Normalised HARPS spectrum of CPD −62° 2124 (grey solid line) in the Hα spectral region. The synthetic photospheric CPD −62° 2124 spectrum is also shown (black solid line), together with the HARPSpol spectrum of the He-strong stars CPD −57° 3509 (blue line, Przybilla et al. 2016) and that of HD 37479 (red line, e.g. Oksala et al. 2012). The spectrum of HD 37479 was obtained within the context of the IACOB project² (Simón-Díaz et al. 2011, 2015). The narrow central emission in the CPD −62° 2124 spectrum is of nebular origin.