From the February 2018 issue

What is the brown dwarf mechanism that allows an energy jet like the one Mayrit 1701117 has?

John Siller Commerce Township, Michigan
By | Published: February 28, 2018 | Last updated on May 18, 2023
The forming brown dwarf Mayrit 1701117 (bright orange-yellow) has a 0.7 light-year-long jet, shown in green emission from ionized sulfur in this image.
Cesar Briceno And SOAR/NOAO/AURA/NSF
Young stars not only accrete gas as they form, but also expel material in outflows that shoot from their poles. Whether lower-mass objects undergo the same process as their stellar cousins was an open question until the first substellar object (aka, brown dwarf) was found undergoing this process by Emma Whelan and collaborators. Their find was published in Nature in 2005.

Mayrit 1701117 is one of the newest examples of a young brown dwarf exhibiting a jet. In fact, it is so early in the process of forming that it is really a “proto” brown dwarf, with plenty of accretion from its surroundings left to undergo. While a lot of the details about these jets are still being studied, we do know that they are driven by rotating magnetic fields in the young brown dwarf. These magnetic fields sweep up material from the gas accreting into the brown dwarf and drive some of it toward the poles, where it ends up being ejected as a jet. Note these jets can be quite large, often several parsecs! (One parsec is 3.26 light-years.)

When these jets impact other gas along their path, they can excite it and become detectable on images or via spectroscopy, allowing us to study properties of the jet itself as well as the nearby gas.

Scott Fleming  

Archive Scientist, Space Telescope  
Science Institute, Baltimore