A moon orbits which celestial object

they move in an orbit around a celestial body, such as a planet.

Explanation:

an ion is a charged atom or molecule. it is charged because the number of electrons do not equal the number of protons in the atom or molecule. an atom can acquire a positive charge or a negative charge depending on whether the number of electrons in an atom is greater or less then the number of protons in the atom.

spectral lines lyman is one set