Describe two characteristics that can be determined about a star by analyzing the spectra of the star.

Effective temperature, Doppler velocity

Explanation:

Since star behave localy as a blackbody, Wíen's displacement law can be use in order to determine its effective temperature. From the spectrum it will be take the wavelength at which is the peak of emission greater in the continuum

Then, the maximum peak of emission () will be replace in the next equation of the Wien's displacement law:

(1)

Where T is the effective temperature of the star.

Spectral lines will be shifted to the blue part of the spectrum if the source of the observed light is moving toward the observer, or to the red part of the spectrum when is moving away from the observer (that is known as the Doppler effect).

By using that shift in the spectral lines it can be determine the Doppler velocity.

 (2)

Where is the wavelength shift, is the wavelength at rest, v is the velocity of the source and c is the speed of light.

grav force prop 1/r squared 2r all squared is 4rsquared 1/4rsquared quartered