An international team of astronomers examining data from the Next Generation Transition Survey (NGTS) has found a new brown dwarf. The object, called NGTS-28Ab, orbits its parent star every 30 hours. Brown dwarfs are objects located between planets and stars. They have 13 to 80 times the mass of Jupiter and are 0.012 to 0.076 times the mass of the Sun. While most of these objects have been discovered today, brown dwarfs orbiting other stars are rare.

Astronomers led by Beth A. Henderson of the University of Leicester (UK) studied the NGTS-28 binary system, using data from NGTS and NASA’s TESS satellite to observe exoplanet transits. They discovered a rare brown dwarf.

NGTS-28 is the main star of the system. Subsequent observations confirmed that the NGTS-28Ab object was indeed a brown dwarf. It was also observed by the South African Astronomical Observatory (SAAO).

NGTS-28Ab is slightly smaller than Jupiter in size, with a Jupiter radius of 0.95, but is 69 times larger. Its density is 98.7 g/cm³. The brown dwarf completes its orbit around its parent star at a distance of approximately 0.02 AU in 30.1 hours. The temperature of the object is approximately 863 Kelvin and its age is estimated to be at least 500 million years.

The parent star of the NGTS-28A system is about half the size and mass of the Sun. Its temperature is 3626 Kelvin and its age is approximately 7 billion years. The system’s second star, NGTS-28B, has a similar temperature but smaller size and mass. The system is approximately 404 light-years from Earth.

NGTS-28Ab has one of the shortest periods in the so-called “brown dwarf desert”, where no objects orbit very close (within 3 AU) to parent stars. NGTS-28Ab orbits one of the hottest M dwarfs in this “desert.”

This discovery has implications for understanding the “brown dwarf desert.” It was previously believed that the rarity of brown dwarfs was due to the overlap between the formation mechanisms of planets and stars. Orbiting one of the hottest M dwarfs, NGTS-28Ab offers new opportunities to study and model these parameters.

Researchers hope that further study of NGTS-28Ab and other similar objects will help increase knowledge about the formation of brown dwarfs and their role in the evolution of star systems. This could have important consequences for our understanding of the processes that lead to the formation of planets and stars.