The unexpectedly high proportion of very-low-mass objects raises questions about the star formation process and scientists’ understanding of the “stellar initial mass function”.
Advertisement
The famous Orion Nebula spans about 24 light-years within the constellation of Orion, and is visible from Earth with the unaided eye as a fuzzy patch in Orion’s sword. In the image, the European Southern Observatory in Chile has found “A great abundance of faint brown dwarfs and isolated planetary-mass objects”.
The number of different masses in regions like the Orion Nebula can give clues to how stars form, the researchers said. The nebula is particularly bright because of the ultraviolet radiation from the multitude of hot stars being born within it.
This 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.
The observations also hint that the number of planet-sized objects might be much greater than previously thought.
With HAWK-I, the current team was able to peer through the gases that surround the Orion Nebula to examine brown dwarfs, massive objects that are bigger than gas giants but not massive enough to sustain nuclear fusion and become a star.
The Orion Nebula sits in the constellation of Orion. A new image taken by the VLT reveals never before seen low-mass objects hidden from view until now. “We now realise that the way these very low-mass objects form depends on their environment”. They don’t know why the Orion nebula has so many planets floating in space away from stars, or how they form yet.
“Our result feels to me like a glimpse into a new era of planet and star formation science”, said lead scientist Holger Drass, from the Astronomisches Institut in Germany.
Advertisement
The technology to readily observe these objects does not exist yet, but ESO’s future European Extremely Large Telescope (E-ELT). which scheduled to begin operations in 2024, will look into this as one of its goals. Most objects were found with masses around one quarter of our sun’s mass before this study; now having found an overabundance of objects with masses much lower than this yields a second maximum in the distribution of star counts with these new low-masses found. 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 with the E-ELT’.
