|H II region|
|Observation data: J2000 epoch|
|Right ascension||17h 24m |
|Distance||~5900±450 ly (1800±140 pc)|
|Designations||War and Peace Nebula, Lobster Nebula  Sharpless 11, RCW 131, Gum 66|
NGC 6357 is a diffuse nebula near NGC 6334 in the constellation Scorpius. The nebula contains many proto-stars shielded by dark discs of gas, and young stars wrapped in expanding "cocoons" or expanding gases surrounding these small stars. It is also known as the Lobster Nebula and the Madokami Nebula by some fans of the Japanese anime Madoka Magica due to its resemblance to the main character from the anime, and a popular fan petition to rename it.
This nebula was also given the name War and Peace Nebula by the Midcourse Space Experiment scientists because of its appearance, which, in infrared images the bright, western part resembles a dove, while the eastern part looks like a skull.
It is located about ~5,500 light years away from Earth.
This nebula includes the open cluster Pismis 24, which is home to several massive stars. One of the brightest stars in the cluster, Pismis 24-1, was thought possibly to be the most massive on record, approaching 300 solar masses, until it was discovered to be a multiple system of at least three stars; component stars would still remain near 100 solar masses each, making them among the more massive stars on record.
The young stellar cluster G353.1+0.6 lies southeast of Pismis 24 and also contains approximately 800 stars detected by X-ray. The region includes several O-type stars, including [BDSB2003] 10.
NGC 6357 is one of the most prominent sites of massive-star formation in our neighborhood of the Milky Way. A variety of early O-type stars reside in this nebula, blowing the bubbles around the star clusters that can be seen in the molecular cloud.
|Star name||Spectral type||Magnitude
|WR 93 (HD 157504)||WC7||-11.2||71000||10|
|Pismis 24-1NE||O3.5 If*||−10.0||42,000||17||74|
|Pismis 24-1SW||O4 III||−9.8||41,500||16||66|
|Pismis 24-2||O5.5 V(f)||−8.9||40,000||12||43|
|Pismis 24-3||O8 V||−7.7||33,400||9||25|
|Pismis 24-10||O9 V||−7.2||31,500||8||20|
|Pismis 24-12||B1 V||−5.3||30,000||4||11|
|Pismis 24-13||O6.5 III((f))||−8.6||35,600||12||35|
|Pismis 24-15||O8 V||−7.8||33,400||10||25|
|Pismis 24-16||O7.5 V||−9.0||34,000||16||38|
|Pismis 24-17||O3.5 III||−10.1||42,700||17||78|
|Pismis 24-18||B0.5 V||−6.4||30,000||6||15|
|Pismis 24-19||B0.5 V||−5.4||30,000||4||11|
|Wikimedia Commons has media related to NGC 6357.|