What type of star is the Sun — it is a G2V or a yellow dwarf in the main sequence of a star’s life cycle? Our star is not a particularly abnormal or unusual type, and experts agree it will be here for another 5 or so billion years.
Our solar system is filled with a diverse array of planets, moons, asteroids, meteorites, and many other objects floating around in space. They are all composed of materials that could be dated back to the origins of our solar system. As we begin to venture into space, our curiosity about the solar system and its components increase.
“Concentrate all your thoughts upon the work at hand. The sun’s rays do not burn until brought to a focus.” — Alexander Graham Bell
We are constantly pondering about the existence of life on other planets or moons as we look to places like Europa or Mars. We want to know what resources lay dormant on other celestial bodies that we could use to advance our technologies. Perhaps, in all of this, we are trying to grasp the size and scale of a place that seems infinite and unimaginable.
While there may be one Earth and one Moon, there are many other planets and many other moons. While each moon or planet may have unique characteristics, they are not alone. Even Pluto, which was once a planet, is among other dwarf planets. The only unique celestial body in our solar system would be the Sun. it is the center of our solar system and keeps everything held together. Its origin was crucial for the development of our planet and the other planetary bodies around us. So, like everything else in the solar system, it is important that we understand our Sun.
What kind of star is the Sun?
- A yellow dwarf star within the main sequence or life cycle of stars.
The sun is 92.92 million miles away from the Earth and is the largest thing in our solar system. It would take 332,946 Earths to match the mass of the sun. Its gravitational force holds our solar system together and allows us to exists in stable orbits. The sun, along with everything else, formed about 4.5 billion years ago from giant clouds of gas and dust that formed the solar nebula. This nebula rotated and it eventually collapsed on itself because of the immense gravity it produced. This increased its rotation speed and flattened the nebula. Over 98% of the materials were pulled to the center and formed the sun while everything else formed the planets, moons, and more.
The sun, like other stars, is a giant ball of gas that has formed intricate layers, akin to Earth’s layers. The sun is very hot and we can even feel it from where we are on Earth. It illuminates the solar system and its light is one of the reasons that life can comfortably exist on earth. At its core, the sun is 27 million degrees Fahrenheit, which is perfect for thermonuclear fusion. The surface is only about 10,000°F.
“How glorious a greeting the sun gives the mountains!” — John Muir
Thermonuclear fusion is the process by which atoms combine to form larger atoms, in this case, hydrogen atoms form helium atoms. This process produces large amounts of energy that travels from the core to the outer layer and across the solar system, which produces the light and heat we detect. This movement of energy takes about 170,000 years to reach the surface. This process is something that humans are attempting to emulate because it creates large amounts of clean energy that could be used to power the world with little worry about nuclear wastes or fallouts.
The sun is relatively young at 4.5 billion years old because researchers estimate that it has another 6.5 billion years before it dies. When it does eventually die, the sun will expand and consume the closest planets, Mercury and Venus, with the potential of taking Earth as well. As it expands, it will eventually collapse on itself and become a white dwarf or black hole.
There are billions of stars that are scattered across the galaxy and much more that are scattered across the universe. Among them, the sun is classified as a yellow dwarf because of the color it emits and its small size compared to most stars. As classifications update and change, the sun’s classification is a bit more precise and informative of its place in the universe. The classification described here is the Harvard Spectral Classification, which was described by astronomer Anne Jump Cannon as a way to modernize and simplify the classification of stars.
Class O stars are the hottest and most luminous of the stars with temperatures of over 30,000K (53540.33°F). They have a somewhat blue color but are mainly in the ultraviolet range. They are the rarest of the class types and represent some of the largest stars in the galaxy. This is probably because they have a lot of fusion that is happening compared to smaller stars.
Class B stars are still quite hot and luminous with temperatures ranging from 10,000K to 30,000K (17,540°F to 53,540°F). They also have a blue color. Similar to the class o, class b stars also have high levels of fusion. The consequence of this is that they die more quickly compared to the other classes.
Class A stars radiate light ranging from blues to whites, which white coloring more prominent. They have a considerably lower temperature compared to the O and B classes, indicating a lower level of fusion. These stars are some of the most common stars that are seen across the galaxy compared to the frequency of O or B class stars.
“Look up at the stars and not down at your feet. Try to make sense of what you see, and wonder about what makes the universe exist. Be curious.” — Stephen Hawking
Class F stars are primarily white because they contain a temperature range low enough to exclude the blue or ultraviolet light. They are found in every 1 out of 33 stars in our galaxy. This makes them more common than higher temperature classes.
Class G stars are usually white to yellow in color and not as bright as its higher temperature sisters. These represent 1 out of every 13 stars in the galaxy. The class G stars include the Sun. The sun characterized as a G2V star because every class has further classifications. The surface temperature of our sun is 10,000°F, which is about 5810K.
Class K stars are generally yellow to orange and smaller than preceding stars. They are about every 1 in 8 stars found. The last classification for this list is the class M stars, which have the lowest color and are least luminous. They are the most common stars found in the galaxy, representing over 76% of stars.
As mentioned, every classification has further classifications to make it more complex and include the nuances that exist within in class. As we study the galaxy and the universe, these classifications are forced to change. Just as previous classifications changed to modern ones, like this one, the modern ones will also face changes. Already there are classifications for brown dwarf stars and white dwarfs.