Red Rectangular Nebula | BBC Sky at Night magazine

The red rectangular nebula, known as HD 44179, is a star similar to our Sun that is nearing the end of its life and has begun to eject its outer layers into space.

It is located 2,300 light-years from Earth in the constellation Monoceros.

This strange-looking deep sky object is known as a proto-planetary nebula.

As stars like our Sun near the end of their lives, they run out of fuel and begin to shed their outer layers.

The Red Rectangle Nebula is widely believed to be in the early stages of this process, and began ejecting material into space about 14,000 years ago.

A few thousand years into the future, the central star at the center of the nebula will be much smaller and hotter, causing the nebula to glow even more brightly, creating what astronomers know as a planetary nebula.

The term 'planetary nebula’ is a misnomer, however, as they have nothing to do with planets.

Planetary nebulae often bulge like planetary bodies, forming spherical shapes: hence their name.

But the red rectangle doesn’t form a sphere, so what’s going on?

How the red rectangle gets its shape

As can be seen with new images of the Red Rectangle Nebula, as captured using the Hubble Space Telescope, the nebula is also 'X’ shaped.

It is similar to the famous Boomerang Nebula, the coldest spot in the universe, which, when seen through new, more powerful telescopes, no longer has a boomerang shape.

According to astronomers, the formation of the Red Rectangle Nebula X is the result of an outflow of gas and dust from the central star.

Material flows from the star in two opposite directions, creating a unique pattern.

But what about the layered structure of discharges? Astronomers say these rang-like formations are caused by regular mass ejections that pulsate from the star every few hundred years.

Another reason why the Red Rectangle Nebula has a strange shape may be explained by a relatively new discovery: the star at the center is actually two stars.

This binary star system is a pair of stars that orbit each other every 10.5 months, and the gravitational interactions between the two may cause the thick dust that once surrounded them to be ejected.

This could be another explanation for the unusual shape of the Red Rectangle Nebula, as the ejecta disk affects the outflow from the central star.

discovery

The Red Rectangle Nebula was discovered in 1973 during a rocket flight to search for sources of infrared radiation in space.

This mission became known as the Air Force Cambridge Research Laboratory (AFCRL) Rocket Sky Survey.

The name Red Rectangle Nebula was coined by astronomers Martin Cohen and Mike Merrill, who captured an image of the nebula in 1973 with the 4-meter telescope at Kitt Peak National Observatory.