Go outside at 7 p.m. this evening and observe the eastern sky. There will you find a large diamond. Each point in that diamond is marked by a bright celestial object. The brightest of these points, Jupiter, is at the northern tip. The second brightest point, Sirius, is at the bottom. The eastern point star in this diamond, Procyon, is only slightly brighter than the western point, Betelgeuse.
We perceive these points as though they were aligned along the same plane. Our eyes are unable to gauge depth in the night sky.
Nor can we truly discern much difference in the lights of these diamond points. Yes, they are of varying brightnesses and a couple of them reveal a shading not present in the others.
However, our naked eye observation does not reveal how truly different and far apart these celestial objects are.
What is the true nature of these four seemingly similiar light points?
We begin our closer examination right at the top…the brightest of them all: Jupiter
Jupiter is the largest planet in the Solar System. It is the first of the “gas giants,” worlds composed of a solid core enshrouded in a vast sphere of gas.
Jupiter’s “atmosphere” is a kaleidoscopic array of belts, storms, and gases: hydrogen, helium, methane, ammonia. The atmosphere’s most prominent feature, the Great Red Spot, is a storm twice the size of Earth.
We see Jupiter because it reflects approximately 51percent of all incidental sunlight back into space. So, when we observe Jupiter, we’re actually observing solar photons which bounced off the high Jovian clouds.
Jupiter is about five times as far away from the Sun as Earth. A beam of sunlight requires about 43 minutes to reach this giant world.
The second brightest diamond point, Sirius, is, quite understandably, the second closest of the four objects.
Sirius is a white A-type star which is approximately 8.2 light years away. It is the brightest star in the sky, but is certainly not the closest star to the Solar System. (Eight other stars are closer to the Sun than Sirius.) Its name means “The Sparkling One,” for it certainly is an amazingly bright star. It is brighter than the eight “closer stars” because it is hot: its photosphere is more than 13,000 degrees.
Sirius has been the brightest night sky star throughout human history. Yet, within the next 160,000 years, Canopus (not visible from mid-northern latitudes) will assume that honour.
Unseen from Earth except through powerful telescopes is Sirius B: a white dwarf companion to the bright star Sirius A. Sirius B is an amazingly dense sphere of superthick carbon: In fact, it is one of the densest bodies within many cubic light years of the Solar System.
Sirius B is not like most stars: it is a white dwarf. No longer is its core producing the copious amounts of energy being generated in stellar cores like the Sun’s.
Sirius B was the first white dwarf found. Its discovery pre-dated its explanation, for it was initially observed in the 19th century, a few decades before the development of the quantum physics.
Procyon, the eastern point star, is the third brightest star in the diamond. It will not surprise you to know that it is closer than Betelgeuse, but more distant that Sirius.
Procyon is about 11.5 light years away Its name means, “before the Dog,” because the star rises a few minutes before Sirius. Interestingly, Procyon shares some similarities with the Sirius system.
Procyon is slightly cooler (10,000 degrees) than Sirius. But it also has a white dwarf companion. You guessed it: this companion’s name is Procyon B.
Procyon is the brighter star in the two star constellation, Canis Minor: the Little Dog. Canis Minor and Canis Major are the two hunting dogs to the east of Orion.
We find the fourth diamond star in Orion the Hunter. Betelgeuse, the red supergiant, marks the eastern shoulder. It is 520 light years away.
Despite its incredible distance, Betelgeuse still reveals its crimson hue. The red colour indicates a relatively low temperature (by stellar standards) 2200 degrees. It is a variable star: pulsations increase and decrease its volume significantly over time.
Betelgeuse has been described as a red hot “vaccuum.” Even at minimum, it is large enough to accommodate 160 million Suns. Yet, it is only 20 times as massive as the Sun.