Conceptual Objective 13 asks that I explain how stars are formed and how they produce energy in their cores by nuclear fusion. As usual, I will follow the explanation with a bit relating the objective to the article linked above.
Stars are formed by a surprisingly understandable process. Stars are formed by what is called a “cloud collapse”. In this process a molecular cloud (which is a cool cloud made up of complex molecules) begins to cave in on itself. It does this when “clumps” of molecules become large enough to overpower the minute gravitational pull of the molecules around them. When these loose molecule begin to put pressure on one another they begin to warm up and eventually create what is called a protostar – which is a clump of gas that will become a new star.
The protostar continues to gather mass by attracting materials and dust around it until it’s created enough pressure to have it’s core reach 10 million K, which allows hydrogen fusion to perform properly. The new star will become main sequence when the core becomes hot enough to emit enough energy so that it will balance the energy being released from the surface.
*image from https://phys.org/news/2017-04-image-accretion-disk-young-star.html . The image is that of a young star with an accretion disk surrounding it.
The article listed above talks about how scientists have been theorizing for a while about how the accretion disks that form around young stars act as food for the star to grow bigger. This has never been viewed, and therefore the theory has never been able to be put to the test until astronomers at the ALMA radio telescope in Chile did just that! The accretion disk is simply a disk of gas and other elements that remained around the star after it made the transition from protostar to main sequence. Now that scientists can view an example of this, they will be able to observe it and run experiments, view the results, and see if it is feasible to say that accretion disks are baby food for new stars.
As I’ve mentioned before, I love firsts in astronomy. The theory sounds plausible to me (a more-than-amateur astronomer) that a star would feed off the remaining dust surrounding it’s birth. With a gravitational pull much stronger than any force nearby it is bound to suck in a great amount of materials thus adding to it’s mass. Yet, I