IC 4605 is a reflection nebula visible in the constellation Scorpio .

It is located in the northern part of the constellation, just over 1 ° north of the red star Antares ; it is a part of the gas of the Cloud of Rho Ophiuchi that appears illuminated by the radiation of the star Scorpii , also known as HD 148605, a young blue star of main sequence of spectral class B3V. The intensity of the radiation received from the gases is insufficient to ionize its molecules, so the cloud is limited to reflect the light of the star, also appearing blue in color. The physical link between the star and the Cloud by Rho Ophiuchi is also proven by the measurement of its parallax , which places the Scorpii at a distance of about 121 parsecs (393 light years ), comparable to that of the cloud itself.

Few first northeast of the star extends one of the two major strands of the Cloud of Rho Ophiuchi, cataloged as LDN 1689; this cloud houses some very studied young star objects , among which the IRAS infrared source 16293-2422, coinciding with a multiple star in formation, stands out.