Mira the Wonderful is waking up! This is a famous star in the constellation Cetus. It gets brighter and then dimmer – too faint to see – over time. Mira is just now brightening. Join EarthSky’s Deborah Byrd and Bob King – aka AstroBob – at noon CST (18 UTC) on Wednesday, January 14. We’ll explain how Mira “breathes,” expanding and contracting over a 332-day cycle. And we’ll talk about what its dramatic changes reveal about the future of stars like our own sun. Mira is heading toward its peak! Learn to see it in the sky and to appreciate it. Join us, and bring your questions!
Mira the Wonderful
The stars seem to shine steadily. But, looking closely, astronomers have found many variable stars, brightening and dimming over different timescales. Their changes in brightness are often too small to perceive with the unaided eye. But the star Mira – aka Omicron Ceti – is different. Its brightness changes are large and distinctly noticeable to the eye.
That’s how this star received its name. The name Mira is derived from the Latin word mirus. It means “wonderful,” “astonishing,” “admirable,” or “miraculous.” And Mira must have seemed miraculous to stargazers around the turn of the 17th century, who first noticed it. Those early sky scientists were just emerging from a time when the heavens were thought of as unchanging.
Depending on when you look for Mira, this reddish star in the constellation Cetus the Whale might or might not be visible. It goes through its bright-to-faint-to-bright cycle about every 332 days. And Mira isn’t visible from late March to June every year. Then, it’s too close to the sun to see. If you’d like to see this unusual star in 2026, now’s your chance. The star is just now becoming bright enough to see with the eye.
Check current observations of Mira here.
What Mira is doing now
Mira brightened enough in December 2025 to be visible to the eye in a dark sky. It should reach its maximum brightness in February or March 2026, when it’ll be setting in late evening (your local time). Note, it’ll set four minutes earlier each day. Generally, you can see it with the unaided eye for about six weeks before it reaches maximum brightness and over two months afterwards. Of course that depends on when Mira reaches its maximum brightness in relationship to when it goes behind the sun.
It’s possible that, in 2026, Mira might still be visible to the eye in a dark sky around the time it’s becoming lost in the sun’s glare.
Then in 2027, its maximum will likely be in January sometime.
How to find Mira
Mira isn’t one of the sky’s brightest stars. Its fame stems from its change in brightness. So catch Mira now, while it’s heading toward its brightest! Then keep watching it as it fades away. Its peak brightness for 2026 comes in February or March.
During these months, as seen from all of Earth, Mira is in the evening sky. For all of us, it’s up as darkness falls. As seen from the Northern Hemisphere, Mira is in the southwest. As seen from the Southern Hemisphere, Mira is closer to overhead. Check Stellarium for a precise view from your location.
Mira is in the constellation Cetus the Whale, which isn’t a prominent constellation. Cetus is faint. You’ll want a dark sky to see it. If you have a dark sky, you can pick out the Whale’s lopsided pentagon of a Head. It might make you laugh! Cetus is depicted as a fierce sea monster in myths about the sky. But it’s really very funny and friendly-looking.
Use the two charts below to starhop to Mira! Start with easy-to-see Orion’s Belt …
Here’s another way to find Mira
Also, look at the chart below. Notice that the distinctive nearby V-shaped Hyades star cluster in Taurus the Bull points to Cetus and its star Mira.
How Mira got its name
Did the earliest stargazers notice Mira as it appeared disappeared and reappeared? If they did, they left no records of this star.
The star’s earliest known history begins just over 400 years ago, when Dutch astronomer David Fabricius first noticed Mira. That was in the year 1596. He assumed Mira was a nova because, as novae do, the star faded away after a few months. But then Fabricus relocated the star 13 years later. It must have surprised him!
Another Dutch astronomer, Johannes Holwarda, was the first to identify Mira as a variable star. He determined a cycle for Mira of about 11 months.
That value was refined in 1667 by French astronomer Ismael Bouillaud to 333 days, very close to the currently accepted value of 332 days.
Mira’s brightness changes led the 17th century astronomer Johannes Hevelius to name the star Mira, from a Latin word that means wonderful. He formally introduced the name in his publication titled Historiola Mirae Stellae (A History of the Wonderful Star), which detailed his observations of the star’s unusual ability to fade and reappear. Read more about Mira’s history from the British Astronomical Association.
Mira is now on track to hit another brightness peak in February or March 2026. How bright will it get? That’s a question many variable star observers are eagerly waiting to find out.
Check current observations of Mira here.
Now you see it, now you don’t
Mira has an average peak brightness of magnitude 3.5. It’s not one of the sky’s brightest stars, even when at its peak brightness. It gradually fades to around magnitude 9 (too faint to see with the eye; for reference, in a dark sky, the unaided eye can barely detect a magnitude 6 star). Then it rebounds back to its peak. So Mira undergoes about a 159-fold change in brightness, as it moves through its 332-day brightness cycle.
It’s impossible to predict exactly how bright or faint Mira will become at each maximum. Have a look at the graph below, called a light curve. Mira-watchers contribute their observations to the American Association of Variable Star Observers (AAVSO). The AAVSO creates an ongoing light curve for Mira, using its Light Curve Generator tool. The light curve below covers the last 10 years. The parts of the plot with no data were when Mira was close to the sun. In 2019 and 2022, Mira was as bright as magnitude 2. That’s almost as bright as Polaris, the North Star, not the sky’s brightest star, but a respectably bright star.
Mira science
So 17th century astronomers marveled at Mira’s brightness changes and considered them a mystery. But modern astronomers know Mira as a red giant star. It’s slightly more massive than our sun but more evolved: Mira is at least 330 times larger in diameter than our sun. Its huge, swollen surface area makes it more than 8,000 times more luminous than our sun.
What else do we know about Mira? It’s some 300 light-years away. It’s thought to be around 6 billion years old. Mira has a faint white dwarf companion star.
There are many types of pulsating variable stars known today. But Mira was the first of its type discovered. And so, astronomers named an entire class of variable stars after it. Mira variables are stars that have one to a few times the mass of our sun. They’re near the end of their stellar lifetimes, at the red giant stage. Mira variables have pulsation periods from 80 to 1,000 days, brightness variations from 2.5 to 10 visual magnitudes. Such stars tend to shed material from their outer layers.
So Mira’s brightness changes aren’t due, for example, to some external factor (such as a disk around the star). They’re caused by the actual expansion and contraction of the entire star, every 332 days. This expansion-contraction oscillation is a complex phenomenon related to changes in the rate that radiation escapes from the star.
Mira’s story is of special interest since our sun will someday follow the same stellar evolutionary path (more or less). About 5 billion years from now, our sun will become a Mira variable.
Why Mira’s brightness changes
For much of its existence, Mira converted hydrogen to helium at its core as a main sequence star. When that fuel was exhausted, its core contracted, causing it to heat up. That heating triggered a new round of hydrogen-to-helium nuclear fusion in a shell around the core, causing Mira to balloon in size into a red giant star. Meanwhile, the collapsing core continued to heat up until it became hot enough for the fusion of helium to carbon, and some oxygen.
Mira is currently at a stage in its stellar evolution called the asymptotic giant branch. Its core of carbon and oxygen is inert. However, the star is still actively “burning” a layer of helium around the core, converting it to carbon. And just outside it, a shell of hydrogen is being converted to helium.
The outer layers of Mira are weakly held by gravity and are starting to waft away. Mira will eventually shed its material to form a planetary nebula, with its exposed hot core – a white dwarf star – left behind.
Mira’s 13-light-year-long tail
In 2006, NASA’s Galaxy Evolution Explorer space observatory (aka GALEX) obtained ultraviolet images of Mira that surprised scientists. They revealed a long comet-like tail of material trailing the star as it speeds through space.
Mira’s tail is about 13 light-years long. It’s composed of gases and dust released by Mira over the last 30,000 years. The amount of gases and dust in Mira’s tail equal about 3,000 times the Earth’s mass.
Why does this star have a tail? It’s because – as a red giant star – Mira’s outer layers are only loosely bound by gravity. And Mira’s pulsations physically lift material away from the star. Plus Mira is plowing through the interstellar medium at about 130 kilometers per second. It’s moving at a speed and in a direction different from the gas and stars around it. That motion creates a bow shock, much like the wave in front of a ship.
And here’s an interesting contrast. Even though our sun is moving much faster than Mira through the galaxy (about 230 km/sec), it doesn’t have a tail like Mira’s. There are two reasons for this. First, sun isn’t a red giant star … yet. The gases in the sun are more tightly bound by gravity.
And, second, our sun is traveling at roughly the same speed and in the same direction as the stars and gas surrounding it. That’s unlike Mira, which is plowing along at a contrasting speed and direction from much of its local environment. That’s why Mira is creating such a strong bow shock ahead of it. As the star moves forward, the shock interacts with the gas in Mira’s tail, causing it to glow — but only in ultraviolet light.
So we needed the orbiting GALEX observatory – which can see in the ultraviolet – to discover Mira’s tail.
Look for Mira again in early 2027
The next upcoming predicted maximum brightnesses for Mira is January or February 2027. Look for Mira around then! That’s when, according to predictions, it should be at its brightest.
The position of Mira is RA: 02h 19m 21s, Dec: -02° 58′ 39″.
Latest observations of Mira from AAVSO
Bottom line: Mira is a variable star that undergoes periodic changes in brightness every 332 days, ranging from a maximum brightness of around 3.5 visual magnitudes to a minimum brightness of about 9 magnitudes. It’s expected to be brightest in February or March 2026.
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