It was discovered by the British astronomer William Lassell on 10 October 1846, just 17 days after Neptune itself was discovered by the German astronomer Johann Gottfried Galle and Heinrich Louis d'Arrest.
ɪ t WORD_BOUNDARY w ʌ z WORD_BOUNDARY d ɪ s k ʌ v ə ɹ d WORD_BOUNDARY b aɪ WORD_BOUNDARY ð ə WORD_BOUNDARY b ɹ ɪ t ɪ ʃ WORD_BOUNDARY ʌ s t ɹ ɑ n ə m ə ɹ WORD_BOUNDARY w ɪ l j ə m WORD_BOUNDARY l æ s ɛ l WORD_BOUNDARY ɔ n WORD_BOUNDARY t ɛ n WORD_BOUNDARY ɑ k t oʊ b ə ɹ WORD_BOUNDARY w ʌ n WORD_BOUNDARY θ aʊ z ə n d WORD_BOUNDARY eɪ t h ʌ n d ɹ ɪ d WORD_BOUNDARY f ɔ ɹ t i WORD_BOUNDARY s ɪ k s WORD_BOUNDARY d̠ʒ ʌ s t WORD_BOUNDARY s ɛ v ə n t iː n WORD_BOUNDARY d eɪ z WORD_BOUNDARY æ f t ə ɹ WORD_BOUNDARY n ɛ p t uː n WORD_BOUNDARY ɪ t s ɛ l f WORD_BOUNDARY w ʌ z WORD_BOUNDARY d ɪ s k ʌ v ə ɹ d WORD_BOUNDARY b aɪ WORD_BOUNDARY ð ə WORD_BOUNDARY d̠ʒ ɜː m ə n WORD_BOUNDARY ʌ s t ɹ ɑ n ə m ə ɹ WORD_BOUNDARY j oʊ h ɑ n WORD_BOUNDARY ɡ ɑ t f ɹ i d WORD_BOUNDARY ɡ ɑ l ə WORD_BOUNDARY æ n d WORD_BOUNDARY h aɪ n ɹ ɪ t̠ʃ WORD_BOUNDARY l uː i WORD_BOUNDARY d ə ɹ ɹ ɛ s t WORD_BOUNDARY