Protostars illuminate the Lupus 3 molecular cloud

The Lupus 3 molecular cloud
The Lupus 3 molecular cloud

An image (CTIO/NOIRLab/DOE/NSF/AURA/ T.A. Rector (University of Alaska Anchorage/NSF’s NOIRLab). Image Processing: D. de Martin & M. Zamani (NSF’s NOIRLab)) captured by the Dark Energy Camera (DECam) at the Cerro Tololo Observatory in Chile shows the star-forming interstellar cloud cataloged as Lupus 3. Full of activity, it contains protostars that are literally breaking out of their cocoon of gas and dust such as HR 5999 and HR 6000, in the center of the image. The light of those very young stars illuminates the reflection nebula cataloged as Bernes 149. This area is in the cosmic neighborhood, so it’s observed all the time, sometimes obtaining breathtaking images of newborn stars and protostars.

The Lupus molecular complex is very large and contains at least nine molecular clouds full of hydrogen in conditions suitable for forming new stars. About 500 light-years from Earth, Lupus 3 is one of those clouds, practically in the neighborhood from an astronomical point of view. Also thanks to this relative proximity, it offers a lot to study for astronomers.

Stars are formed, in the Lupus 3 molecular cloud as in all the others, from gas. In the case of the Lupus 3 molecular cloud, there are various protostars and newborn stars of the type that belongs to the class called T Tauri. Protostars and newborn stars have just begun to emit light that illuminates gas and dust in the cloud that surrounds them. It’s a show comparable to the auroras but with a cosmic vastness in what are called reflection nebulae precisely because they reflect the starlight that strikes them.

The image captured by the DECam includes the entire Lupus 3 molecular cloud and at its center is a pair of protostars, cataloged as HR 5999 and HR 6000. They are the two oldest protostars of Lupus 3 with their ages estimated at around one million years old and already emit a blue light even if they haven’t yet completed their formation. This means that their light isn’t generated by nuclear fusion but by matter getting compressed by gravity. The consequence is a heating of the matter that generates the electromagnetic emissions we see.

The protostars HR 5999 and HR 600 illuminate the gas and dust that surround them, creating the reflection nebula cataloged as Bernes 149. If the two stars emitted enough heat to ionize the surrounding gas, they would create an emission nebula instead. When these two protostars complete their formation and enter the main sequence in which they will spend their lives, the nature of the nebula could change radically depending on the amount of heat they emit.

The DECam was used for a variety of astronomical investigations of many different types. In this case, it contributed to star formation studies by offering images that are spectacular and at the same time, very useful to understand the different phases of star formation and its consequences on the surrounding environment.

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