I've been watching the TESS mission closely as I did the successful Kepler mission.

Before TESS launched, I remember reading several articles and published papers that modeled the expected number planet candidates TESS was to find (and the size distribution).

The numbers were in the 10,000 to 20,000 range with dozens of Earth sized planets and many hundreds less than 2x the diameter of earth. Here is one example from NASA:


"Astronomers predict that TESS will discover dozens of Earth-sized planets and up to 500 planets less than twice the size of Earth. In addition to Earth-sized planets, TESS is expected to find some 20,000 exoplanets in its two-year prime mission. TESS will find upwards of 17,000 planets larger than Neptune."

However, TESS has completed it's full 2-year initial run and, although the data is still be processed with more candidates to be picked from the data, the tally is much lower at 2,174 as of Sept 1, 2020. This is only about 11% of the expected number.

What am I missing? Three possibilities:

1) The bulk of the data analysis not begun or perhaps they have significantly delayed the release of the results. (Even the first year's data, downloaded over a year ago, should have produced close to 10,000 planets)
2) The expectation of 20,000 exoplanets is from possible extended missions with many more years of orbits?
3) Or, as I fear, they just didn't find as many as expected in this initial 2 year run. (But I don't see any discussions of the reasons: Technical issues, solar atmospheres too noisy, or simply fewer planets than originally expected out there?)

Any insights from TESS followers?


Steven Miller