A lightyear is about 6 trillion miles, the distance light travels in a year. A binary star system consists of two stars very close together and orbiting each other. TMR-1C looks like it is at the end of a filament of light, as if it were flung out into the Milky Way galaxy by a young pair of binary stars. The object's age could exclude it as a planet. If it's only a few hundred thousand years old, about the same age as the star system it came from, that would indicate the object could be a planet.
Astronomers say the chances of it brown dwarf are slight.
Astronomers have detected eight possible planets outside our solar system since 1995. Before TMR-1C, none had been seen. In previous planet discoveries, astronomers based their conclusions on the behavior of surrounding stars. A planet's gravitational pull can make a star orbited by the planet wobble. If the finding is confirmed, TMR-1C will be the most important discovery Hubble has made to date.