In celebration of the 26th anniversary of the launch of NASA’s Hubble Space Telescope, astronomers have captured an amazing image of the Bubble Nebula — an enormous, balloon-like bubble being blown into space by a hot, massive star.
This Hubble image, released to celebrate its 26th year in orbit, shows the Bubble Nebula, an emission nebula located 7,100 light-years away. This image allows us to fully appreciate the almost perfectly symmetrical shell which gives the nebula its name. The bright star visible just to the left of center is the Wolf-Rayet star SAO 20575. Image credit: NASA / ESA / Hubble Heritage Team.
The Bubble Nebula, also known as NGC 7635, LBN 548, Caldwell 11, or Sharpless 162, is a so-called emission nebula.
It was discovered in 1787 by the British astronomer and composer William Herschel.
The object lies 7,100 light-years from Earth in the constellation Cassiopeia and is approximately 7 light-years across — about 1.5 times the distance from our Sun to its nearest stellar neighbor, Alpha Centauri.
The seething star forming the nebula, the Wolf-Rayet star SAO 20575, is between 10 and 20 times the mass of the Sun.
Also known as BD +60 2522, the star is about 4 million years old, and in 10 million to 20 million years, it will likely detonate as a supernova.
Gas on SAO 20575 gets so hot that it escapes away into space as a stellar wind moving at over 4 million mph.
This outflow sweeps up the cold, interstellar gas in front of it, forming the outer edge of the bubble much like a snowplow piles up snow in front of it as it moves forward.
As the surface of the bubble’s shell expands outward, it slams into dense regions of cold gas on one side of the bubble.
This asymmetry makes the star appear dramatically off-center from the bubble, with its location in the 10 o’clock position in the Hubble view.
Dense pillars of cool hydrogen gas laced with dust appear at the upper left of the picture, and more ‘fingers’ can be seen nearly face-on, behind the translucent bubble.
The gases heated to varying temperatures emit different colors: oxygen is hot enough to emit blue light in the bubble near the star, while the cooler pillars are yellow from the combined light of hydrogen and nitrogen.
Hubble’s WFC3/UVIS instrument imaged the nebula in visible light with unprecedented clarity in February 2016. Several filters were used to sample various wavelengths.
The color results from assigning different hues to each monochromatic image associated with an individual filter. In this case, the assigned colors are: blue (F502N), green (F656N), red (F658N).
“As Hubble makes its 26th revolution around our home star, the Sun, we celebrate the event with a spectacular image of a dynamic and exciting interaction of a young star with its environment,” said John Grunsfeld, astronaut and associate administrator of Science Mission Directorate at NASA Headquarters, in Washington, D.C.
“The view of the Bubble Nebula reminds us that Hubble gives us a front-row seat to the awe-inspiring Universe we live in.”
