Our universe is host to many beautiful and fascinating objects, and we’re lucky enough to be able to view many of them using high tech instruments like the James Webb Space Telescope. A new Webb image shows a new view of the gorgeous Flame Nebula, an emission nebula located in the constellation of Orion.
This nebula is a busy stellar nursery, with many new stars being formed there. But it isn’t stars which researchers were interested in when they looked to the nebula — in this case, they were studying objects called brown dwarfs. Bigger than most planets but smaller than a star, brown dwarfs are too small to sustain fusion in their cores, so they are often referred to as failed stars.
Researchers wanted to learn about where the line is between a star and a brown dwarf. Just how much mass is necessary for an object to start fusion and become a star?
“The goal of this project was to explore the fundamental low-mass limit of the star and brown dwarf formation process. With Webb, we’re able to probe the faintest and lowest mass objects,” said lead study author Matthew De Furio of the University of Texas at Austin in a statement.
In this Webb image, three brown dwarfs are highlighted. While they may look like other baby stars, called protostars, these particular objects are exactly what the researchers were interested in.
Stars and brown dwarfs form from large clouds of material called molecular clouds, which break apart into small chunks called fragments. When these fragments are under pressure from gravity they heat up, and if there is enough material then they will become stars. But hot objects are constantly radiating, so the amount of heat they give off is important to understand where the line is between forming a star versus forming a brown dwarf.
“The cooling of these clouds is important because if you have enough internal energy, it will fight that gravity,” explained fellow researcher Michael Meyer of the University of Michigan. “If the clouds cool efficiently, they collapse and break apart.”
The researchers think that the limit between forming a star versus a brown dwarf may be at around two to three times the mass of Jupiter. But it’s hard to find these relatively small objects for them to gather data from, so they used data from the Hubble Space Telescope as well as Webb to get more information.
“It’s really difficult to do this work, looking at brown dwarfs down to even ten Jupiter masses, from the ground, especially in regions like this,” said De Furio. “And having existing Hubble data over the last 30 years or so allowed us to know that this is a really useful star-forming region to target. We needed to have Webb to be able to study this particular science topic.”
This figure shows data from both Hubble and Webb, highlighting how the two instruments can work together.
“It’s a quantum leap in our capabilities between understanding what was going on from Hubble,” said Massimo Robberto of the Space Telescope Science Institute. “Webb is really opening an entirely new realm of possibilities, understanding these objects.”
The research is published in The Astrophysical Journal Letters.
