Astrophysics 1 Midterm 1

What is Kepler’s first law?

Every planet moves in an elliptical orbit, with the sun at one of the two foci. 

What is Kepler’s third law?

P² is proportional to a³, aka the period squared is proportional to the semimajor axis cubed. Units are yrs and AU respectively.

What is Wien’s law?

The peak wavelength emitted is inversely proportional to its temperature. The hotter an object gets, the shorter the wavelengths it emits.

What is Stefan-Boltzmann law?

The total radiant heat energy emitted per unit surface area of a blackbody is directly proportional to T^4

What is the physical mechanism that forms spectral lines?

The lines form when electrons transition between different energy states. This is done by absorbing or emitting photons.

What is the energy of a photon?

E= h/f or E= hc/ lambda

How do we identify elements in the sun?

Spectroscopy, because different atoms produce different spectral lines.

What is the Doppler effect?

The change in perceived frequency because the source or observer is moving relative to the other.

Why is a larger telescope better than a smaller telescope?

Larger telescopes have more area to collect light, thus resulting in a higher resolution image. Also allows for further, fainter objects to be seen.

Which wavelength band yields the highest spatial resolution?

The panochromatic band, it captures a broad range of visible light.