Object Description

The reflection nebula IC 4603 (LBN 1109) lies roughly in the center of the large area of nebula called Ophiuchus Molecular Cloud, which spans an area of about 4.5° × 6.5°. This also includes IC 4604, IC 4605, the Antares nebula vdB 107, Sharpless 2-9 and many dark clouds. The IC numbers were discovered in 1882 by the American astronomer Edward Barnard, who also recorded the dark clouds B 42, B 44 and B 45. The star cluster in the center is surrounded by dense dust and is only visible on infrared images. ^{[196, 239, 270, 277]}

The Ophiuchus Molecular Cloud, also called Rho Ophiuchus Cloud, is an area with active star formation, which is one of the closest to us at a distance of only about 407 light years. X-ray and infrared observations revealed more than 300 young stars within the large cloud in the center. The age of these stars is estimated to be only 300,000 years - very young compared to the oldest stars in the universe, which are more than twelve billion years old. ^[460]

Finder Chart

The nebula IC 4603 is located in the constellation Ophiuchus (Serpent Bearer) about one degree south of the 5 mag star ρ Ophiuchi, or about two degrees north of the bright star Antares (α Scorpii) in the constellation Scorpius (Scorpio). The best observation time is April to August.