The Moon is especially close to a star with a dangerous-sounding name tonight: El Nath, “the butting one.” It marks the tip of one of the horns of Taurus. It’s the bull’s second-brightest star.
El Nath is most famous for its location. It’s the closest bright star to the galactic “anticenter” — the point directly opposite the heart of the Milky Way Galaxy. So when we look in that direction, we’re looking toward the galaxy’s rim. El Nath isn’t on the rim, though. It’s about 135 light-years away, while the rim is more than 20,000 light-years farther.
El Nath is interesting for more than just its direction, though. It’s a stellar giant. It’s about five times the mass of the Sun, so even though it’s only a couple of percent the Sun’s age, it’s already past the prime of life. It’s puffed up to several times the Sun’s diameter, and it’s much hotter than the Sun. The combination makes it about 700 times brighter than the Sun.
Over the next few million years, El Nath will get even bigger and brighter. Then it will cast its outer layers into space, leaving only its hot but dense core — and the bull will lose his impressive horn.
El Nath is close to the left or lower left of the bright gibbous Moon at nightfall. Two brighter lights are in the opposite direction. Mars and Aldebaran stand to the upper right of the Moon. Mars is the brighter of the two orange lights, and stands a little higher in the sky.
Script by Damond Benningfield