LIFE OF A STAR What are the two main kinds of nebulae? Where in the life of a star would we find each of them? What type of star will the Sun turn into next? What will be happening inside the Sun that causes the change?

To address your questions about the life of a star, let's break it down step by step. ### 1. Two Main Kinds of Nebulae The two main kinds of nebulae are: - **Emission Nebulae**: These nebulae are clouds of ionized gas that emit light of various colors. They are often found in regions where new stars are forming, as the intense radiation from young, hot stars ionizes the surrounding gas. An example of an emission nebula is the Orion Nebula. - **Reflection Nebulae**: These nebulae do not emit their own light but instead reflect the light of nearby stars. They are typically found in regions where there are young stars, and the dust and gas surrounding them scatter the light. An example of a reflection nebula is the Pleiades. ### 2. Life Stages of a Star - **Emission Nebulae** are typically found in the **stellar formation stage** of a star's life, where new stars are being born from the gas and dust in the nebula. - **Reflection Nebulae** are also associated with the **stellar formation stage**, but they are more commonly found around young stars that are illuminating the surrounding dust and gas. ### 3. Future of the Sun The Sun is currently a main-sequence star and will eventually turn into a **red giant**. ### 4. Changes Inside the Sun As the Sun exhausts its hydrogen fuel in the core, the following changes will occur: - **Hydrogen Fusion Stops**: The core will no longer be able to fuse hydrogen into helium, leading to a decrease in pressure and an increase in temperature. - **Core Contraction**: The core will contract under gravity, causing it to heat up further. - **Hydrogen Shell Fusion**: Once the core temperature is high enough, hydrogen fusion will begin in a shell surrounding the core, leading to an increase in energy output. - **Expansion**: The outer layers of the Sun will expand significantly, transforming it into a red giant. In summary, the two main kinds of nebulae are emission and reflection nebulae, found during the stellar formation stage. The Sun will turn into a red giant as it exhausts its hydrogen fuel, leading to significant changes in its internal processes.