In ancient Egypt the annual flood of the Nile was predicted by the rise of Sirius (the Dog Star). Sirius is one of a binary pair whose companion is a white dwarf. Orbital analysis of the pair indicates that the dwarf ’s mass is 2 x 10³⁰ kg (i.e., about one solar mass). Comparison of spectral lines emitted by the white dwarf with those emitted by the same element on Earth show a fractional frequency shift of 7 x 10^-4. Assuming this to be due to a gravitational redshift, compute the density of the white dwarf. (For comparison, the Sun’s density is 1409 kg/m³.)