Sh2-101 (Tulip Nebula) and Cygnus X-1

Sh2-101 (Tulip Nebula)

A star forming region in Cygnus about 6000 light years from earth.

Not only young stars just being born populate this region but also an already dead star has been identified. Cygnus X-1 can be found not too far from the main nebula in this image. First discovered as the strongest X-ray source in constellation Cygnus (hence its name), it has become the first stellar black hole discovered in our Milky Way galaxy.

It seems to belong to the young OB association of bright massive stars embedded in the visible nebula. It’s progenitor star must have been very massive (about 40 times the mass of our sun) and has terminated its life pretty early. The remaining black hole is now part of a binary system. It’s partner is another massive star orbiting the black hole at very short distance, so that the black hole strips a substantial amount of matter from its neighbor. The material is dumped into the accretion disk around the black hole, heated, accelerated and partly ejected in powerful jets into the surrounding gas. The bow shock created by these jets and the stellar partner of the black hole are clearly visible in this image: the bow shock right to the Tulip Nebula and a bit below the bow the bluish star from a unequal pair of stars, the other star shining in pretty orange color.

Borg 90FL
1.08 Flattener
ASI 2600MM Pro
Baader Ultra-Narrowband 3.5/4nm and RGB filters
H: 24x300s
OIII: 24x300s
SII: 26x300s
R/G/B: 12x60s each
Total Integration: 6h46m over 4 nights
Bortle 4-5


Sh2-101 cropped