Deepest Look Ever Into Orion Nebula Reveals Lots Of Tiny Tots

This spectacular image of the Orion Nebula star-formation region was obtained from multiple exposures using the HAWK-I infrared camera on ESO’s Very Large Telescope in Chile. This is the deepest view ever of this region and reveals more very faint planetary-mass objects than expected. Credit: ESO/H. Drass et al.
This spectacular image of the Orion Nebula star-formation region was obtained from multiple exposures using the HAWK-I infrared camera on ESO’s Very Large Telescope in Chile. Infrared light can penetrate the dust to show all the stars hidden within. This is the deepest view ever of this region and reveals more tiny stars and potential planets than expected. Click to supersize. Credit: ESO/H. Drass et al.

Orion Nebula in July? Sure, why not! Especially when new photos taken in infrared light of the famous star factory in the sky reveal tons of brown dwarfs and gobs of smaller, planet-mass objects.  Astronomers used the wide-field HAWK-I infrared instrument on the European Southern Observatory’s Very Large Telescope (VLT) to produce the deepest and most comprehensive view of the Orion Nebula to date.

The Orion Nebula is a little fuzzy patch faintly visible with the naked eye in Orion’s sword just below his famous 3-starred belt. Don’t run out to look just yet. Orion’s still in the daytime sky but will return to view in early August at dawn. The nebula spans about 24 light-years and it’s located 1,350 light years from Earth. At its core, a foursome of young, extremely hot stars flood the gases with ultraviolet light causing them to fluoresce in pale hues of green and pink.

This close-up in the heart of the Orion Nebula in infrared light shows just how rich the region is in infant stars. At the center is a brilliant quadruple star called the Trapezium. UV light from the stars illuminates the nebula. Credit: ESO / H. Drass et. al
This close-up in the heart of the Orion Nebula in infrared light shows just how rich the region is in infant stars. At the center is a brilliant little cluster called the Trapezium. UV light from the stars, primarily the massive Theta-1 Orionis C (star at right side of the Trapezium), illuminates the nebula. Theta-1 is more than 250,000 times more luminous than the sun! Credit: ESO / H. Drass et. al

The relative proximity of the Orion Nebula makes it an ideal test bed to better understand the process and history of star formation, and to determine how many stars and planets of different masses form. Just as our environment helps shape who we are, the environment of the Orion Nebula determines what kind and how many different types of star form. The Hubble Space Telescope has revealed more than 3,000 stars within the cloud, each formed by the gravitational collapse of smaller clouds of gas and dust within the nebula.

This new photo has astronomers excited caused excitement because it reveals a unexpected wealth of very-low-mass objects. In other words, brown dwarfs and planets. This suggests that the Orion Nebula may be forming proportionally far more low-mass objects than closer and less active star formation regions.  Astronomers count up how many objects of different masses form in regions like the Orion Nebula to try to understand the star-formation process. Before this research the greatest number of objects were found with masses of about one quarter that of our Sun. Now we suspect that the number of planet-sized objects may be far greater than previously thought.

most brown dwarfs are only slightly larger than Jupiter (10–15%) but up to 80 times heavier due to greater density. (Note: The Sun is not to scale and would be larger.) Credit: NASA/JPL-Caltech/UCB
Most brown dwarfs are only slightly larger than Jupiter (10–15%) but up to 80 times heavier due to greater density. (Note: The Sun is not to scale and would be larger.) Brown dwarfs are between 13 and 75 times more massive than Jupiter, but unlike red dwarfs and larger stars, they’re not massive enough to “burn” hydrogen in their cores through nuclear fusion. All are extremely faint. Credit: NASA/JPL-Caltech/UCB

These observations also hint that the number of planet-sized objects might be far greater than previously thought. I wouldn’t be surprised. The most common stars in the universe, called red dwarfs, are also the coolest and smallest (outside of exotics like white dwarfs and neutron stars). They have masses between 7.5% and 50% that of our sun and burn their energy reserves so slowly, they’ll be around for trillions of years, far longer than the current age of the universe. Massive stars like massive animals take a lot more stuff to build and exceedingly rare compared to the zillions of microscopic bacteria found on nearly every surface around us. So why not even more brown dwarfs? More planets? Indeed why not.

“Our result feels to me like a glimpse into a new era of planet and star formation science,” said lead scientist Holger Drass of the Orion project. The huge number of free-floating planets at our current observational limit is giving me hope that we will discover a wealth of smaller Earth-sized planets.”