A brown dwarf, otherwise known as a ‘failed star’, are formed when stars cannot gather enough mass to trigger nuclear reactions, which would convert their cores from hydrogen into helium.
“We seem to have come across a speed limit on the rotation of brown dwarfs,” said Megan Tannock, the Western University physics and astronomy graduate student who led the discovery.
“Despite extensive searches, by our own team and others, no brown dwarfs have been found to rotate any faster. In fact, faster spins may lead to a brown dwarf tearing itself apart.”
These three celestial objects (scientifically designated as 2MASS J04070752+1546457, 2MASS J12195156+3128497, and 2MASSJ03480772−6022270) are revolving at an astonishing 350,000 kilometres per hour.
This is ten times faster than normal, when it would usually take ten hours for a dwarf to spin on its axis, and 30 per cent faster than the fastest spin previously recorded.
The record-breaking objects were discovered by astronomers at Western University in Canada, using Nasa’s Spitzer Space Telescope. Their findings were then confirmed using the Gemini North telescope in Hawai‘i and Carnegie Institution for Science’s Magellan Baade telescope in Chile.
In order to measure the dwarfs’ spin, the scientists monitored alterations in the light given off – caused by the Doppler effect, where light is moved up or down the colour spectrum based on speed – and matched that to their movements using a computer model.
“Brown dwarfs, like planets with atmospheres, can have large weather storms that affect their visible brightness,” explained Tannock and Western University astronomer Stanimir Metchev.
“The observed brightness variations show how frequently the same storms are seen as the object spins, which reveals the brown dwarf’s spin period.”
The scientists’ findings will be published in an upcoming issue of the Astronomical Journal, with a preprint currently available now.