Red-Orange Stars and a Planet: Betelgeuse, Aldebaran and Mars

Mars is making a splash in the evening sky this winter, and it's near two stars that appear quite similar in color and brightness. Mars is presently in the constellation Aries, which is next to the next Zodiac constellation Taurus and the bright orange-giant star Aldebaran. The two objects are quite similar and at a glance, one can see the colors shining through. But if you move just a little further east along the line that connects Mars to Aldeberan, you will find the bright red-supergiant star Betelgeuse, which marks the upper left shoulder of the giant constellation Orion. Betelgeuse is one of the largest objects in the Milky Galaxy, a truly giant star that would encompass the orbits of the planets nearly out to Saturn if it was in the same place as our Sun. 

Mars is slowly working its way eastward across the sky, such that in a few weeks it will be very close to the Pleiades and continue its march across Taurus and then through Cancer. Mars has had a busy year, with its closest approach to Earth last year and now getting ready to host three new spacecraft that will land there in the coming days, the UAE Hope spacecraft, the Chinese Tianwen-1 spacecraft, and the NASA Perseverance lander with a new rover ready for further exploration and discovery on Mars. 

Image courtesy Sky & Telescope. 

Winter Triangle

One of the highlights of the winter sky is the Winter Triangle. This shape is a nearly perfect equilateral triangle that shines in the southern sky over the next few months. It includes three of the most brilliant stars in the sky, and it is called an "asterism" because it is not a single constellation, but a combination of stars from three different constellations.

The first and brightest star is Sirius, the brightest star in the night sky. Sirius is close to the Solar Systems (8 light years) and has a slight blue coloration. Sirius is in the constellation Canis Major, the big dog that accompanies Orion. To the upper right is Betelgeuse, a red supergiant star in Orion that is a distinctive orange color. Betelgeuse is so big that if it was our Sun, it would envelop Mercury, Venus, Earth and Mars! And the third star of the triangle is Procyon, in the constellation Canis Minor, the small dog that accompanies Orion. Procyon is actually a double-star system with a faint partner star.

Inside the Winter Triangle you can find numerous clusters of stars. I spent some time looking here a few nights ago and was able to see quite a few of these clusters, even in San Francisco. My backyard has a dark western horizon so by looking through binoculars later in the evening I was able to see quite a bit in and around the asterism. Try this for yourself sometime soon.