What It Is
M17, the Omega Nebula, is a bright emission nebula and active stellar nursery in Sagittarius. Young, massive stars embedded in the region flood the surrounding gas with ultraviolet light, making the hydrogen-rich cloud glow while dust lanes carve the familiar swan and omega shapes.
History
Swiss astronomer Jean-Philippe Loys de Cheseaux discovered the nebula in 1745, and Charles Messier independently cataloged it in 1764 while building his list of comet-like objects. Its changing silhouette has given it several popular names, including the Swan Nebula, Horseshoe Nebula, Lobster Nebula, and Checkmark Nebula.
Science Notes
- NASA lists M17 at about 5,500 light-years away with an apparent magnitude near 6.0, bright enough for binoculars under clear dark skies.
- The nebula is one of the Milky Way's large star-forming regions, with hot young stars sculpting the gas through radiation and stellar winds.
- The embedded young cluster NGC 6618 helps power the nebula's glow, though much of the youngest stellar population is hidden by dust.
- Hubble views show dense pockets of cold gas and dust being eroded by nearby young stars, leaving pillars, knots, and future star-forming sites.
- distance
- 5,500 light-years
- apparentMagnitude
- 6.0
- constellation
- Sagittarius
- objectType
- Emission nebula
- alsoKnownAs
- Swan Nebula, Horseshoe Nebula, Lobster Nebula, NGC 6618
- associatedCluster
- NGC 6618
- coordinates
- RA 18h 20m 47s, Dec -16° 10' 20"
- bestObserved
- August from mid-northern latitudes
