What is the first event that happens to a star with roughly...

Name: Problem 2, Chapter 22: Astronomy
Uploaded: 2020-10-12T21:35:03-08:00
Duration: 5 min 7 s
Channel: Sarah Mccrumb
Description: What is the first event that happens to a star with roughly the mass of our Sun that exhausts the hydrogen in its core and stops the generation of energy by the nuclear fusion of hydrogen to helium? Describe the sequence of events that the star undergoes.

What is the first event that happens to a star with roughly the mass of our Sun that exhausts the hydrogen in its core and stops the generation of energy by the nuclear fusion of hydrogen to helium? Describe the sequence of events that the star undergoes.

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Key Concepts

Hydrogen Exhaustion

This concept refers to the point at which a star’s central hydrogen fuel is depleted, causing it to lose the steady energy generation that sustains it during the main sequence phase. This mark is critical in stellar evolution as it signals the beginning of a series of structural adjustments inside the star.

Core Contraction

After hydrogen in the core is exhausted, gravitational forces cause the core to contract. This contraction raises the core’s temperature and pressure, an essential precursor to subsequent stages of fusion that occur in layers surrounding the core.

Hydrogen Shell Burning

Once the core contracts and heats up, fusion reactions restart in a shell around the inert helium core. This hydrogen shell burning produces energy that compensates for the loss of core fusion, significantly impacting the star’s energy output and structural evolution.

Red Giant Phase

The energy released from hydrogen shell burning causes the outer layers of the star to expand considerably, cooling as they spread out. This marks the transformation of the star into a red giant, a distinct phase characterized by a large, luminous, and cooler envelope compared to its main sequence configuration.

Transcript

0:00 Hi, everybody.

00:01 So here is, it's asking us, what is the first event that happens to a star with the roughly mass of our sun that exhausts the hydrogen in its core and stops a generation of energy by the nuclear fusion of hydrogen to helium? describe the secrets of events of the star on goes.

00:18 Okay, so the first thing that happens to a star with roughly the mass of a sun exhausts is hydrogen in the core and stops the generation of energy by nucleo fusion to helium and starts shrinking.

00:30 So the star will shrink due to the gravity.

00:42 And so when the star starts to hygiene, its core of nucleate, the gravitation force becomes light.

00:52 So, and then gravitation equals less, okay? and the core of the star begins to shrink, and then the core shrinks, okay, due to gravity, and the core is full with helium.

01:14 So core is full of helium.

01:23 Okay.

01:24 And there is not enough temperature to fuse helium.

01:27 And so we have not enough temperature to fuse helium.

01:39 Okay.

01:40 And as the core contracts, material falls downward.

01:43 So then the material falls downward.

01:56 As, and we'll put as here, a little better, as contraction begins.

02:06 And let me rewrite that t here, so that's kind of a weird t.

02:13 There we go...