The Omega Nebula,
also known as the Swan Nebula,
Checkmark Nebula, Lobster Nebula,
and the Horseshoe Nebula (catalogued
as Messier 17 or M17 and as
NGC 6618) is an H II region in the
constellation Sagittarius. It was discovered
by Philippe Loys de Chéseaux in 1745.
Charles Messier catalogued it in 1764. It is
located in the rich star fields of the
Sagittarius area of the Milky Way. The Omega
Nebula is between 5,000 and 6,000
light-years from Earth and it spans some 15
light-years in diameter. The cloud of
interstellar matter of which this nebula is
a part is roughly 40 light-years in
diameter. The total mass of the Omega Nebula
is an estimated 800 solar masses.An open
cluster of 35 stars lies embedded in the
nebulosity and causes the gases of the
nebula to shine due to radiation from these
hot, young stars.
|
|