Effects of mass accretion on the location of a low-mass RGB in the Δν − ΔΠ₁ plane. The blue star-shaped symbol corresponds to a regular 1.3 M_⊙ red giant model with solar composition. Mass accretion in the envelope of this model shifts its position horizontally to the right. The red star-shaped symbol corresponds to an accretion of 1 M_⊙ (see text), which brings the stellar mass to 2.3 M_⊙. The purple star-shaped symbol shows the location of a 2.3 M_⊙ red giant model resulting from single star evolution when it reaches the same large separation as the accretion model. The black dashed line indicates the average degenerate sequence and the gray circles correspond to RGB stars from V16, taking into account the corrections in ΔΠ₁ that were obtained in Sect. 5.2.