The brightness of a reflection nebula lit by a blue star born in a dark nebula | sorae Portal site to the universe

The “interstellar space” that spreads between stars is not an empty vacuum, but contains interstellar gas and interstellar dust. These gases and dust, collectively known as the interstellar medium, are not evenly distributed, and regions denser than the surroundings are called “dark clouds.”

As the name suggests, dark nebulae themselves cannot be seen with visible light that humans can detect. Observations using infrared rays and radio waves, which have longer wavelengths than visible light, have revealed that dark nebulae contain various molecules. Therefore, dark nebulae are also called “molecular clouds”.


This image shows the dark nebula “Lupus 3” about 500 light years away in the direction of “Lupus” in the southern sky.

Two blue stars (HR 5999 and HR 6000) shine in the center of constellation 3. Both stars illuminate the gas and dust brightly in blue, called Reflection Nebula Bernes 149, and together with 3 Lupus creates a spectacular scene. A reflection nebula, as the name suggests, is a nebula that shines by reflecting the light of a star rather than emitting its own light.

The substances (molecules) that are in the constellation 3 of lepus will be the materials that create new stars. HR 5999 and HR 6000 also originated and grew within Libra 3. Both stars are still a million years old, and they are pre-main sequence stars of a type known as “Taurus T-type stars,” which are pre-stage main sequence stars like the Sun. Despite their brightness, the two stars do not still shine from nuclear fusion energy as the sun does, but from contracting and heating under their own gravity.

During the formation of a T Tauri star, a powerful stellar wind is ejected which blows away gas and dust. The Burns 149 was created from that residue. Thus, 3 Lupus is an active star-forming region, and provides information on the formation of stars such as protostars.

This image is from the wide-field Dark Energy Camera (DECam) mounted on the Victor M. Blanco 4 meter telescope at the Cerro Tololo Inter-American Observatory, NOIRLab.

Lupus 3 is one of at least nine dark nebulae that form a complex of molecular clouds, and is said to spread over a range equivalent to the apparent diameter of 24 full moons. By combining DECam’s wide field of view with the light-gathering ability of the Blanco 4-metre telescope, a sharp, high-resolution image of constellation 3 was obtained.

Finally, here’s a zoomed in video of Lupus 3 and Barnes 149.


  • Image Credit: CTIO/NOIRLab/DOE/NSF/AURA/ TA Rector (University of Alaska Anchorage/NOIRLab NSF); Processing: D. de Martin & M. Zamani (NSF’s NOIRLab)
  • Video Credit: NOIRLabAstro
  • NOIRLab – Radiant Protostars and Shadowy Clouds Clash in Stellar Nursery

Sentence/Tetsuro Yoshida