Chapter 11, Problem 11A.6E

Interpretation Introduction

Interpretation:

The speed of recession and surface temperature of the star has to be calculated.

Concept Introduction:

Speed of recession can be calculated using the formula given below.

$\frac{{\lambda }^{\text{'}}-\lambda }{\lambda }=\frac{v}{c}$

Where,

    $\begin{array}{l}{\lambda }^{\text{'}}=dopplershiftedwavelength\\ \lambda =wavelengthemitted\\ v=velocityofstarwithrespecttheobserveronearth\\ c=velocityoflight\end{array}$

The surface temperature of the star can be calculated using Wien’s law, because a star can be considered as a black body.  And the equation for the law is given below.

${\lambda }_{max}=\frac{b}{T}$

Given,

    $\begin{array}{c}{\lambda }_{\max }=wavelength\\ b=Wien\text{'}sdisplacementcons\tan t\\ T=temperatureinKelvinscale\end{array}$