The researchers also detected metal pollution in the form of sodium, lithium, potassium and possibly carbon.

The lithium line shows Zeeman splitting, which indicates that WD J2147–4035 is a magnetic white dwarf.

The magnetism can lead to inhomogeneous brightness distribution and the TESS light curve shows that the white dwarf has a rotation period of around 13 hours.

[1] Cold white dwarfs are often strongly affected by collision induced absorption (CIA) of hydrogen.

WD J2147–4035 is however very red (r-z=2.29 mag) which is seen as evidence that it only has a low hydrogen to helium ratio, resulting in very mild CIA and therefore giving it the distinct orange color.