Changes

==Properties and Structure==

==Properties and Structure==

The nebula is believed to be 2.7 [[light year]]s across and have a mass of around 5 solar masses.<ref>[http://amazingspace.org/resource_page/125/stars_stellar_evolution/type Butterfly nebula] from amazingspace.org</ref><ref name=constellation-guide/> The nebula is called a "bipolar planetary nebula" due to the to large gas/dust lobes that point in opposite directions.<ref name=constellation-guide/> There also may be two smaller lobes. There is a star situated at the centre of the nebula, where the two lobes intersect. However, it has not been detected due to the presence of a large [[dust]] lane, obscuring our view in visible light.

The nebula is believed to be 2.7 [[light year]]s across and have a mass of around 5 solar masses.<ref name=constellation-guide/><ref>[http://amazingspace.org/resource_page/125/stars_stellar_evolution/type Butterfly nebula] from amazingspace.org</ref> The nebula is called a "bipolar planetary nebula" due to the to large gas/dust lobes that point in opposite directions.<ref name=constellation-guide/> There also may be two smaller lobes. There is a star situated at the centre of the nebula, where the two lobes intersect. However, it has not been detected due to the presence of a large [[dust]] lane, obscuring our view in visible light.

===Lobes===

===Lobes===

The two lobes are composed mainly of [[dust]] and [[gas]] and believed to have temperatures of 18,000 k.<ref name=constellation-guide/> Expanding at 270 km/s, the northwestern lobe is believed to have formed 1,900 years ago. It 2013, it was found that the nebula was one of several bipolar planetary nebulae that preferred to align their long axis with the plane of the galaxy.<ref name=constellation-guide/>This only appears to be true for bipolar [[planetary nebulae]]. This is believed to be caused by an external force, such as the strong [[magnetic field]] produced by the bulge at the centre of the [[Milky Way]]. It also suggests that galactic magnetic fields have a larger effect on the galaxy than previously thought. The shape of the lobes comes from the rotation of the system.

The two lobes are composed mainly of [[dust]] and [[gas]] and believed to have temperatures of 18,000 k.<ref name=constellation-guide/> Expanding at 270 km/s, the northwestern lobe is believed to have formed 1,900 years ago. It 2013, it was found that the nebula was one of several bipolar planetary nebulae that preferred to align their long axis with the plane of the galaxy.<ref name=constellation-guide/> This only appears to be true for bipolar [[planetary nebulae]]. This is believed to be caused by an external force, such as the strong [[magnetic field]] produced by the bulge at the centre of the [[Milky Way]]. It also suggests that galactic magnetic fields have a larger effect on the galaxy than previously thought. The shape of the lobes comes from the rotation of the system.

===Central Star===

===Central Star===