
The Yridia Nebula
The Yridia Nebula was a sizable nebula located near Yridia. Its radioactive cosmic gases interfered with Starfleet sensors.
In December 2256, a Vulcan cruiser carrying Sarek was wrecked inside the nebula by the actions of logic extremist V'Latak. The USS Discovery, unable to enter the nebula as the high concentration of mycelium spores it carried would interact catastrophically with its cosmic gases, launched DSC 01 on a rescue mission. The shuttle crew was able to rescue Sarek before their craft was overwhelmed by nebular conditions. (DIS: "Lethe")
According to the revised edition of the Stellar Cartography: The Starfleet Reference Library ("History of the United Federation of Planets"), the Yridia Nebula was located in the Beta Quadrant. It was spelled "Yridian Nebula" in the reference work.