Stellar Evolution and Remnants

1.44M☉

It can be used to determine the star's spectral class

A photon with a specific wavelength

<p>3M☉</p> Signup and view all the answers

<p>Discrete and negative</p> Signup and view all the answers

<p>External energy input, e.g. heat or absorption of a photon</p> Signup and view all the answers

<p>The negative sign represents the energy required to remove the electron from the atom.</p> Signup and view all the answers

<p>Each element produces a unique emission line spectrum due to the unique set of energy levels associated with its electrons.</p> Signup and view all the answers

<p>Emission line spectra appear as a series of coloured lines, while absorption line spectra appear as a series of dark lines against a continuous spectrum.</p> Signup and view all the answers

<p>The formula is E = hc/λ, where E is the energy, h is the Planck constant, c is the speed of light, and λ is the wavelength of the photon.</p> Signup and view all the answers

<p>The energy released is the difference between the initial energy level of the electron and the final energy level of the photon, and this energy corresponds to a specific wavelength.</p> Signup and view all the answers

<p>Transitions between different energy levels produce photons with different wavelengths.</p> Signup and view all the answers

<p>The peak wavelength is inversely proportional to the temperature of the object.</p> Signup and view all the answers

<p>λmax ∝ 1 / T, or λmax T = 2.9 x 10^(-3) mK</p> Signup and view all the answers

<p>The luminosity is proportional to the fourth power of its absolute temperature.</p> Signup and view all the answers

<p>L ∝ 4πr^2 T^4, or L = 4πr^2 T^4 σ (where σ is Stefan's constant, 5.67 x 10^(-8) Wm^-2 K^-4)</p> Signup and view all the answers

<p>It is essential to use absolute temperatures in Kelvin to avoid errors in the calculations, as the temperatures are often given in Centigrade.</p> Signup and view all the answers

<p>The absolute temperature and radius of the star can be determined using Wien's law and Stefan's law.</p> Signup and view all the answers

<p>The Doppler Effect shifts the position of spectral lines, allowing us to determine the relative speed of a star using the shift in wavelength from a hydrogen emission spectrum.</p> Signup and view all the answers

<p>The Doppler equation (∆𝜆 𝑣 = 𝜆 𝑐) is used to determine the relative speed of a star using the shift in wavelength from a hydrogen emission spectrum.</p> Signup and view all the answers

<p>The recessional velocity of a galaxy is proportional to its distance from Earth, as described by the equation 𝑉 = 𝐻+ 𝑑.</p> Signup and view all the answers

<p>The redshift of light from distant galaxies suggests that the galaxies are moving away from Earth, providing evidence for the expanding universe model.</p> Signup and view all the answers

<p>The Hubble constant (67.8 kms-1Mpc-1) is a key factor in the equation 𝑉 = 𝐻+ 𝑑, describing the relationship between the recessional velocity of a galaxy and its distance from Earth.</p> Signup and view all the answers

<p>The expanding universe model suggests that the fabric of space and time is expanding, and any point in the universe is moving away from any other point.</p> Signup and view all the answers

<p>The distance of a galaxy from Earth is directly proportional to its speed.</p> Signup and view all the answers

<p>14 billion years</p> Signup and view all the answers

<p>The Big Bang theory is an attempt to describe the origins and development of the early universe. According to this theory, all objects were initially contained in a singularity, which suddenly expanded outwards.</p> Signup and view all the answers

<p>Hubble's Law, which shows the universe is expanding, and the microwave background radiation</p> Signup and view all the answers

<p>The Big Bang theory is not considered a reliable scientific theory because there is no experimental evidence to support it - we cannot recreate the initial conditions of the Big Bang.</p> Signup and view all the answers

<p>The microwave background radiation is thought to be a remnant of the initial high-energy gamma photons, which were stretched into the microwave region as the universe expanded.</p> Signup and view all the answers

<p>Gigantic clouds of dust and gas</p> Signup and view all the answers

<p>Spherical</p> Signup and view all the answers

<p>Eccentric elliptical</p> Signup and view all the answers

<p>100 billion</p> Signup and view all the answers

<p>A protostar</p> Signup and view all the answers

<p>Protons and electrons combine to form neutrons, producing a dense neutron star.</p> Signup and view all the answers

<p>It shows the stellar luminosity of a star against its temperature, allowing us to determine the star's spectral class.</p> Signup and view all the answers

<p>It becomes 'excited' and requires the input of external energy, such as heat or absorption of a photon.</p> Signup and view all the answers

<p>They are discrete and negative, with the ground state being the most negative.</p> Signup and view all the answers

<p>It releases energy in the form of a photon with a specific wavelength.</p> Signup and view all the answers

<p>Nuclear fusion</p> Signup and view all the answers

<p>The main phase is when a star remains in stable equilibrium, maintained by the balance between gravitational forces and radiation pressure from photons and gas pressure from nuclei in the core.</p> Signup and view all the answers

<p>The mass of the star, with larger stars being hotter and undergoing fusion faster, resulting in a shorter main phase.</p> Signup and view all the answers

<p>The star begins to collapse inwards and evolves into a red giant.</p> Signup and view all the answers

<p>Between 0.5M and 10M, where M is the solar mass (1.99 x 10^30 kg).</p> Signup and view all the answers