Answer:
Chemical composition, Temperature, Radial velocity, Size or diameter of the star, Rotation.
Explanation:
Elemental abundances are determined by analyzing the relative strengths of the absorption lines in the spectrum of a star.
The Spectral class to which the star belongs gives the information related to the temperature of the star. It is the spectral lines that determine the spectral class O B A F G K M are the spectral classes.
By measuring the wavelengths of the lines in the star's spectrum gives the radial velocity. Doppler shift is the method used to find the radial velocity.
A star can be classified as a giant or a dwarf . A giant star will have narrow width spectral lines whereas a dwarf star has wider spectral lines.
Broadening of the spectral lines will determine the star's rotation.
Molecular formula of water molecule is H₂O.
Radius of nuclei is given by formula

now we can say volume of the nuclei is given as

now the density is given as
density = mass / volume
mass of nuclei = mass of neutron + mass of protons



Now density is given as

here we know that
= 1.2 fm


So from above we can say that density of all nuclei is almost same.