Eli5: how can they tell the composition, mass etc of planets in other solar systems?

Question

For example in they found a planet called “55 Cancri e” which is believed to have a diamond core and its 40 light years away.

Or

A planet called “HD 149026b” which has a temperature of 2,000C and is approximately 250 light years away.

How do they work out this information from so far away?

In: Physics

Answer 1

You know how Sherlock Holmes can walk into a crime scene, look at it really hard, from plenty of angles, and start telling you about what time the murderer woke up that morning, that he’s a tall black haired fella with a stutter and he’s a coffee drinker?

That’s what astronomers do. They can’t take an atmospheric sample and run tests on it, but there are clues that, when put together and correlated, can tell you an awful lot.