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Stars are among the most vital celestial objects in our universe. We've already explored some of the most mesmerizing—and most perilous—planets that revolve around these stars, but these radiant cosmic bodies are captivating in their own way.
We typically picture stars as enormous, scorching spheres of hydrogen and helium, but they don't always fit this image. Astronomers have uncovered many stars that challenge our traditional understanding. These surprising findings are truly captivating.
10. The Egg-Shaped Star
What could be more fascinating than a round star? Certainly one that’s shaped like an egg.
Introducing Vega (also known as Alpha Lyrae or Alpha Lyr), an egg-shaped star located 25 light-years from Earth. It's one of the most well-known stars, and astronomers seem to focus more on it than our very own Sun.
Vega's peculiar shape is due to its incredibly fast rotational speed, which is 93 percent of its critical velocity (also called “critical rotation,” the maximum speed at which a star would break apart). Vega spins so quickly that it completes a full rotation in only 12.5 hours, while our Sun takes 27 days to do the same.
This rapid rotation has caused Vega to bulge 23 percent more at its equator than at its poles. This strange shape has led to so much energy being transferred from the equator that it’s 2,200 degrees Celsius (4,000 °F) cooler than at the poles.
9. Two Enormous Stars Colliding to Form One
More than ten years ago, astronomers found a massive star in the Camelopardalis (“Giraffe”) constellation, located 13,000 light-years from Earth. They named this system MY Camelopardalis.
At first, stargazers thought they were observing a single enormous star. However, astronomers quickly realized they were actually seeing two massive stars in close orbit around one another. These two stars complete their orbits in just 1.2 days.
The larger star has a mass 38 times that of the Sun, while the smaller star weighs 32 times as much as our Sun. Later on, astronomers discovered that these stars will eventually collide and form a colossal stellar entity with a mass 60 times that of the Sun.
The stars' atmospheres are already interacting, and this process will continue until their cores merge into one. While the precise outcome remains unknown, astronomers predict that the collision will cause a massive explosion that releases an enormous amount of energy.
8. The Star With Spiral Arms
When we think of spiral arms, we usually picture galaxies like the Milky Way. But star SAO 206462 challenges that image, as it features two spiral arms. Located in the Lupus (“Wolf”) constellation, approximately 460 light-years away, SAO 206462 is encircled by a vast circumstellar disk made up of dust and gas.
This expansive disk is nearly twice the width of Pluto's orbit. Astronomers understand that spiral arms can emerge around a star when new planets are forming within its disk. In fact, it’s believed that the two spiral arms were created by two new planets growing within the disk.
7. The Star With Water Clouds
We know that stars are incredibly hot. For example, our Sun’s photosphere averages around 5,500 degrees Celsius (10,000 °F). But what about a star with a temperature of just 100 degrees Celsius (212 °F)? That’s the boiling point of water—far too cold for a star. Yet, that’s the temperature of CFBDSIR 1458+10B (shown above on the right).
Located 75 light-years from Earth in the CFBDSIR 1458+10 binary system, CFBDSIR 1458+10B is a brown dwarf. A binary system consists of two stars that orbit one another.
The mass of a brown dwarf lies between that of a massive planet and a small star. It's too large to be classified as a planet, yet too faint to be considered a proper star. Brown dwarfs are often referred to as failed stars since they lack sufficient mass for gravity to initiate nuclear fusion, which is the process that powers stars by producing light and heat.
Even so, CFBDSIR 1458+10B is unusually cold for a brown dwarf. Most brown dwarfs have temperatures between 177–327 degrees Celsius (350–620 °F), which are still much hotter than CFBDSIR 1458+10B’s chilly 100 degrees Celsius (212 °F).
Astronomers believe that the conditions on CFBDSIR 1458+10B resemble those of a large planet rather than a typical brown dwarf. They even speculate that this cold brown dwarf might have clouds containing water.
6. The Star That Became a Diamond Planet
It’s rare to hear of a star transforming into a planet, let alone a planet entirely covered in diamonds. But that’s exactly what happened with this unnamed star.
Astronomers discovered this star-turned-planet when they detected some pulsar signals from our Milky Way. Pulsar signals are radio waves and radiation emitted by rapidly spinning neutron stars, which are the collapsed cores of deceased massive stars.
Astronomers noticed something unusual when they observed that the pulsar's spin seemed to be influenced by gravity. This type of spin could only occur if an exoplanet was orbiting the pulsar.
Indeed, astronomers found an exoplanet swiftly orbiting the pulsar at a very close distance. Despite its size being only five times that of Earth, the exoplanet had an enormous mass similar to Jupiter’s. Initially, this seemed impossible—a planet so massive shouldn’t be so tightly packed while orbiting so close to a high-gravity star.
It was soon revealed that the exoplanet had once been a star in a binary system, with the pulsar as its companion. The two stars had orbited each other until they exhausted their fuel and came so close that the larger one pulled material from the smaller one.
What resulted was a cold planet orbiting a pulsar. Yet, amidst this destruction lies beauty. Astronomers believe this fusion-less planet is made of crystalline carbon—the same substance that forms diamonds.
5. The Star Within A Star
A Thorne-Zytkow object (TZO) is a star embedded within another star. The concept was introduced by physicist Kip Thorne and astronomer Anna Zytkow in 1975. They suggested that TZOs form when a neutron star is engulfed by a red supergiant star.
As previously discussed, a neutron star is the collapsed core of a dead giant star. A red supergiant is an aging star that is nearing the end of its hydrogen reserves, which it needs to generate light and heat. Red supergiants are the largest stars known, with diameters that can extend up to 2,000 times that of the Sun.
In 2014, astronomers thought they had identified a TZO, which they named HV 2112. Located in a dwarf galaxy 199,000 light-years away from Earth, HV 2112 appears to be an exceptionally bright red supergiant. However, it is classified as a TZO due to the presence of unusually large amounts of elements not typically emitted by standard red supergiants.
4. The Roundest Star
We often assume that planets and stars are perfectly round, but in reality, they are wider around their equators due to the centrifugal force generated by their rotation. Located about 5,000 light-years from Earth, Kepler 11145123 is a star that holds the title of being the roundest natural object currently known.
Generally, the faster a planet or star rotates, the more pronounced its equatorial bulge becomes. Earth itself isn’t a perfect sphere, nor is the Sun or Kepler 11145123. Nevertheless, Kepler 11145123 is remarkably close to spherical.
Earth’s equator is 21 kilometers (13 miles) wider than its poles. By comparison, the Sun’s equator is about 10 kilometers (6 miles) wider, and Kepler 11145123 has an equatorial bulge of only 6 kilometers (4 miles). This is especially impressive considering that Kepler 11145123 is twice the size of the Sun.
Astronomers acknowledge that their estimate for the diameter of Kepler 11145123 may vary by a few kilometers, but the margin of error is minimal. On average, the star’s diameter measures 3.2 million kilometers (2 million miles).
3. The Star With A Tail
When we think of tails in space, our minds often drift to comets. However, Mira (“Wonderful”) challenges this assumption. Located 350 light-years away in the Cetus constellation, Mira is a binary star system. One component is Mira A, a red giant, and the other is Mira B, a white dwarf. A red giant represents a dying star, while a white dwarf is the remnant of a star that has already exhausted its fuel.
Astronomers made the discovery while observing the universe through ultraviolet light. They initially thought the tail they detected belonged to a comet, stretching a remarkable 13 light-years long—about 20,000 times the distance from Pluto to the Sun. However, they quickly realized that the tail originated from the red giant, Mira A.
The tail is shedding various elements, including carbon and oxygen, which astronomers speculate could play a role in the formation of new solar systems. Mira has been ejecting these materials for more than 30,000 years.
2. The Double Double Star
The Epsilon Lyrae star system, located 160 light-years from Earth, holds a fascinating secret. From a distance, it seems like a binary system, with two stars orbiting each other. But on closer inspection, each star is actually part of its own binary system. In other words, each of these stars is actually a pair of stars orbiting each other, and these pairs themselves orbit around the other pair. This creates a unique formation known as ‘The Double Double’—a binary within a binary.
To the naked eye from Earth, each stellar pair appears so close together that one might mistake them for single stars. However, in reality, the stars are far apart, with each member of a pair taking about 1,000 years to complete an orbit around its companion.
The binary pairs themselves are also quite distant from one another. The separation between the two pairs is 10,000 times the distance between the Earth and the Sun. It takes around 500,000 years for these two binaries to complete one revolution around each other.
Interestingly, astronomers have found a fifth star orbiting one of the stellar pairs in the Epsilon Lyrae system. Researchers also suspect that other undiscovered stars may be present, leading them to believe the system may involve a total of 10 stars.
1. A Star Smaller Than Jupiter
While stars are typically thought of as massive celestial objects, some can be quite small—comparable in size to planets like Saturn. To put it into perspective, Saturn is so large that approximately 764 Earths could fit inside it.
However, Saturn’s size still pales in comparison to that of our Sun, which could contain about 1.3 million Earths within its volume. Even more surprising is the fact that Saturn is smaller than Jupiter, the largest planet in our solar system. In fact, astronomers have identified a star, EBLM J0555-57Ab, that is roughly the same size as Saturn, located 600 light-years away from us.
If EBLM J0555-57Ab were any smaller, it would lack the internal pressure necessary for nuclear fusion to take place. As we discussed earlier, nuclear fusion is the process that generates the heat and light that stars emit. This star's size is perfectly suited to meet the minimum mass threshold required for nuclear fusion. If it were any smaller, it would have been classified as a brown dwarf—a type of failed star that doesn't have enough mass for gravity to initiate nuclear fusion.
