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Given the mass of a star, determine Kepler's constant.

  • Thread starter Solidearth
  • Start date
  • #1

Homework Statement


"The mass of a star is 4.85x10^29kg. In scientific notation, Kepler's constant for that star is bx10^w s2/m3. the value of b is_____."


Homework Equations



K=T2/r3

The Attempt at a Solution


This problem is very tough. I first assumed that K would be 0 because the star has no satellites, and therefore is experiencing linear motion, not circular motion. To my dismay however, the answer is indeed 3 digits and Kstar> 0.
The greatest obstacle is how am I to derive the period and semi major axis of its orbit, if i am only given the star's mass???!!!
Any insights into this problem are helpful.
Thanks!
 

Answers and Replies

  • #2
LowlyPion
Homework Helper
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4

Homework Statement


"The mass of a star is 4.85x10^29kg. In scientific notation, Kepler's constant for that star is bx10^w s2/m3. the value of b is_____."

Homework Equations



K=T2/r3

The Attempt at a Solution


This problem is very tough. I first assumed that K would be 0 because the star has no satellites, and therefore is experiencing linear motion, not circular motion. To my dismay however, the answer is indeed 3 digits and Kstar> 0.
The greatest obstacle is how am I to derive the period and semi major axis of its orbit, if i am only given the star's mass???!!!
Any insights into this problem are helpful.
Thanks!
Welcome to PF.

If K = T2/ a3

Can't you determine K directly from:

T = 2π*(a3/GM)1/2

Yielding

K = 4π2/(G*M)
 

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