The scientists detected minute amounts of hydrogen in the data, as well as oxygen and sulphur, which they had never found before.
Using the European Southern Observatory’s Very Large Telescope in Chile they spotted the shape of the gases are typical indicators of a ring of gas.
Lead author Dr Boris Gaensicke, from the University of Warwick, said: “At first, we thought this was a binary star with an accretion disc formed from mass flowing between the two stars.
“However, our observations show that it is a single white dwarf with a disc around it roughly 10 times the size of our Sun, made solely of hydrogen, oxygen and sulphur.
“Such a system has never been seen before, and it was immediately clear to me that this was a unique star.”