The star you are referring to is called Sigma Octantis, also known as Polaris Australis or South Pole Star. It is the southern hemisphere's equivalent of the North Star, Polaris, which is visible only in the Northern Hemisphere. Sigma Octantis serves as a reference point for navigation in the southern sky, similar to how Polaris helps navigators in the northern sky. However, it is important to note that Sigma Octantis is not as bright or easily recognizable as Polaris due to its relative faintness.