The universe is full of amazing and fascinating objects, but few are as impressive as the stars. Stars are immense balls of burning plasma that produce light and heat through nuclear fusion. They come in different sizes, colors, and temperatures, but some of them are truly gigantic.
In this article, we will explore the top 10 biggest stars in the universe in 2024, based on their estimated radius. We will also learn some interesting facts about these stars, such as their distance from Earth, their mass, their luminosity, and their lifespan.
What is a star’s radius?
Before we dive into the list, let’s first understand what we mean by a star’s radius. A star’s radius is the distance from its center to its surface. However, unlike planets, stars have no distinct surface with which to form an “edge” for measurements. Instead, astronomers use various methods to estimate the radius of a star, such as stellar interferometry, lunar occultations, eclipsing binaries, or theoretical models. These methods can have different levels of accuracy and uncertainty, depending on the star’s characteristics and the available data.
Therefore, the values for stellar radii are not exact and may change over time as new observations and discoveries are made. The values we will use in this article are based on the latest research and data available in 2024, but they may be revised in the future.
How big is our Sun compared to other stars?
Our Sun is the star that we are most familiar with, as it is the source of life and energy for our planet. It is also the closest star to Earth, at a distance of about 150 million kilometers (93 million miles). But how big is our Sun compared to other stars in the universe?
The Sun has a radius of about 695,700 kilometers (432,300 miles), which is equivalent to 109 times the radius of Earth. That means that about 1.3 million Earths could fit inside the Sun. However, the Sun is not even a medium-sized star in comparison to other more massive stars. In fact, the Sun is classified as a yellow dwarf, which is a type of low-mass star that has a relatively low luminosity and a long lifespan.
The Sun is also much smaller than the stars we will see in this list, which are mostly red supergiants or red hypergiants. These are types of high-mass stars that have very high luminosity and a short lifespan. They also have very large radii, ranging from hundreds to thousands of times the radius of the Sun.
Top 10 biggest stars in the universe in 2024
Now that we have some background information, let’s start with the countdown of the top 10 biggest stars in the universe in 2024, from the smallest to the largest.
10. Betelgeuse
Betelgeuse is a red supergiant star located in the constellation of Orion, about 640 light-years from Earth. It is one of the brightest stars in the night sky, and it is easily recognizable by its reddish-orange color. Betelgeuse has a radius of about 950 to 1,200 times the radius of the Sun, which means that if it replaced the Sun in our solar system, it would extend beyond the orbit of Jupiter. Betelgeuse is also very unstable and variable, as it undergoes periodic changes in brightness and size. Betelgeuse is expected to explode as a supernova in the near future, which could be visible from Earth even during the day.
9. VY Canis Majoris
VY Canis Majoris is a red hypergiant star located in the constellation of Canis Major, about 3,900 light-years from Earth. It is one of the most luminous stars in the Milky Way galaxy, emitting about 500,000 times more energy than the Sun. VY Canis Majoris has a radius of about 1,800 to 2,100 times the radius of the Sun, which means that if it replaced the Sun in our solar system, it would reach nearly to the orbit of Saturn. VY Canis Majoris is also surrounded by a complex and asymmetric nebula, which is formed by the strong stellar winds that blow away the outer layers of the star.
8. RW Cephei
RW Cephei is a red supergiant star located in the constellation of Cepheus, about 11,500 light-years from Earth. It is one of the most distant stars in this list, and it is also one of the most variable. RW Cephei has a radius of about 1,535 to 2,755 times the radius of the Sun, which means that if it replaced the Sun in our solar system, it would reach beyond the orbit of Saturn. RW Cephei is also very massive, with an estimated mass of about 40 to 60 times the mass of the Sun. RW Cephei is likely to end its life as a supernova or a black hole.
7. V345 Cephei
V345 Cephei is a red supergiant star located in the constellation of Cepheus, about 9,000 light-years from Earth. It is one of the most obscure stars in this list, as it is very faint and difficult to observe. V345 Cephei has a radius of about 1,970 to 2,770 times the radius of the Sun, which means that if it replaced the Sun in our solar system, it would reach beyond the orbit of Saturn. V345 Cephei is also very luminous, with an estimated luminosity of about 300,000 times that of the Sun. V345 Cephei is expected to explode as a supernova in the distant future.
6. WOH G64
WOH G64 is a red supergiant star located in the Large Magellanic Cloud, a satellite galaxy of the Milky Way, about 163,000 light-years from Earth. It is the only star in this list that is not located in our own galaxy, and it is also the most distant star that has a direct measurement of its radius. WOH G64 has a radius of about 1,540 to 2,860 times the radius of the Sun, which means that if it replaced the Sun in our solar system, it would reach beyond the orbit of Saturn. WOH G64 is also surrounded by a thick dust shell, which is formed by the strong stellar winds that eject material from the star.
5. VV Cephei A
VV Cephei A is a red supergiant star located in the constellation of Cepheus, about 4,900 light-years from Earth. It is part of a binary system with a blue main-sequence star called VV Cephei B, which orbits around it every 20 years. VV Cephei A has a radius of about 1,050 to 1,900 times the radius of the Sun, which means that if it replaced the Sun in our solar system, it would extend beyond the orbit of Jupiter. VV Cephei A is also very massive, with an estimated mass of about 25 to 40 times the mass of the Sun. VV Cephei A is likely to end its life as a supernova or a black hole.
4. UY Scuti
UY Scuti is a red supergiant star located in the constellation of Scutum, about 5,200 light-years from Earth. It is the current record holder for the largest star in the universe, based on the most accurate measurement of its radius. UY Scuti has a radius of about 1,708 times the radius of the Sun, which means that if it replaced the Sun in our solar system, it would extend beyond the orbit of Jupiter. UY Scuti is also very luminous, with an estimated luminosity of about 340,000 times that of the Sun. UY Scuti is expected to explode as a supernova or a black hole in the near future.
3. NML Cygni
NML Cygni is a red hypergiant star located in the constellation of Cygnus, about 5,300 light-years from Earth. It is one of the most luminous stars in the Milky Way galaxy, emitting about 560,000 times more energy than the Sun. NML Cygni has a radius of about 1,650 to 1,835 times the radius of the Sun, which means that if it replaced the Sun in our solar system, it would extend beyond the orbit of Jupiter. NML Cygni is also surrounded by a complex and asymmetric nebula, which is formed by the strong stellar winds that blow away the outer layers of the star.
2. KY Cygni
KY Cygni is a red supergiant star located in the constellation of Cygnus, about 5,000 light-years from Earth. It is one of the most massive stars in the Milky Way galaxy, with an estimated mass of about 25 to 40 times the mass of the Sun. KY Cygni has a radius of about 1,420 to 2,850 times the radius of the Sun, which means that if it replaced the Sun in our solar system, it would reach nearly to the orbit of Saturn. KY Cygni is also very luminous, with an estimated luminosity of about 300,000 times that of the Sun. KY Cygni is expected to explode as a supernova or a black hole in the near future.
1. V354 Cephei
V354 Cephei is a red supergiant star located in the constellation of Cepheus, about 9,000 light-years from Earth. It is the biggest star in the universe in 2024, based on the most recent measurement of its radius. V354 Cephei has a radius of about 1,520 to 3,000 times the radius of the Sun, which means that if it replaced the Sun in our solar system, it would reach nearly to the orbit of Uranus. V354 Cephei is also very luminous, with an estimated luminosity of about 320,000 times that of the Sun. V354 Cephei is expected to explode as a supernova or a black hole in the distant future.
Conclusion
We have seen the top 10 biggest stars in the universe in 2024, and we have learned some amazing facts about these colossal objects. These stars are truly awe-inspiring, as they demonstrate the diversity and complexity of the universe. They also remind us of how small and fragile we are in comparison to the cosmic scale. However, these stars are also very rare and short-lived, as they consume their fuel rapidly and end their lives in spectacular explosions. Therefore, we should appreciate their beauty and wonder while they still exist.
Most asked questions and answers
Here are some of the most common questions and answers related to the topic of the biggest stars in the universe.
- Q: What is the smallest star in the universe?
- A: The smallest stars in the universe are called red dwarfs, which have radii of about 0.1 to 0.2 times the radius of the Sun. The smallest known red dwarf is EBLM J0555-57Ab, which has a radius of about 0.08 times the radius of the Sun.
- Q: What is the most massive star in the universe?
- A: The most massive stars in the universe are called blue hypergiants, which have masses of about 50 to 200 times the mass of the Sun. The most massive known star is R136a1, which has a mass of about 315 times the mass of the Sun.
- Q: What is the most luminous star in the universe?
- A: The most luminous stars in the universe are called Wolf-Rayet stars, which have luminosities of about 1 million to 10 million times that of the Sun. The most luminous known star is R136a1, which has a luminosity of about 8.7 million times that of the Sun.
- Q: What is the hottest star in the universe?
- A: The hottest stars in the universe are called blue hypergiants, which have surface temperatures of about 20,000 to 50,000 K. The hottest known star is WR 102, which has a surface temperature of about 210,000 K.
- Q: What is the coldest star in the universe?
- A: The coldest stars in the universe are called brown dwarfs, which have surface temperatures of about 300 to 2,500 K. The coldest known star is WISE 0855−0714, which has a surface temperature of about 250 K.
- Q: What is the oldest star in the universe?
- A: The oldest stars in the universe are called Population III stars, which are the first generation of stars that formed after the Big Bang. The oldest known star is SMSS J031300.36-670839.3, which is about 13.6 billion years old.
- Q: What is the youngest star in the universe?
- A: The youngest stars in the universe are called protostars, which are the early stages of star formation. The youngest known star is L1448 IRS2E, which is about 100,000 years old.
- Q: How do stars die?
- A: Stars die when they run out of nuclear fuel in their cores. Depending on their mass, stars can die in different ways. Low-mass stars like the Sun will swell into red giants and then shed their outer layers as planetary nebulae, leaving behind white dwarfs. High-mass stars will explode as supernovae, leaving behind neutron stars or black holes.
- Q: What is a supernova?
- A: A supernova is a powerful explosion that occurs when a massive star collapses under its own gravity. A supernova can release more energy than the Sun will produce in its entire lifetime, and it can outshine an entire galaxy for a brief period of time. A supernova can also produce heavy elements and cosmic rays, which are essential for the formation of planets and life.
- Q: What is a black hole?
- A: A black hole is a region of space where gravity is so strong that nothing, not even light, can escape. A black hole is formed when a very massive star collapses into a point of infinite density and zero volume, called a singularity. A black hole has a boundary called an event horizon, which marks the point of no return for anything that falls into it. A black hole can also distort space and time around it, creating phenomena such as gravitational lensing and time dilation.