Space & astronomy · the experiment
Find the two rings
Around WD J1328−1450, every calcium line has four peaks. Place the gas rings that draw them yourself, then check what would make them disappear.
1 · A spinning ring
Beginner
Why does a spinning ring of gas draw two peaks per line?
Here is the inner ring alone. Move its outer edge until its two peaks are 1,024 km/s apart, like the measured ones.
2 · The second ring
Intermediate
The inner ring's peaks are 1,024 km/s apart, the outer ring's 420 km/s. How many times further from the star does the gas drawing the latter orbit?
Add the outer ring, which starts at 0.54 R☉. Move its outer edge until its peaks are 420 km/s apart.
3 · And without a gap?
Intermediate
Replace the two rings with a single disc, from 0.14 to 1.93 R☉, growing fainter outwards. How many peaks per line?
4 · Seen face-on
Expert
We see this double disc nearly edge-on, tilted at 77°. Imagine it seen exactly face-on. What would each line become?
Rings found
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