ASTROPHYSICS
Methods used to search for extrasolar planets
Lucky Ruangsiri
24.02.2016
Extrasolar planets are planets that revolves another star apart from our solar system. The human race has found nearly 2000 confirmed extrasolar planets by the year 2016, and this has fuelled the search for extra-terrestrial life as we scour the universe for anything out there. How do we discover these planets that are light years away from the earth?
An extrasolar planet detection technique is the Doppler technique, also known as the wobble method or the radial-velocity method. The influence of a planet’s gravitational pull on its parent star causes the star to wobble slightly, and this wobble influences the waves of light that a telescope can …show more content…
So why doesn’t a planet just get pulled into a star? Because the forces acting on the planet are balanced. The force that balances the gravitational force of the star is centripetal force, for which the equation is
Where m is mass, v is velocity, and r is the radius of the circle.
Newton’s first law of motion, the law of inertia, states that
“An object at rest will remain at rest unless acted on by an unbalanced force. An object in motion continues in motion with the same speed and in the same direction unless acted upon by an unbalanced force.”
Because the forces are balanced for the planet and the star, it continues with its circular motion, with the same speed in the same direction. Essentially, a planet continues to travel around a star because they cannot escape the gravity of the star at the velocity it is traveling, but is traveling fast enough to not get pulled into the star.
Therefore, Fc = Fg.
(mv^2)/r=(m_1 m_2)/r^2
This can be used to measure the velocity of a planet by rearranging to form v=√((Gm_1)/r) The influence of a planet’s gravitational pull on the star that they revolve around creates the Doppler effect, which can be detected by the Doppler
Methods used to search for extrasolar planets
Lucky Ruangsiri
24.02.2016
Extrasolar planets are planets that revolves another star apart from our solar system. The human race has found nearly 2000 confirmed extrasolar planets by the year 2016, and this has fuelled the search for extra-terrestrial life as we scour the universe for anything out there. How do we discover these planets that are light years away from the earth?
An extrasolar planet detection technique is the Doppler technique, also known as the wobble method or the radial-velocity method. The influence of a planet’s gravitational pull on its parent star causes the star to wobble slightly, and this wobble influences the waves of light that a telescope can …show more content…
So why doesn’t a planet just get pulled into a star? Because the forces acting on the planet are balanced. The force that balances the gravitational force of the star is centripetal force, for which the equation is
Where m is mass, v is velocity, and r is the radius of the circle.
Newton’s first law of motion, the law of inertia, states that
“An object at rest will remain at rest unless acted on by an unbalanced force. An object in motion continues in motion with the same speed and in the same direction unless acted upon by an unbalanced force.”
Because the forces are balanced for the planet and the star, it continues with its circular motion, with the same speed in the same direction. Essentially, a planet continues to travel around a star because they cannot escape the gravity of the star at the velocity it is traveling, but is traveling fast enough to not get pulled into the star.
Therefore, Fc = Fg.
(mv^2)/r=(m_1 m_2)/r^2
This can be used to measure the velocity of a planet by rearranging to form v=√((Gm_1)/r) The influence of a planet’s gravitational pull on the star that they revolve around creates the Doppler effect, which can be detected by the Doppler