Correction to: Nature Astronomy https://doi.org/10.1038/s41550-020-1093-4, published online 25 May 2020.

In the version of this Article originally published, the angles φ and φs were incorrectly labelled in Fig. 1a. This has now been corrected. The original and corrected versions of the panel are shown below.

Fig. 1
figure 1

Original and Corrected.