Given a question and a context passage, generate the answer having the word or phrase from the context passage. Here, the answer should be a shortest continous span from the passage.
Q: Context: 35 Leukothea (/ljuki/ lew-KOTH-ee-, Greek: ) is a large, dark asteroid from the asteroid belt It was discovered by German astronomer Karl Theodor Robert Luther on April 19, 1855, and named after Leukothea, a sea goddess in Greek mythology.
Question: Who discovered the 35 Leukothea?
A:
robert luther