Published: Wed, August 08, 2018
Sci-tech | By April Francis

Brown dwarf or massive exoplanet detected with powerful magnetic field

Brown dwarf or massive exoplanet detected with powerful magnetic field

The rogue body is almost large enough to be considered a gas giant planet and it offers researchers the opportunity to study these massive objects, shedding light on their magnetic realities.

At 200 million years old and approximately 20 light-years from Earth, SIMP0136 has a surface temperature of about 1,500 degrees Fahrenheit (825 degrees Celsius). Brown dwarfs, hard to categorise, are too huge to be classified as planets and not big enough to be classified as stars.

The unusual object, called SIMP J01365663+0933473, has a magnetic field which is more than 200 times stronger than the magnetic field field of Jupiter, according to the study published in The Astrophysical Journal Supplement Series.

The Karl G. Jansky Very Large Array radio telescope has detected emissions, presumably from an aurora, generated by an unusual body 12 times more massive than Jupiter and generating a magnetic field 200 times more intense that is flying through space on its own 20 light years from Earth. The first brown dwarf was discovered in 1995, although they were first theorized in the 1960s. Such cases are rare as only a few rogue planets have been found before but it is theorized that many similar planets may in fact exist.

"This particular object is exciting because studying its magnetic dynamo mechanisms can give us new insights on how the same type of mechanisms can operate in extrasolar planets", said [Arizona State University's Melodie] Kao. It is the radio signature of these auroras that allowed the researchers to detect these objects.

Auroras on Earth are created when charged particles from the Sun interact with Earth's magnetic field.

SIMP's magnetic field is over 200 times that of Jupiter's, notes the report.

The surprising find is peculiar because it could be a planet or a brown dwarf. At its size, it's right between the size of a planet and a failed star, so scientists will need to study it further to determine exactly what it is.

Brown dwarf masses are notoriously hard to measure, and at the time, SIMP0136 was thought to be an old and much more massive brown dwarf.

The unusually strong magnetic field "presents huge challenges to our understanding of the dynamo mechanism that produces the magnetic fields in brown dwarfs and exoplanets and helps drive the auroras we see", said Caltech's Gregg Hallinan. This finding is the first radio telescope finding of an object the mass of a planet found outside the Solar System.

The boundary often used to distinguish a massive gas giant plant from a brown dwarf is the "deuterium-burning limit" - the mass below whichdeuterium stops being fused in the objects core.

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