Most stars begin their lives in colorful style — inside giant, glowing clouds of gas and dust. One example is the Rosette Nebula, which looks like a delicate rose. It’s in Monoceros, the unicorn. The constellation is in the south-southeast at nightfall, to the lower left of much brighter Orion.
The Rosette spans more than a hundred light-years, and it’s about 10,000 times more massive than the Sun. It’s already given birth to hundreds of stars, and many more are still taking shape.
The biggest and brightest of these stars form a cluster at the center of the nebula. Energy from the stars zaps the remaining hydrogen gas around them, causing it to glow reddish pink.
The stars also produce powerful winds. The winds have cleared out a wide cavity around the stars, shutting down the process of starbirth.
But farther away, the winds actually help that process. They squeeze clumps of gas and dust, causing them to collapse. When a clump gets dense enough, its own gravity takes over, squeezing the material into a tight ball. The center of the ball gets extremely hot, igniting nuclear fusion — and giving birth to a new star.
The stars of the Rosette are only a few million years old. Eventually, the remaining gas and dust will either be incorporated into stars, or blown out into space. Over time, the stars most likely will spread out and go their own way — and the colorful Rosette will vanish.