Distance, Physical Properties, and Deep Imaging of PGCC G103.36−17.11 and PLCKECC G103.18−17.09 (LBN 477)

PGCC G103.36−17.11 (Planck Catalogue of Galactic Cold Clumps) and PLCKECC G103.18−17.09 (Planck Early Cold Cores catalogue), are two condensations, 10.1′ (1.2 pc) apart, within a single cloud at Galactic latitude b ≈ −17° that coincides with the reflection nebula LBN 477 (Lynds' Catalogue of Bright Nebulae). The cloud, defined as the region where the Planck 857 GHz dust emission exceeds 25% of its peak excess over the background, at an estimated distance of ≈ 410 pc, has a mass of ≈107 solar masses (M⊙; 78–126 M⊙ for thresholds of 40–15%) within an equivalent radius of ≈1.4 pc. The eastern condensation (PGCC G103.36−17.11, which contains IRAS 23071+4135, a far-infrared source detected by the Infrared Astronomical Satellite, IRAS) and the western condensation (PLCKECC G103.18−17.09) contain ≈15 and ≈11 M⊙, respectively. With these masses the cloud is at most marginally bound, although the uncertainties in mass and linewidth do not allow a firm classification. Deep luminance–red–green–blue (LRGB) imaging (27.5 h) detects scattered light down to 3σ surface-brightness limits of 25.7–26.8 mag arcsec−2 per 1′ bin. The scattered light correlates tightly with the dust emission (r ≈ 0.9), and at high dust column density its colour becomes redder and its brightness increases less steeply than the column, as expected for a translucent cloud illuminated by the general interstellar radiation field.