という is almost a single particle of apposition, that roughly means "called", "named" or "which is". The word has no grammatical equivalent in English, so I can't give the "exact" translation of itself independent from sentence.
lit. at/in/on a planet by/with name of love
"on a planet that has the name 'love'"
Yes, it often disappears in natural English translation (as in the planet Earth, the word impossible etc).
という and という名（前）の also has subtle difference. When you say
X という Y you refer to the entity mentioned by the name X, but when
X という名前の Y, you're only sure about the name and it could mean "any" Y named X.
オバマという男は大統領だ。 A man known as Obama is president. → true
オバマという名前の男は大統領だ。 A man whose name is Obama (you can pick) is... → false
そのオバマという名前の男は大統領だ。 The man whose name is Obama is... → true
オバマという名前の男が大統領だ。 The president is a man whose name is Obama. → true
The spelling is 愛という名前の惑星【ほし】で in the original lyrics OP mentioned, which is a creative ateji.