Sprawling across hundreds of light-years, emission nebula IC 1805 is a mix of glowing interstellar gas and dark dust clouds. Only about 7,500 light-years away, stars were born in this region whose nickname – the Heart Nebula – derives from its suggestive shape (seen here sideways).
This deep telescopic image of the nebula is very colorful, but if you could travel there and gaze across these cosmic clouds with your own eyes, are those the colors you would really see?
The short answer is no, even though the image was made with light visible to the human eye. Light from this and other glowing gas clouds surrounding hot, stars comes in very narrow bands of emission characteristic of energized atoms within the clouds.
In fact, the nebular glow is often dominated by hydrogen atoms emitting light in only a small fraction of that broad region of the spectrum that we see as the color red. Adopting an artificial color scheme commonly used for narrow band images of emission nebulae, this beautifully detailed view shows the light from sulfur atoms in red hues, with hydrogen in green, and oxygen atoms in blue.
Cosmic clouds as seen above seem to form fantastic shapes in the central regions of emission nebula IC 1805. The clouds are sculpted by stellar winds and radiation from massive stars in the nebula’s newborn star cluster, Melotte 15.
About 1.5 million years old, the cluster stars are near the center of this colorful skyscape, along with dark dust clouds in silhouette. Dominated by emission from atomic hydrogen, the telescopic view spans about 30 light-years. But wider field images reveal that IC 1805’s simpler, overall outline suggests its popular name – The Heart Nebula.
IC 1805 is located along the northern Milky Way, about 7,500 light years distant toward the constellation Cassiopeia.