Goddamn

Favorite color?

It changes almost every day ~ but I’ve always really liked purple :D

THE LIFE OF A STAR: CLASSIFICATION

In order to understand the life of a star, we must understand star classification.

        And there are SO many different ways to classify a star.

        In star classification, understanding the relationship between color and temperature is crucial. The greater the temperature of the star, the bluer they are (at their hottest, around 50,000 degrees Celcius), while red stars are cooler (at their coolest, around 3,000 degrees Celcius). This occurs on a wide range (fun fact: stars only come in red, orange, yellow, white, and blue, because stars are approximately something called a "black body"). For example, our Sun is a yellow star with a surface temperature of 5,500 degrees Celcius (The Life of a Star).

        But why is this so? In order to understand that, I'm going to tell you about how stars live at all. This is what will determine the entire life of a star - something we'll be focusing on throughout this series. Two words: nuclear fusion.

        Nuclear fusion is "a reaction in which two or more atomic nuclei are combined to form one or more different atomic nuclei and subatomic particles (neutrons or protons). The difference in mass between the reactants and products is manifested as either the release or absorption of energy." (Wikipedia) And this is where nuclear fusion gets REALLY important to stars. Throughout their lives, stars undergo nuclear fusion in their core. This is mostly in the form of fusing two or more hydrogen atoms into one or more helium atoms. This releases energy in the form of light (the pressure of nuclear fusion in the core also prevents the star from collapsing under the weight of gravity, something we'll get to later). The energy transports to the surface of the star and then radiates at an "effective temperature." (Britannica) 

        Stars are different colors due to differing amounts of energy. This is best explained by Einstein's e=mc2 or the mass-energy equivalence. In other words, the more mass something has, the more energy, and vice versa. Stars with greater mass undergo more nuclear fusion - and as such - emit more energy/temperature. And so, the bigger the star, the greater the temperature, the bluer the star; and the smaller the star, the lower the temperature, the redder the star (Universe Today). Another way to think about this is this: the hotter something is, the shorter frequency of energy it emits. Blue light has a shorter frequency than red light, and so, higher energy/temperature stars are bluer.

        Another important classification of a star is its luminosity (or the brightness, or the magnitude of the star). (The Life of a Star)

        The most famous diagram classifying stars is the Herzsprung Russell Diagram, shown in this article's picture. The x-axis of the diagram shows surface temperature, hottest left, and coolest right. The y-axis shows brightness, brighter higher, and dimmer lower. There are main groups on the diagram. 

        Most stars fall in a long band stretching diagonally, starting in the upper left corner and ending in the right lower corner, this is called the main sequence. The main sequence shows stars which mostly use their life going through nuclear fusion. This process takes up most of a star's life. Most stars which are hotter and more luminous fall in the upper left corner of the main sequence and are blue in color. Most stars that have lower-masses are cooler, and redder falls in the lower right. Yellow stars like our Sun fall in the middle. 

         The group located in the lower-left corner are smaller, fainter, and bluer (hotter) and are called White Dwarfs. These stars are a result of a star like our Sun one day running out of Hydrogen.

          The group located right above the righter's main sequence is larger, cooler, brighter, and a more orange-red or red, are called Red Giants. They are also part of the dying process of a star like our sun. Above them in the upper right corner are Red Super Giants, massive, bright, cooler, and much more luminous. To the left of the Red Super Giants are similar stars which are just hotter and bluer and are called the Blue Super Giants.

        That explains the most famous star classifying diagram. The important thing to remember is the data on the chart is not what a star will be like it's whole life. A star's position on the chart will change like our Sun will one day do.

        In a ThoughtCo. article on the Hertzsprung Russell Diagram, Carolyn Collins Petersen wrote: "One thing to keep in mind is that the H-R diagram is not an evolutionary chart. At its heart, the diagram is simply a chart of stellar characteristics at a given time in their lives (and when we observed them). It can show us what stellar type a star can become, but it doesn't necessarily predict the changes in a star." ( The Hertzsprung-Russell Diagram and the Lives of Stars)

        And this will continue to be important in the next chapters. Stars don't just stay in the same position their entire lives: they change in their color, luminosity, and temperature. In this series, we'll be tracking how stars form, live and die - all dependent on these three factors - and nuclear fusion - again - super important :)

Previous -  Chapter 1: An Introduction

Next -  Chapter 3: Star Nurseries

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Accurate

Even though it’s possible the apple thing never happened.

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Thinking intensifies

OTHER PEOPLE: Oh no - that’s not good!

ME: Woah cool!!!!!!

Also, spaghettification here I come!!!

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Just so you guys know, the Galilean Moons aren’t Jupiter’s only moons. It has 79 confirmed moons.

Hey, at least they’re not all lonely.

Also, fun-fact, the Moon Europa is a big candidate for a “2nd Earth,” having an ocean under a shell of ice.

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Over the span of a few hours, I collected images of Jupiter and its Galilean Moons. I labelled each one and you can see them move in their orbits! 🪐🪐🪐

Taken by me (Michelle Park) using the Slooh Canary Two telescope on June 3rd, 2020.

That’s epic :o

Kennedy Space Center reopens on May 28th and I begged my parents to go but they don’t want to xD

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The first West Coast SpaceX launch captured by photographer Dylan Schwartz.

Goregous :O

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Comet Swan

What a cool illustration :D

It’s true though

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Art by Emanuele Fais

... why.

There are no aliens - so the only thing we could use this as is like a nuke - but that would destroy the entire Earth xD

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Looks like I’m getting a new wallpaper

It’s so beautiful ;(

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Sunset in the Kananaskis Valley, Alberta. [2853 x 3566] [oc] - Author: ProjectOxide on reddit