As the calendar turns to February, and the prospect of warm, sunny, and longer daylight hours seem far away, the prominent winter constellation of Orion the Hunter shines brightly in the evening sky this month.
Orion, with the three prominent stars in a line that make up his belt, is an easily seen winter constellation. However, stare at it closely and you may notice something is going on with the reddish star up and to the left of its belt — Betelgeuse (pronounced “betal-jooz”) is not as bright as it used to be. In fact, this winter Betelgeuse has only been half as bright as it was last winter! What’s going on?!
We’ve known now for decades that Betelgeuse is a “red supergiant” star because, well, its red and it’s huge! Replace the Sun in our Solar System with Betelgeuse and the 4 inner planets (Mercury, Venus, Earth, and Mars) would be engulfed by the star! It truly is a giant. Betelgeuse is also a star that is at the end of its lifecycle and is going to explode any moment now. Of course, in astronomy any moment now means tonight or it could mean in thousands of years as the star is about 8 million years old.
So is the dimming of Betelgeuse telling us it's about to explode? We don’t know. Betelgeuse is also a star that is known to have its brightness vary with time, but we’ve never seen it this dim in decades. It has become so dim that Betelgeuse isn’t even the brightest star in Orion anymore — that distinction belongs to Rigel, the bluish-white star down and to the right of Orion’s belt.
Whatever may be going with Betelgeuse, step outside this month, gaze into the night sky, and ponder the mystery of what may be going on with Betelgeuse. Maybe this will be the last winter we’ll get to see it!
Where are the planets this month?
Mars is a little brighter this month but you still have to get up early to see the Red Planet.
If it’s clear, go outside on the morning of Tuesday, Feb. 18, and observe the Moon eclipse Mars. A planet eclipsed by the Moon is called an occultation. Mars and the Moon will be low in the sky, and the impending sunrise will make it difficult to see, so binoculars or a small telescope will definitely help.
Jupiter is now easily seen in the morning sky. Watch how Mars slowly moves closer to Jupiter. By March 20, they will be at their closest in the morning sky.
Saturn also becomes visible in the morning sky. It will be hard to see at the start of February, but the ringed planet rises two hours before the Sun on Leap Day morning.
Venus climbs even higher this February in the southwest after sunset. The Moon wanders by, making great celestial pairings near the end of the month.
Mercury is visible in early February—far below Venus—in the West-Southwest evening sky. Look just above the horizon about 30 to 40 minutes after sunset.