70-year star in Talmud confusing sailors?
Comets can look like stars. Sometimes the outside of the coma and tail of the comet are too faint to see with the naked eye, and only the central part of the coma is bright enough to be seen. In this case the comet will appear like a (slightly fuzzy) star.  Look at the Great Nebula in Orion. It appears star-like, perhaps a little fuzzy.  Other clusters and nebulae were initially classified as "stars".

Moreover in the language of the first century AD (and until relatively recently) the word "star" meant "any heavenly light" and included comets, planets, and meteors. A navigator at that time would consider a comet to be just a "hairy star", while the learnéd debated whether comets were astronomical or meteorological stars.

At the time, many people also believed in "astrology" (the belief that the stars could have magical influences on life on Earth). It would seem quite reasonable, then, to think a star that appears every 70 years could affect navigation in mysterious ways.

As with many such ancient texts, the correct interpretation is probably lost. I'd consider it to be a parable: A man may be knowledgable and wise (as evidenced by his knowledge of the stars) but still be poor. I see no reason to try to identify the "star", no more that I would try to identify the farm in Isaiah 28. Trying to prove the story is "scientifically correct" seems to miss the point.