[semaphoreP]

I guess you're right. I know there aren't any observed transits, but I also don't know what the current constraints from monitoring the star's brightness for transit is (the star is actually so bright that it becomes hard to monitor for planet transits).

However, we have a good prior on the inclination of these planets, because we know the inclination of the dust disk around the star (https://www.scientificamerican.com/article/tau-ceti-s-dust-b...), and it is likely the planets are at a similar inclination. Because the disk isn't edge on, the planets also likely aren't, and won't transit.

[swamp40]

Since they are watching the star wobble, they probably have exact inclinations.

[goodcanadian]

"Wobble" is perhaps a imprecise term. What is actually measured is the doppler shift of a spectral line in the star. In other words, you are measuring the velocity of the star in the radial direction (towards and away from the Earth). By measuring how the velocity changes over time, you can get a orbital period for the planet. By measuring the magnitude of the velocity change, you can get a lower bound on the mass of the planet. It is only a lower bound as depending on the orbital inclination, some of the movement will be in the perpendicular direction (back and forth on the sky). We are unable to measure this movement precisely enough to detect (in most cases).

[hinkley]

Seems like it would have to be. If you've worked out from the wobble what the mass and orbit are it would stand to reason you've either calculated or at least stated an assumption regarding the inclination.

[tadfisher]

You can put a lower bound on both, but inclination introduces an unknown upper bound.

[Zitrax]

But shouldn't they have _some_ upper bound ? I guess for example that it's unlikely they are larger than 100 Earth masses since they call them Earth-sized.

[semaphoreP]

Measuring the star wobble (i.e. doppler shift) doesn't give inclinations.