Heliaster helianthus, the sun star, is a species of Asteroidea (starfish) in the family Heliasteridae.

It is found in shallow water rocky habitats and in the kelp forests off the Pacific coast of Ecuador, Peru and Chile.

Heliaster helianthus is a multi-armed starfish, the number of arms usually being in the range 28 to 39, and the diameter typically being between 16 and 20 cm (6 and 8 in).

[3] This species is present in the southeastern Pacific Ocean, along the west coast of South America.

Having trapped its prey, M. gelatinosus everts its stomach over several arms of its victim, which become autotomised in response to the predation.