What did you change in the model?
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.
Labs / Astronomy / Stellar Wobble Detector
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.
Why it matters
Why explore this?
Astronomy uses patterns in light and motion to explain objects we cannot touch directly. This model lets you change one part of a space system and see what the evidence would look like.
Explore
Try the model
vr 0.0 m/sK 87.6 m/sM sin i 1.93 M♃
Investigate
Questions to test
Predict first, try it in the model, then use what you observe to answer.
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?
Explain
Make sense of what happened
Look for a cause-and-effect rule: what did you change, what responded, and what stayed the same? Astronomers use those patterns to infer how distant systems work.
Check
Before you leave
What visible evidence changed?
What rule could explain that change?
If you can answer all three using evidence from the model, you understand the main idea. If not, return to Explore and change one setting at a time.