I agree with Flower, the web image here looks like some species of Fromia to me.
From what I understand, there's actually no such thing as a true orange Linkia genus.....the common Linkia name is used to describe a few stars with roughly the same body type: long, cylindrical arms being the most common feature. The doctor's site lists the orange star as a member of the Echinaster genus, and the "purple linkia" as a member of the Tamaria genus.
Fromias, Linkias, and Echinasters are all difficult animals to keep, despite their beauty. I had a small Fromia for a while before it got caught up in a powerhead (my fault, IMO) but honestly not long enough to consider it a success. These buggers are DELICATE.