ο Cetus, Chinese name: chúgǎo , commonly known as Mira / Mira , is a long-period variable star located in the constellation cetus , about 418 light-years from Earth. Its mass is 1.18 solar masses and its diameter is 700 times that of the Sun. It is a low-temperature, pulsating red giant star that is a model for its kind of variable star.
For ease of reading, the back is collectively referred to as Mira.
To briefly explain, variable stars, refers to stars with fluctuating brightness, assuming that according to observations at different times, sometimes they are first-class stars, sometimes they are second-class stars, generally have a fixed period, and this kind of star that will periodically change brightness is what we call variable stars.
Cetus
(Magnitude is the level used to indicate the brightness of a star, such as: the star with the brightest brightness of the first magnitude, the larger its number, the lower the brightness.) In another case, the brightness of the star we observe with the naked eye is called the apparent magnitude, which is called the absolute magnitude according to the brightness of the star at a distance of 10 seconds ( 32.6 light years ) from the observer. ）
Mira Star Chart
Mira was one of the first non-supernova variable stars ever discovered by humans. The average luminosity is 3.5 magnitude stars, and in each cycle change, the luminosity can reach a 2.0 magnitude star as the luminosity increases. When lowered, it can drop to a 4.9 magnitude star, the luminosity change range reaches 15 times, although most of the energy emitted by Mira is infrared, but the luminosity change in this band is only two magnitudes, and the change in the luminosity curve is about 100 days, and then it decreases in twice as long, so the cycle is about 332 days, that is, 11 months.
In 1600, Mira was confirmed to be a periodic variable star, and Hevellius, who had an infinite passion for the starry sky, named the first star discovered by Fabritius "Stella Mira", transliterated as "Mira", through continuous observations and observations of Mira by many observers over the years. The name Mira Star was derived from this. Mira, who is right at the heart of Cetus, periodically changes her glow like a whale's heartbeat.
Mira is a pulsating variable star that periodically contracts and expands, increasing in brightness as the internal temperature rises when contracting, decreases in temperature and decreases brightness when expanding, resulting in a large change in its own brightness across 2 to 10 magnitudes in a period of about one year. Like a flower accumulating for a long time, and then slowly blooming its beauty. But its cycle is long, even if it will slowly dim, it is not a flash in the pan.
Mira is actually a binary star, Mira A is a red giant, Mira B is a white dwarf, and what we usually see is Mira A.
About Mira, to digress, I don't know if you have seen a "Love Asteroid" Fangwen Society, although there is not much knowledge involved in astronomy, but that is the cause of my interest in astronomy (but also awakened the lily attribute), of which the heroine's name is Mira, the heroine is influenced by the female second, ZhenZhongcang began to like astronomy, and even determined to find an asteroid to use the name "CangXing". Of course, discovering an asteroid is not a simple matter, but with this as a goal, hand in hand, how romantic!