[KodiakLabs]

The passing of exoplanets (planets outside or solar system) if front of the host star is not the only way to detect the planets. The most common method used to be the Radial Velocity method.

Essentially, planets and stars orbit a common center of mass (which often lies witching the star’s radius). This effect essentially wobbles the parent star. Because we know the constituents of the star and it’s spectrum, this wobble causes a period red and blue shift (the Doppler effect). From the magnitude of this effect you can describe a lot of the planet’s orbit, but not everything. For example: you can describe the minimum mass of the planet but not the actual mass.

I’m not sure if the have used the radial velocity method of this star, but assume they would have.

[kazagistar]

You can't see a doppler shift if the pole of the orbit is facing sol, right? So there are still systems with invisible planets.

[roywiggins]

You can measure the position of the star in the sky and use that to detect systems that are "face on" to us (with the axis pointing at us) but it's harder.

http://www.planetary.org/explore/space-topics/exoplanets/ast...

[martinpw]

Sounds like 'harder' is an understatement - according to that article no planets have been discovered with this technique, and it is unlikely to yield any discoveries any time soon. (Technique is to directly observe the star wobbling in space rather than measure doppler shifts.)

[KodiakLabs]

You are correct. A component of the velocity of the wobble has to be in the line of sight. If not, it would be an edge case.