Question

How do spectrographs help astronomers classify stars?

They determine the size of stars.
They evaluate the color of stars.
They measure the brightness of stars.
They analyze the composition of stars.

Answer 1

Answer:

They analyze the composition of stars.(I think so).

Explanation:

Hope it helps.

Answer 2

Tip- A spectrograph is a device that measures the various wavelengths of light and displays them as a spectrogram.

The composition of stars is studied using a spectograph.

Explanation: Spectrographs are used by astronomers to classify stars based on the makeup of the elements found in them.

They contain an element that absorbs all wavelengths of light and reflects the wavelengths that it does not absorb. The spectrograph and the spectrogram are used to determine this.