The Rosette Nebula is a cloud of dust containing enough gas and dust to make about 10,000 stars like our Sun. In the centre of the nebula is a cluster of hot, bright young stars. These are warming up the surrounding gas and dust, making it appear bluer. The small, bright white regions are cocoons of dust in which huge stars are currently being born. These “protostars”, each one of which will probably become a star up to ten times more massive than the Sun, are heating up the surrounding gas and dust and making it clow brighter. The smaller, redder dots on the left side and near the centre of the image also contain protostars, but these are smaller, and will go on to form stars much like our Sun. Just as the centre of the nebula contains bright young stars, in a few tens or hundreds of millions of years these stars will have died, but the protostars will have evolved into fully-fledged stars in their own right. In this way, the star formation will move outwards through the nebula.
The Soul Nebula is an emission nebula located in the constellation Cassiopeia. It forms a famous pair known as the Heart and Soul with the neighbouring Heart Nebula (IC 1805). The Soul Nebula is sometimes also known as the Embryo Nebula or IC 1848, which is a designation used for the open star cluster embedded within the nebula. The Heart and Soul Nebulae complex spans an area about 300 light years across and is a vast star-forming region illuminated by the light of the young stars surrounded by star-forming clouds of dust and gas. The two large clouds are separated by only 2.5 degrees and physically connected by a bridge of gas. The stars in the region are less than a few million years old and are only beginning their life. For comparison, our Sun has been around for almost 5 billion years.
