Question

Model how low mass stars become white dwarves. Draw a picture. a) Draw the picture b) Explain in words c) Provide equations d) Skip

Answer 1

Low mass stars evolve into white dwarves through a series of stages. In the initial phase, the star fuses hydrogen into helium in its core, releasing energy. As the hydrogen supply depletes, the star expands into a red giant. Eventually, it sheds its outer layers, forming a planetary nebula. The remaining core, composed mostly of carbon and oxygen, becomes a white dwarf—a dense, Earth-sized remnant. The evolutionary process involves several key steps. First, hydrogen fusion sustains the star, leading to a red giant phase. Subsequently, the outer layers are expelled, creating a planetary nebula. The core contracts due to gravitational forces, resulting in a hot and dense white dwarf.

Step-by-step explanation:

a) The drawing represents the stages of a low mass star evolving into a white dwarf. It starts with a main sequence star undergoing hydrogen fusion, progresses to the red giant phase, and concludes with the formation of a white dwarf surrounded by a planetary nebula.

b) The star's journey begins with hydrogen fusion, sustaining it as a main sequence star. Depletion of hydrogen leads to the expansion into a red giant. The shedding of outer layers results in the formation of a planetary nebula, leaving behind the dense core that becomes a white dwarf.

c) The equations involve nuclear fusion reactions within the star, such as the proton-proton chain or CNO cycle. However, the white dwarf stage is characterized by the absence of fusion, making relevant equations focus on gravitational collapse and electron degeneracy pressure.

Answer 2

Model how low mass stars

Step-by-step explanation:

Low mass stars, like our Sun, undergo a series of stages leading to their transformation into white dwarves. As these stars exhaust their nuclear fuel, they enter the final stages of their life cycle. During this phase, they become red giants through a process of hydrogen shell burning and helium core contraction. Subsequently, they shed their outer layers, forming a planetary nebula, leaving behind the core composed of mostly carbon and oxygen.

This core, now referred to as a white dwarf, is supported by electron degeneracy pressure, a consequence of quantum mechanics. When the star's nuclear fusion ceases, gravity compresses the core until the electrons are forced into high-density states. This causes them to exert a pressure that counteracts gravitational collapse, preventing further compression.

The Chandrasekhar limit, roughly 1.4 times the mass of our Sun, determines the maximum mass a white dwarf can attain. Exceeding this limit can lead to a catastrophic event known as a Type Ia supernova.

The equation that helps understand this process is the Chandrasekhar limit equation:
`\( M_{\text{Ch}} = \frac{{3 * \pi}}{{√(32 * G)}} * \left(\frac{{h}}{{m_{\text{H}}}}\right)^3 \), where \( M_{\text{Ch}} \) is the Chandrasekhar mass limit, \( G \) is the gravitational constant, \( h \) is Planck's constant, and \( m_{\text{H}} \) is the mass of a hydrogen atom.`

This entire process signifies the final evolutionary stage of low mass stars, culminating in the formation of a white dwarf—a dense, Earth-sized object that gradually cools over billions of years.