Positions of S stars and infrared excess sources in the innermost (3.0′′ × 3.0′′) of the Galactic centre according to Eckart et al. (2013). The colours denote the colour (K_s − L′) according to the colour scale to the right. A colour (K_s − L′) for ordinary, B-type S stars (e.g. S2 as a prototype) is expected to be ~0.4 (with line-of-sight extinction). The position of the DSO and S stars was calculated for 2012.0 epoch according to the orbital solutions in Valencia-S. et al. (2015) and Gillessen et al. (2009), respectively.