Proplyd

[2] In 1979 observations with the Lallemand electronic camera at the Pic-du-Midi Observatory showed six unresolved high-ionization sources near the Trapezium Cluster.

Here the idea appeared that these objects might be low-mass stars surrounded by an evaporating protostellar accretion disk.

Other proplyds are found at a greater distance from the host star and instead show up as dark silhouettes due to the self-obscuration of cooler dust and gases from the disk itself.

[20] In addition, 4 clear and 4 candidate proplyds were discovered in the very young region NGC 2024, two of which have been photoevaporated by a B star.

[21] The NGC 2024 proplyds are significant because they imply that external photoevaporation of protoplanetary disks could compete even with very early planet formation (within the first half a million years).

[24] The proplyds in the Orion Nebula and other star-forming regions represent proto-planetary disks around low-mass stars being externally photoevaporated.

Objects in NGC 3603 and later in Cygnus OB2 were proposed as intermediate massive versions of the bright proplyds found in the Orion Nebula.