3 ms·

Couldn't any mass planet be going any speed at any distance around a star? I'm not sure why these factors would depend on mass.

• hugh_ 17y ago
  You're correct -- the orbital speed and path tell you nothing about the mass. A grain of dust will follow exactly the same orbital path as, say, Jupiter. It's the redshift/blueshift of the actual star that you need to measure.
  • bioweek 17y ago
    Oh so when the planet is between us and its star, it pulls the star towards us which blueshifts the light? That sounds hard to detect.
    • fh 17y ago
      > That sounds hard to detect. Well, obviously you need really precise spectrometers, but just because the effect is tiny, doesn't mean that you can't detect it.