Comparison of synthetic and observed photometry for HIP 91599. The top panel displays the spectral energy distribution. The colored data points are filter-averaged fluxes that were converted from observed magnitudes. The dashed horizontal lines depict the full widths at 10% of the maximum of the filter transmissions, while the solid gray line represents the best fitting model (spectral resolution of 6 Å). In order to reduce the steep slope of the SED the flux is multiplied by the wavelength to the power of three. Bottom panel: residuals, χ: differences between synthetic and observed magnitudes divided by the corresponding uncertainties. The photometric systems have the following color code: UV magnitudes from the TD1 satellite (violet; Nandy et al. 1978) labeled with central wavelengths, optical magnitudes from Tycho2 (Høg et al. 2000), HIPPARCOS (van Leeuwen 2007), Gaia (blue Gaia Collaboration 2020), and Mermilliod (2006); IR photometry from 2MASS (red Cutri et al. 2003) and DENIS (yellow Denis 2005). Right hand panel: color indices in the Johnson (cyan) and Geneva (red) systems (Mermilliod 2006; Rufener 1988).