Jan 31

What’s Up in the Sky

What’s Up in the Sky – February, 2021

What’s Up With Betelgeuse?

Last month we focused on one of the most prominent and popular constellations, Orion. Now, as if bright nebulae, stars of all sizes and colors, and a sword and belt recognizable by all weren’t enough, Orion’s brightest and most famous (they named a movie after it) star, Betelgeuse, is once again in the news.

Most readers are familiar with Betelgeuse and its position as Orion’s right shoulder as well as its reddish color (hence the designation, “red giant”). Some might even be aware that the star’s brightness varies periodically over a span of 420 days and this is what made some headlines in January and February of 2020. During that time the drop in brightness was 50% greater than the previous year, making the star appear noticeably dimmer. And astronomers both amateur and professional did take notice. In fact, amateurs are the main source of variable star data and they were astonished as well as being jolted into action.

Since the first observations, scientists have been collecting a plethora of data of all types in order to understand the causes of the star’s dimming. The two main theories are: a rapid increase in new dust in the star’s outer shell, or a rare drop in the temperature of its surface. There were some questions about the possibility of the star going supernova and astronomers aren’t certain about that. Chances are pretty good that it won’t be in our lifetimes.

One thing that is certain this month is that some of the best stars and constellations for observing will be visible, assuming clear skies, and Orion is right in the middle of it all. Find Orion’s belt and follow it down and to the left where you will spot Sirius, the most brilliant star in our sky. Known as the Dog Star, it lies in the constellation Canis Major, the Big Dog. Above and to the left of Sirius is the star Procyon (PRO-see-on) in the constellation Canis Minor, the Little Dog. Procyon and Sirius are known as Orion’s hunting dogs. You’ll notice that Canis Minor consists of only two visible stars. Think of them as the dog’s tail. Procyon, Sirius, and Betelgeuse form the Winter Triangle, which needs no further explanation.

This area is also the home of the Winter Hexagon formed by the stars Sirius, Procyon, Castor and Pollux, Capella, Aldebaran, Rigel and back to Sirius. It also contains nine of the 15 brightest stars visible from our latitude north. Observe the Winter Triangle from a dark location and you will see that the Winter Milky Way flows between Sirius and Procyon and just above Betelgeuse.

So whether you use your naked eye, binoculars or a small telescope, there’s much to enjoy up in the sky.

This month in history:

Feb 1: Shuttle Columbia breaks apart during reentry killing all 7 astronauts – 2003
Feb 7: First untethered spacewalk made by Bruce McCandless – 1984
Feb 14: Voyager 1 looks back to take photo of solar system – 1990
Feb 18: Pluto discovered – 1930
Feb 20: John Glenn is first American to orbit Earth – 1962
Feb 23: Light from supernova 1987a reaches Earth – 1987
Feb 24: Detection of first pulsar (by Jocelyn Bell in 1967) is announced – 1968