• Key Information

  • Stephenson 2-18

  • Type
    Red Hypergiant (or Sueprgiant) Star
  • Diameter
    1,858,838,400 miles
  • Distance
    About 19,000 light years
  • Temperature
    5,300 °F
  • Star Type(s)
    M6
  • Date of Discovery
    1990 (Charles Bruce Stephenson)
  • Other Names
    Stephenson 2 DFK 1
  • Learning Point
  • Stephenson 2-18 is thought to be one of the largest and brightest stars in our galaxy, but a lot of uncertainty exists around it, in part because of how we calculate its distance from us, which has a bearing on the brightness and size that it is as a result.
  • Project
  • Identify the largest known stars.
  • Location
  • Located in
    Scutum constellaton, within the Milky Way
  • Fun Facts
  • If this star is as big as we think it is, it would take nearly 9 hours to travel around it at the speed of light, compared to 14.5 seconds to do the same with our Sun.
  • If the star is associated with the nearby cluster, then it makes it one of the largest stars we know of, and at the same time doesn't fit into the models we currently have of stellar formation and progression.
  • Another unusual feature of the star is its temperature, which is lower than we would expect it to be.