|System:||Sif - All bodies|
|Distance to Sol:||186.91 ly|
|Spectral Class:||TTS7 VA - Not Scoopable|
|Luminosity Class:||VA - Main-sequence star (dwarf)|
|Age:||98 Million years|
|Surface Temperature:||2,449 K|
Class Y dwarfs are the coolest of the brown dwarfs. Surface temperatures are less than 700 K, and are effectively very large gas giant planets, with some stellar properties.
The term dwarf star refers to a variety of distinct classes of stars. The term was originally coined in 1906 when the Danish astronomer Ejnar Hertzsprung noticed that the reddest stars - classified as K and M in the Harvard scheme - could be divided into two distinct groups. They are either much brighter than the Sun, or much fainter. To distinguish these groups, he called them "giant" and "dwarf" stars, the dwarf stars being fainter and the giants being brighter than the sun.