system
  5. Johnson-Mould UBVRIJHK system
  6. Bessell 1988 JHKL filters transformed to CIT system
  7. CIT JHK + Cousin RI + Bessell's UBVJLLM (1988-90)
  8. Wing 8-color system
  9. Caltech system (for Gl229B)
  10. HST WFPC2/NICMOS Flight & Ground systems
  11. FeH by Eduardo Hardi
  12. Landolt UBVRI system (AJ 104, 340, 1992)
  13. DENIS system
  14. CADIS system
  15. UKIRT system + VRI Bessell 90 with 7600A telluric abs.
  16. ISO system + UKIRT K
  17. ESO I,Z system
  18. Carter JK system
  19. Bessell Johnson-Glass J,K system (Pascal Fouquet, ESO)
  20. UKIRT J,K system (Pascal Fouquet, ESO) + I Cousins
  21. EROS B,R system
  22. SIRTF IRAC camera UBRI system
  23. Tautenburg various filters
  24. Sloan RZ filters + ACS CCD + Bessell VRI (1990)
The color files can usually be found on our anonymous ftp server in the subdirectories hosting each model atmosphere grid. They are named typically: colmag.grid_name.filter_designation. The header of each colmag file describes again its content. These files give magnitudes at the stellar surface (m_atm) for each model in the parameter space [Teff,logg] of the grid. Absolute magnitudes (M_m) are obtained from the stellar radius (R_star_symbol) using this relation:

M_m (at 10 pc) = m_atm - 5logR_star_symbol(pc) + 5

Our grids usually extend on a large parameter range allowing for an interpolation of the colmag file along theoretical Teff-logg relations of isochrones to obtain absolute magnitudes as a function of mass.