The constellation Cassiopeia is one of those that are always present in the Ukrainian sky. In ancient times, our people called it “Harrow”, and now they often see the letter “W” or “M” in it. However, it is interesting not only in the shape formed by its five brightest stars.
1. How to find the constellation Cassiopeia?
The constellation Cassiopeia is hard to miss in the sky of Ukraine. It is one of those that are located near the North Pole of the world and does not fall below the horizon in our latitudes. And five bright stars forming either the letter “M” or “W” are hard to miss.
But if you still can’t do it, here’s a reliable way for you. Start by finding two “dippers” in the sky — Ursa Major and Ursa Minor. Next, you need to find the second star from the end of the “handle” of the first of them (Mizar) and connect it with the Polar Star on the “tail” of the small one. Continuing this line further, you will find Cassiopeia.
2. Why is the constellation called like that?
The constellation Cassiopeia was known to ancient authors. And its name comes from Ancient Greece. It is the name of the mythical Queen, who is the wife of Cepheus, Andromeda is the mother, and Perseus is the mother-in-law. All four constellations are located side by side in the sky.
Cassiopeia as a character is mainly known for bragging to the nymphs that she or her daughter is more beautiful than them. For this, Poseidon sent a sea monster to their country, and the queen had to give the girl to him as a sacrifice. However, Perseus managed to save her after many adventures.
3. Which star in the constellation Cassiopeia is the brightest?
At first glance, all five stars that form an asterism in the form of the letter “M” are approximately equally bright. However, accurate research has shown that the brightest of them is the one that forms the left top of this letter — α Cassiopeia, or Schedar.
The name of this star means “breast” in Arabic. This is an orange giant, 230 light-years away from us. In diameter, this luminary exceeds the Sun by 42 times, and in luminosity — by 855 times.
4. Which star in the constellation Cassiopeia is the nearest?
The nearest star of the constellation Cassiopeia to Earth is indicated by the Greek letter η (eta). The distance to it is only 19 light-years, which is very close on a cosmic scale. At the same time, it is not among the five brightest, although it is visible to the naked eye.
To find η Cassiopeia, you need to move from the already mentioned Schedar to the middle of the letter “M” — γ Cassiopeia. In the middle of the way, you will meet a weak star. This is what you are looking for.
η Cassiopeia has its own name Akhird, which means “knee”. In fact, it is a system of two luminaries orbiting a common center of mass with a period of 480 Earth years. The larger one is almost exactly like the Sun in size and brightness, the smaller one is an orange dwarf with a mass of about 60% of the solar one.
5. What is Cassiopeia A?
There is another interesting object in the constellation Cassiopeia — the radio source Cassiopeia A. It should not be confused with α Cassiopeia, that is, the star Schedar. It is an extremely powerful radio signal source, discovered in 1948. It is a remnant of a supernova explosion — a pulsar or magnetar surrounded by a nebula that is very difficult to observe in the visible range.
Interestingly, the explosion of the star should have been seen on Earth about 300 years ago. It is believed that this was the “latest” supernova that broke out in our Galaxy. However, the astronomers of the XVII century did not notice this extraordinary event for some reason.
There is a version that this star was extremely massive and, at the end of its existence, threw a large amount of gas into space. The newborn nebula hid most of the radiation in the optical spectrum and made the outburst almost invisible.
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