Sketch drawn in the companion’s orbital plane. The grey area is inside the light cylinder (LC). The thick line is the circular trajectory followed (in ~70 days) by the periastron. The thin lines are examples of orbits, approximated here by an ellipse. a) The orbital plane makes a finite angle with the star’s equatorial plane, and the periastron is lower than the light cylinder’s radius. b) The orbital plane is the same as the star’s equatorial plane, and the periastron is higher than the light cylinder’s radius. c) An example of an inclined orbital plane and a periastron higher than the light cylinder’s radius. The geometry displayed here allows for both “active” and “silent” modes. We drew the sketch accordingly to the “standard pulsar hypothesis” (hypothesis 1 in Sect. 2). Under the hypothesis 2 (“dormant pulsar”), the words “on” and “off” must be permuted.