Question

In 1996, astronomers discovered an icy object beyond Pluto that was given the designation 1996 TL 66. It has a semimajor axis of 84 AU. What is its orbital period according to Kepler’s third law?

Answer 1

Answer:

772.65 years.  

Explanation:

Semi major axis = R = 84 AU = 1.257 × 10¹³ m

According to the 3rd law of Kepler, T² =  4 π² R³ / GM

Here R is the semi major axis. G = 6.67 × 10⁻¹¹ SI units.

M is the mass of the  Sun  = 1.98 x 10³⁰ kg

T² =    4 (3.14)³ (1.257 × 10¹³ )³÷ (6.67 × 10⁻¹¹)(1.98 x 10³⁰)

  ⇒  Time period  =  T = 2.44 x 10¹⁰ seconds

1 s = 3.17 × 10⁻⁸ years

Converting the seconds to years, T = 772.65 years.