Astronomers believe there may be mini solar systems out there - planets which orbit small, failed stars.
The suggestion is based on Spitzer telescope observations, which detail a dusty disc around a brown dwarf, a star too small to ignite its nuclear fuel.
The star, named OTS 44, is only about 15 times the mass of Jupiter.
This is much smaller than any other brown dwarf known to be surrounded by a disc of planet-building material, says US researcher Dr Kevin Luhman.
"This leads to all sorts of new questions, like 'Could life exist on such planets?' or 'What do you call a planet circling a planet-sized body? A moon or a planet?'," he added.
Previously, the smallest brown dwarf known to host a planet-forming disc was 25 to 30 times more massive than Jupiter.
The finding should ultimately help astronomers better understand how and where planets - including rocky ones resembling our own - form, the US space agency (Nasa) said in a statement.
OTS 44 was first discovered by the Gemini Observatory in Chile and then subjected to further investigation with orbiting Spitzer telescope.
The brown dwarf is located 500 light-years away in the Chameleon constellation, which can be seen near the south celestial pole.
Spitzer's speciality is in the infrared, where the detail in the dim glow of dust can be more easily discerned.
The Spitzer results are being published in The Astrophysical Journal Letters.