SED of IRS 3–IRS 7. Filled circles are the data points and the triangles are lower and upper limits where errors are generally smaller than the data points. The solid black line indicates the best-fitting model, and the grey lines show all models that also fit the data satisfying the χ2 −χ2 best < 3 per data point criteria. The dashed line shows the SED of the assumed stellar photosphere in the best-fitting model.