You've just discovered a new X$-$ray binary, which we will call Hyp$-$X$1("$Hyp$"$ for hypothetical$).$ The system Hyp$-$X$1$ contains a bright, B$2$ mainsequence star orbiting an unseen companion. The separation of the stars is estimated to be $25$ million kilometers, and the orbital period of the visible star is $4$ days.

Part B

Part C

Determine the mass of the unseen companion. $($Hint: A main$-$sequence star with spectral type B $2$ has a mass of about $10M_{\text{S}\text{u}\text{n}}.)$

Express your answer as a multiple of Sun's mass to two significant figures.

View Available Hint$($s$)$

Hint $1.$ Hoe to approach the problem

Use the total mass of the system obtained via Newton's version of Kepler's third law and the approximate mass of the B$2$ star.

$M_{\text{u}\text{n}\text{s}\text{e}\text{e}\text{n}}=M_{\text{S}\text{u}\text{n}}$