NGC 604とは 意味・読み方・使い方

NGC 604 is a H II region inside the Triangulum Galaxy. It was discovered by William Herschel on September 11, 1784. It is one of the largest H II regions in the Local Group of galaxies; at the galaxy's estimated distance of 2.7 million light-years its longest diameter is roughly 1500 light-years (460 parsecs), over 40 times the size of the visible portion of the Orion Nebula. It is over 6300 times more luminous than the Orion Nebula, and if it were at the same distance it would outshine Venus. Like all emission nebulae, its gas is ionized by a cluster of massive stars at its center.