What is the primary reason for the lack of ongoing star formation in mature elliptical galaxies?
Answer
A significant lack of the cold gas needed to fuel new star birth
The lack of ongoing star formation is directly attributed to the absence of cold, molecular gas and dust, which is the primary fuel source for making new stars.

Related Questions
What are the three main galaxy classifications astronomers usually discuss based on visual appearance?Which characteristic stellar population overwhelmingly dominates elliptical galaxies?What visual feature do elliptical galaxies lack compared to spiral galaxies?What is the primary reason for the lack of ongoing star formation in mature elliptical galaxies?How do stars generally orbit the galactic center in an elliptical galaxy?What process describes the external removal of hot gas from a galaxy moving through a dense galaxy cluster environment?Which type of elliptical galaxy is described as the smallest and most numerous in the universe?What event often consumes the cold fuel rapidly during the merger that forms massive elliptical galaxies?What is the nature of the gas that elliptical galaxies typically possess, as opposed to the cold gas they lack?What characteristic hue results from a galaxy where massive, short-lived blue stars have died off?What pathway is widely believed to create the most massive elliptical galaxies?