Stellar atmosferas (radiative transfer equation)

What does de Saha equation describes?

• the ionization states of a particle gas

• The de-excitation of an electron from higher level to lower level

• the capture of an electron by an atom in a degenerate gas

• I do not know

What is degeneracy, g_i? (hint: think on the Boltzmann equation)

• I do not know

• it is described by the partition function.

• a combination of quantum states that have same energy

• atoms in a degenerate matter.

what is the bound-bound absorption?

• when an electron separates from the atom

• when an electron moves to a different energy level within the atom

• when an electron moves to a different level of another atom

• when the trajectory of an electron is change by absorving a photon

What is optical depth?

• a quantity related with the emissivity a medium has

• a specific wavelength range at the optical

• the number of mean free path a photon needs to travel certain distance?

• I do not know

what statement is correct?

• the smaller is the cross section of the particle, the larger is the opacity

• the larger is the cross section of the particle, the larger is the opacity

• the larger is the cross section of the particle, the smaller is the opacity

• no lo se

How is the rosseland mean opacity for scattering absorption?

• decreases with temeperature

• Constant

• increases with temperature

• no lo se

Which type of absoption dominates at temperatures 9000-10000K ?

• bound free: photoionization of hydrogen

• bound free: photoionization of helium

• bound free: photoionization of iron

• no lo se.

what is the equation which described how the electromagnetic radiation propagates in a medium under processes of absorption, scattering and emission?

• the radiative transfer equation

• Boltzmann equation

• Stefan-boltzmann equation

• The Planck function

What is the source function?

• the function that describes a gas in LTE

• I do not know

• intrinsic properties of a beam intensity that travels in the space

• describes de ratio of the emission and absorption

For the case of thermodynamic equilibrium of a medium, the source function is equal to the Planck function, S_λ = B_λ. How does the medium needs to be such that an observer receives the same Planck radiation?

• optically thin

• optically thick

• I do not know

• it does not matter