Which of the following does notemit light?

Options

A. Protostar
B. Sun
C. Supernova
D. White dwarf

Explanation

To determine which of the following does not emit light, let's analyze each option:

1. **Protostar**: A protostar is an early stage in the formation of a star. It forms from a cloud of gas and dust and is still in the process of gathering mass from its surrounding material. At this stage, it does not have enough energy or nuclear fusion occurring in its core to emit significant light. Therefore, a protostar does not emit light.

2. **Sun**: The Sun is a mature star that undergoes nuclear fusion in its core, producing light and heat. It definitely emits light.

3. **Supernova**: A supernova is a powerful explosion that occurs at the end of a star's life cycle. During this event, a large amount of energy is released, and it emits a tremendous amount of light, often outshining entire galaxies for a short period.

4. **White Dwarf**: A white dwarf is the remnant of a star that has exhausted its nuclear fuel. While it does not produce energy through fusion anymore, it still emits light due to the residual heat from its previous life as a star.

Based on this analysis, the answer is that the **protostar** does not emit light.

### Step-by-Step Solution:
1. Identify the options given: Protostar, Sun, Supernova, White Dwarf.
2. Understand the definition of each term.
3. Analyze the light-emitting capabilities of each option:
- Protostar: Does not emit light.
- Sun: Emits light.
- Supernova: Emits light.
- White Dwarf: Emits light.
4. Conclude that the **protostar** is the only option that does not emit light.