Yes, the 13th or “forgotten constellation” of the zodiac is Ophiuchus. The sun passes in front of Ophiuchus from about November 30 to December 18. And yet no one ever says they’re born when the sun is in Ophiuchus. That’s because Ophiuchus is a constellation – not a sign – of the zodiac.
We’ve had a conversation about it a while back: New Horoscope- thoughts