8.4 Io, one of the satellites of Jupiter, has an orbital period of 1.769 days and the radius of the orbit is 4.22 × 108 m. Show that the mass of Jupiter is about one-thousandth that of the sun.

Orbital period ofI0,
TIo=1.769days×24×60×60 s

Orbital radius of Io,
RIo=4.22×108M

Satellite Iois revolving around the Jupiter

Mass of the latter is given by the relation:

MJ=4π2R3TIo2                                         ...(i)

Where,

MJ= Mass of Jupiter

G = Universal gravitational constant

 

The orbital radius of the Earth,

Te=365.25 days=365.25×24×60×60 s

The orbital radius of the Earth,

Re=1 AU=1.496×1011 m

Mass of sun is given as:

Ms=4π2R3GTe2                                   ...(ii)
From i and ii,
MsMJ=4π2Re3GTe2×GTIo24π2RIo3=Re3RIo×TIo2Te2
=1.769×24×60×60365.25×24×60×602×1.496×10114.22×1083
=1045.04
=1000 Approx.

 MsMJ=1000
 Ms=1000×MJ