I am pleased to present to you an amazing celestial object: Sh2-119, a emission nebula located in the constellation of Cygnus, about 2,200 light-years away from Earth. Sh2-119 also known as the Clamshell nebula. Upon closer inspection, we can see that the nebula takes the shape of an ellipsoid, surrounding a star designated as 68 Cygnus, which is classified as an O7.5IIIn-type star. This star has a mass of approximately 26 times that of the Sun and a temperature of around 34,000 degrees Kelvin.
The initial hypothesis about the origin of the Sh2-119 nebula suggested that it was a byproduct of the stellar wind emitted by the star 68 Cygnus. However, more recent astronomical studies have shown that Sh2-119 is actually a Stremgren sphere, a spherical shell of ionized hydrogen surrounding a young O or B type star. The theoretical basis for this type of nebular structure was laid by Bengt Stremgren in 1937. Therefore, the source of ionization in Sh2-119, which causes gases to emit light with certain wavelengths, is simply the star 68 Cygnus itself. Like many other nebulae, Sh2-119 serves as a reminder of the immense power and grandeur of the universe.
Below is an entry in Sharpless's catalog about Sh2-119.
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