Ophiuchus

No. The Sun does pass through Ophiuchus for roughly 18 days each year (about November 30 to December 18), but the International Astronomical Union, which recognizes 88 constellations, has never defined the astrological zodiac. The '13th sign' idea periodically goes viral, often traced back to a NASA educational post about how the Babylonians chose 12 signs.

Ophiuchus straddles the celestial equator between Scorpius and Sagittarius, next to Hercules, with its brightest star Rasalhague marking the serpent bearer's head. From the Northern Hemisphere it is best viewed on summer evenings around July. It is one of the largest constellations in the sky.

It contains Barnard's Star, one of the Sun's nearest neighbors at roughly six light-years away, and the dark Snake Nebula (Barnard 72). Kepler's Supernova of 1604, the last supernova observed in our own galaxy, also appeared in Ophiuchus.

It depicts a figure holding a serpent, represented by the neighboring constellation Serpens, and is associated with Asclepius, the Greek god of medicine. It was one of the 48 constellations recorded by the astronomer Ptolemy in the Almagest in the 2nd century, and it remains among the 88 constellations recognized today.