If you ask most people what a birth star
is, almost certainly he/she will relate it somehow to astrology. The thought makes
me cringe. Although there really is no such thing as a birth star, there is such
a thing as a star whose distance from Earth is equivalent in light-years to the
day you were born. That means the light leaving the star actually began radiating
in the direction of Earth within a few months of the day you were born. For instance,
I was born on August 18, 1958, which was 54.5 years ago. All that's needed to find
my birthday star is to find one that is 54.5 light-years away. Fortunately, there's
an app for that.
Per the Joint Astronomy Center website's
birthday star finder: (the original website is gone)
"Your birthday star is in the constellation Taurus. It is called 39 Tauri in
the Historia Cœlestis Britannica of John Flamsteed and Edmund Halley. It is called
NS 0405+2200 in the NStars database. It has visual magnitude 5.9 meaning that you
could just see this star with the naked eye under the best viewing conditions. It
is marked in the center of this star chart, at celestial coordinates (J2000 equinox):
Right ascension = 4:5:20.3, Declination = 22:0:32.1 This star is 54.5 light years
away, which means that the light we see from it today set off on its journey at
about the same time that you were born. Come back in a month or two and your birthday
star may change, as the light from more distant stars reaches Earth."
That's real nice to know; however, your (and my) birthday star changes all the
time. If I was to re-run the birthday star finder a year from now, my star would
be different because the current equivalent distance would be a light-year farther
away. In fact, the new star would be
(Tau01) Hydrae in the constellation Hydra.
Here is a currently functional
Star Finder (it gives a different star for my birthday).
Posted June 25, 2021(original