Nowadays, all the observational characteristics are explained with a gaseous disk that is formed of material ejected from the star.
The gas and dust component of the galactic disk is called the gaseous disk.
Star formation is a complex process, which always produces a gaseous protoplanetary disk around the young star.
The latter number represents the average lifetime of gaseous disks around sun-like stars.
The cause is likely the surrounding gaseous disk which in many Be stars will appear, then disappear, possibly reforming at a later time.
Recent observations indicate that the gaseous disk of the Milky Way has a thickness of around 12000 light years-twice the previously accepted value.
The spectrum shows it to be a Be star surrounded by a hot gaseous disk, which is generating emission lines because of hydrogen recombination.
This hot, gaseous disk is about three times the radius of the star.
This emission is probably from a gaseous disk created by radiation-driven mass loss and rapid rotation of the star.
The material spread into a gaseous disk, then formed several small, extremely hot moonlets, which eventually coalesced into the single, large Moon seen today.