Cannon was known as the "census taker in the sky, " and developed a stellar classification system that became the standard of the Harvard Observatory.

CNN: The historical analogs of brilliant women

Besides requiring astronomers to dream up a new mnemonic for their stellar classification, the existence of a grey area between stars and planets reveals the extent to which the processes of planetary and stellar formation are still a mystery.

ECONOMIST: Twinkle, twinkle, giant planet

Subsequent observations with an infra-red telescope, which can see things that are too cool to shine with visible light, showed that it was a very faint star so faint that it is off the bottom of astronomers' scale of stellar classification.

ECONOMIST: Twinkle, twinkle, giant planet