Spectral energy distribution of Hen 3-1379. The different symbols indicate photometric measurements from various sources. Error bars are not showed for clarity but they are usually comparable to the symbol size. At 70 μm and 160 μm, the two measurements refer to the inner unresolved nebula and to the larger ring, both well separated on the PACS images. The SED is fitted with the sum (red continuous curve) of two modified black-body curves with dust temperatures T_d = 182 K and T_d = 63 K (dashed blue curves).