私の名前 ”NEPTUNE” で、星の名前【海王星】。でも、一体なぜ「海王星」なんていう大層な名前を姓として名乗るようになったのか・・・
I have a very unusual last name: Neptune. Although it's famously a planet and a Roman God, it's unlikely that anyone will have met another person with it as a surname. According to one ancestry website, less than five people are born into it every year, and almost all of them are born in America.
*surname = 姓、苗字
That's because it's not a very recent surname. The first recording of it in birth records in America was in 1840. It may have come from England, but it may also have started as a misspelling of the name Napton. It may also have been transliterated from an unrelated Polish surname, or it may have been written down incorrectly on a ship manifest for eastern Europeans immigrating to America.
*transliterate =書き直す、音訳する、字訳する manifest =乗客名簿
Regardless, it is a very uncommon surname. Information about surnames and family history can be found on ancestry websites such as Ancestry.com. Many Americans like to learn about their family history through sites like this as well as DNA tests from services such as 23andme.com. This practice betrays both a beautiful curiosity that Americans have about their complicated multicultural history, as well as a sometimes embarrassing obsession many have with their ethnic origins.
*betray =裏切る、（秘密などを）漏らす、（実態などを）表す multicultural =多文化の
Personally, I just know mine because it's pretty stupid for a pale white guy to be named after a Roman God.
Have a great week!