Posted on 06/16/2003 11:49:24 PM PDT by petuniasevan
Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
Explanation: It's the bubble versus the cloud. NGC 7635, the Bubble Nebula, is being pushed out by the stellar wind of massive central star BD+602522. Next door, though, lives a giant molecular cloud, visible above to the lower right. At this place in space, an irresistible force meets an immovable object in an interesting way. The cloud is able to contain the expansion of the bubble gas, but gets blasted by the hot radiation from the bubble's central star. The radiation heats up dense regions of the molecular cloud causing it to glow. The Bubble Nebula, pictured above as a color negative to help bring up contrast, is about 10 light-years across and part of a much larger complex of stars and shells. The Bubble Nebula can be seen with a small telescope towards the constellation of Cassiopeia.
NGC 7635
The Bubble Nebula
Planetary Nebula
Size: 15' x 8'
Constellation: Cassiopeia
RA: 23h 20m 42s
Dec: +61 11' 00"
It is NOT easy to see this nebula by direct observation. You will need a decent-sized 'scope. Finding its location is not hard; seeing the bubble IS. Dark skies and an OIII filter are a must. Use averted vision.
The crosshairs mark the position of NGC 7635 (Bubble Nebula):
Here's a larger area view. NGC 7635 is on the right side of the chart, below the border of constellation Cepheus.
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