The Cetus constellation, also known as the whale, or the sea monster constellation, is a large collection of interesting stars in an otherwise very clear part of the night sky.
In this article, we’ll look at some of the most interesting facts about the Cetus constellation.
Cetus Constellation Facts, Myth, Location and Stars
1. Cetus is named after a sea monster.
Although the Cetus constellation is usually called “the whale”, the original root of the word Cetus dates back to an ancient Greek classical myth about a sea monster called Cetus, that both Perseus and Heracles needed to kill.
The most common story of the Cetus monster started when Queen Cassiopeia claimed that she and her daughter Andromeda were Nereids or sea nymphs.
This made the god of the sea, Poseidon, really angry. He sent a gigantic sea monster, the Cetus, to destroy the kingdom.
Today, the Cetus is commonly pictured as a kind of whale, but at the time, the Cetus was described as a sea monster or sea serpent, and alternately as having the head of a boar and the body of a river dolphin.
When King Cepheus and Queen Cassiopeia went to an oracle asking him what to do about this problem, he told them that the only solution was to sacrifice their daughter, Andromeda, to Poseidon by offering her to the Cetus monster.
The king and queen had no other choice, so they chained their daughter to the rocks by the ocean when the tide was low so that the Cetus monster would eat her.
When the hero Perseus came along, he saw Andromeda’s problem and helped her by slaying the Cetus monster when it came to kill her.
2. Cetus adjoins all of the water signs.
Like the whale, Cetus is big enough to join together 3 other watery constellations – Pisces (the fish), Aquarius (the water bearer), and Eridanus (the river).
The Cetus constellation also borders some non-water constellations, like Aries, Fornax, Sculptor, and Taurus.
3. How to find the Cetus constellation in the night sky
It’s not that hard to find Cetus, since it lies in a region of the sky without many other stars. The stars in Cetus pop out and are easily visible.
Cetus is most easily seen rising just above the horizon in the early evening in fall and winter.
You can find it to the west of Taurus, or the east of Aquarius.
You will be able to view it if you are anywhere from 70 to -90 degrees.
Cetus is one of the larger constellations in the sky – the 4th largest – and it occupies 1231 square degrees of space or about 3% of the night sky.
4. The Cetus constellation is home to the first variable star ever discovered.
Mira (Latin for wonderful), also called Omicron Ceti, is a binary stellar system with a red giant and white dwarf.
Mira A, the red giant, is a pulsating variable star, the first ever discovered.
Technically, the person who gets the credit for noticing Mira first is David Fabricius, an astronomer who started writing about it in 1596.
He was charting Jupiter and needed reference points, and he realized that a star was becoming gradually brighter before blinking out of existence entirely.
He assumed at first it underwent a supernova – but then it reappeared.
Mira undergoes a process over 330 days in which it grows from an apparent magnitude of 2.0 to 5.0 or even lower.
These changes in luminosity were enough to make David Fabricius wonder if Mira had blipped out of existence.
Mira was the first of these stars ever discovered.
Called Mira variables, there are now more than 7,000 identified.
They are all red giants that are in the last stages of their lives before they transform into white dwarfs.
5. The Cetus constellation contains some interesting stars:
Diphda – also called Deneb Kaitos, or “the whale’s tail” – is formally called Beta Ceti.
This star is the brightest in the Ceti constellation, with an apparent magnitude of 2.04.
It is only about 96 light-years away. Diphda is an orange giant, getting ready to become a red giant.
Menkar – also called Alpha Ceti, has an apparent magnitude of 2.54 and is approximately 249 light-years away.
Menkar is derived from the word “nostrils” in Arabic.
This red giant is unstable and finishing its life before it sheds its nebulae and becomes a white dwarf.
Mira – the first Mira variable star discovered. Mira is a binary stellar system with Mira A being the variable component, and Mira B is a white dwarf companion.
6. Tau Ceti is only 12 light-years away!
It’s still a very long distance, and we don’t have the technology to go and visit yet, but Tau Ceti is on the stars that are closest to our own solar system.
It isn’t the closest, but compared to most other stars, it is practically next door.
Another interesting fact about Tau Ceti is that it is a multi-planetary solar system, like our own.
There are at least 5 planets in orbit around Tau Ceti, which is unusual.
Many stars have just a single planet in orbit around them.
The Whale Constellation – Cetus
It is named after a whale – or a sea monster, if you focus on the original Greek myths – and it is a massive constellation that covers a sizable patch of the night sky.
The Cetus constellation occupies an area of the sky called the water and adjoins some other water constellations, like Pisces, Aquarius, and Eridanus.
This whale constellation contains Mira, the first Mira variable star discovered, with an apparent magnitude that fluctuates over an orbital cycle of 330 days.
As an equatorial celestial constellation, the closer you are to the equator the easier it is to see the Cetus constellation – although technically it falls just to the south of the ecliptic, which is different from the celestial equator.
You can see it most easily in the early evening in the fall and winter.
You might also like learning about:
- Ara Constellation Facts
- Vela Constellation Facts
- Leo Constellation Facts
- Ophiuchus Constellation Facts
- Microscopium Constellation Facts
- Do Constellations Change Over Time?
- Equatorial Constellations
- Indigenous Constellations
- Cool Facts About Constellations
- Is It Ever Possible To See Venus