Let's trace the life cycle of a 'low-mass star' like our Sun:
1. **Nebula:** It begins as a giant cloud of gas and dust, called a nebula. Gravity pulls this material together.
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2. **Protostar:** As the gas and dust clump together, it gets hotter and denser, forming a protostar. It's not a 'true' star yet because nuclear fusion hasn't started.
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3. **Main-Sequence Star:** When the core becomes hot and dense enough, nuclear fusion begins (hydrogen atoms combine to form helium, releasing huge energy). The star shines brightly and spends most of its life in this stable phase, like our Sun.
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4. **Red Giant:** After billions of years, the hydrogen fuel in the core runs out. The core shrinks, but the outer layers expand and cool, making the star much larger and redder. It's now a Red Giant.
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5. **Planetary Nebula:** The outer layers of the Red Giant drift away into space, forming a beautiful, expanding cloud of gas and dust called a planetary nebula.
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6. **White Dwarf:** The hot, dense core that is left behind after the outer layers are shed is called a White Dwarf. It slowly cools down over billions of years, no longer undergoing fusion.
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7. **Black Dwarf:** Eventually, after an extremely long time, the White Dwarf cools completely and stops emitting light, becoming a theoretical Black Dwarf. This is the final stage for low-mass stars.