UX Orionis is a

variable star A variable star is a star whose brightness as seen from Earth (its apparent magnitude) changes systematically with time. This variation may be caused by a change in emitted light or by something partly blocking the light, so variable stars are ...

in the constellation of

Orion Orion may refer to: Common meanings * Orion (constellation), named after the mythical hunter * Orion (mythology), a hunter in Greek mythology Arts and media Fictional entities Characters and species * Orion (character), a DC Comics c ...

. It is a Herbig Ae star, located about 1000

light years A light-year, alternatively spelled light year (ly or lyr), is a unit of length used to express astronomical distances and is equal to exactly , which is approximately 9.46 trillion km or 5.88 trillion mi. As defined by the International Astro ...

from the Earth. At its brightest it is a magnitude 9.5 object, so it is too faint to be seen with the naked eye. UX Orionis is the prototype of the UX Orionis class of variable stars (often called "UXors"), which are young stellar objects that exhibit large (greater than 2.8 magnitude), irregular changes in visual band brightness. UX Orionis was discovered by

Henrietta Swan Leavitt Henrietta Swan Leavitt (; July 4, 1868 – December 12, 1921) was an American astronomer. Her discovery of how to effectively measure vast distances to remote galaxies led to a shift in the understanding of the scale and nature of the universe. ...

. UX Orionis is surrounded by a

circumstellar disk A Circumstellar disc (or circumstellar disk) is a torus, pancake or ring-shaped accretion disk of matter composed of gas, dust, planetesimals, asteroids, or collision fragments in orbit around a star. Around the youngest stars, they are the res ...

, and the star's photometric variability appears to be caused by episodes during which the star is obscured by dusty material within the circumstellar disk.

References

{{Stars of Orion Orion (constellation) Herbig Ae/Be stars 293782 23602 J05042998-0347142 Orionis, UX