Labs / Astronomy
Stellar Wobble Detector
You can't see the planet, but you can catch the star it drags around. As the star circles the shared center of mass, its light shifts blue then red, and each measurement drops a point onto the phased radial-velocity curve. Change the planet's mass and period, or drag the orbit to tilt your line of sight, and see how the wobble grows or vanishes.
vr 0.0 m/sK 87.6 m/sM sin i 1.93 M♃
What to try
- Tilt the system to nearly face-on. Why does the orbit still look fine while the velocity curve flattens to nothing?
- Double the planet's mass. Does the velocity amplitude K double, and does the spectral line swing further?
- Stretch the period out to hundreds of days. What happens to K, and why are long-period planets harder to detect this way?
- If M sin i is the smallest the planet could be, when is the true mass much larger than what you measure?
- Can two very different planets — one heavy and tilted, one light and edge-on — produce the exact same wobble?