There is a Christmas tree in space. The nebula NGC2261, discovered about 200 years ago, has a diameter of about 1 light-year (a light-year is the distance light travels in one year, approximately 9.46 trillion kilometers) and is located 2,500 light-years away from Earth. NGC2261 is also well known as a variable nebula, featuring a unique structure resembling a Christmas tree in a fan shape. The brightness of the nebula changes as it reflects the light from stars that vary in brightness. The brightness of NGC2261 varies according to the star 'R Monocerotis' located at the apex of the fan-shaped structure. Astronomers speculate that the shadow created by a cloud of dust passing near R Monocerotis is a key factor in regulating the brightness of the nebula.
It has a liability-shaped structure.