Prior to this conceptual objective, we touched basis on the formation of the star when we covered the nature of the solar system. Stars actually start out as nebulas, clouds of gas and dust. Overtime gravity acts on it and forces the cloud to collapse and perpetuate the “clumping” of molecules as the temperature rises eventually giving us our star.
However, in this conceptual objective, we dove a little deeper and looked at the procession of nuclear fusion of a star. With nuclear fusion, we’re also able to identify the longevity of a star because there is a connection between a star’s lifespan and its rate of nuclear fusion.
In, “TRAPPIST-1 IS SHOWING A BIT TOO MUCH FLARE,” the article mentions quite a few interesting facts about the distant red dwarf star. Previously, there have been speculations on whether the 7 Earth-sized planets that orbit the red dwarf possessed the ability to sustain life. However, now it seems that by looking at the properties of the star it the planets mostly likely won’t be able to.
The world is a complex place, so when it comes to the universe what else can we expect. The article states that stars like the Trappist-1 are “intriguing targets in the search for habitable worlds” but the Trappist-1 itself is “too volatile for life to exist on its planets”. Why is that?
Star Trappist-1 was formed just liked any other star. It began as a molecular cloud in the interstellar medium. The cloud is cold and dense where atoms can combine and form molecules. Then, typically with the help of a supernova shockwave, the molecular cloud begins to collapse, gravity pulls the gas and molecules together towards the densest region. This is where molecules begin to clump together and the temperature of the cloud begins to rise. The cloud contracts and the temperature rise because the central region (is called a protostar) become dense enough to trap infrared radiation; heat can no longer escape. Temperature and pressure build within the cloud and begins acting against the gravitational force that is pushing the cloud to contract. Gravity is still the stronger force at this point and until temperature/pressure is high enough to start nuclear fusion, the to-be star remains in its protostar state. When everything in the cloud is packed and pulled down so tightly together, the process of nuclear fusion begins and this is when the to-be star transitions from a protostar to a newborn star.
Nuclear fusion occurs throughout the lifetime of a star; it is the energy output of a star. Hydrogen atoms are combined together to form helium atoms through the proton-proton cycle. When this fusion occurs, light/energy is emitted. The energy given off during the fusion acts as an outward pressure to balance out the inward gravitational collapse of the material. The star will cease to collapse when it reaches hydrostatic equilibrium, the balance between light radiation and gravity, thus creating a main sequence star, like the Trappist-1.
According to the article, “red dwarfs are much dimmer than our Sun, but they also last much longer” which means that their lifetime will be “measured in trillions of years, not billions”. This is because we learned in a lecture tutorial low-mass stars (red dwarfs) live longer than high-mass stars. The reason being is that the rate of nuclear fusion occurs at a slower rate than it would be in high-mass stars.
It was really interesting to read this article because prior to this conceptual objective, I’ve read articles that reported on the Trappist-1 solar system. At that particular time, astronomers were speculating on the possibility of life, like I mentioned above. But now that they looked into Trappist-1’s properties and concluded that it’s certainly not possible for the planets of that solar system to sustain life, it was really fascinating to see them discover this fact, step by step. I really enjoyed reading and updating myself on the Trappist-1 solar system and learning more about the star itself.
It’s important to know the life of stars because their properties and behavior directly connect to us. As previously mentioned, stars like red dwarfs with long life are “intriguing targets in the search for habitable worlds”. Since we’re so eager to find new signs of life, it’s important to understand the formation of stars and their lifetime because they play a crucial role in future discoveries.