4 Aquarii or CCDM J20514-0537 AB is a variable star

Variable star

A star is classified as variable if its apparent magnitude as seen from Earth changes over time, whether the changes are due to variations in the star's actual luminosity, or to variations in the amount of the star's light that is blocked from reaching Earth...

 with a spectral type of F5V. It is a white main-sequence star with strengthened H and K lines of Ca

Calcium

Calcium is the chemical element with the symbol Ca and atomic number 20. It has an atomic mass of 40.078 amu. Calcium is a soft gray alkaline earth metal, and is the fifth-most-abundant element by mass in the Earth's crust...

 II and has neutral metal ionizations. 4 Aquarii is approximately 190 light-years from Earth

Earth

Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...

 with an absolute magnitude

Absolute magnitude

Absolute magnitude is the measure of a celestial object's intrinsic brightness. it is also the apparent magnitude a star would have if it were 32.6 light years away from Earth...

of 6.48.

4 Aquarii is a visual binary star. 4 Aquarii B is .855" (degree seconds) from 4 Aquarii and orbits around the primary every 187 years. There are two optical companions.