A team including MIT and Harvard-Smithsonian astronomers has observed a small star drawing material from a brown dwarf companion, a process that could continue for billions of years.
The findings were published Oct. 5 in Nature Astronomy. The paper's abstract describes direct observations of stable mass transfer in the system ZTF J0440+2325, where the two objects orbit each other every 87 minutes.
A brown dwarf has too little mass to sustain the hydrogen fusion that powers a star. In this pair, the companion is transferring material to an M dwarf, a small, relatively cool star.
According to MIT's account of the study, the system is about 300 light-years away. The brown dwarf has roughly 25 times Jupiter's mass, while the receiving star has about 85 times Jupiter's mass.
The researchers examined changes in brightness and the star's motion, then used simulations to interpret the pair. Material from the brown dwarf forms a stream toward the star and heats the area where it reaches the surface.
The study also identifies a second system, ZTF J1444+4820, as a strong candidate for a similar process. Its abstract distinguishes that candidate from the directly observed mass transfer in ZTF J0440+2325.