Interstellar cloud | |
---|---|
H I region | |
Observation data: J2000 epoch | |
Right ascension | 00h 55m [1] |
Declination | +61° 24′[1] |
Distance | 12,400 ± 3,900 ly (3800±1200[2] pc) |
Constellation | Cassiopeia |
Galactic Worm 123.4-1.5 (GW 123.4-1.5) is an H I region with a mass of approximately 105 MSun.[3] It has an unusual mushroom-shaped structure that may be the result of having been formed by an infalling cloud slamming through the disc of the Milky Way from the other side. The high-velocity cloud in question is theorized as having hit at around 100 km/s, 5×107 years ago.[2]