Q:

Why is the baseline of solar neutrinos is reported as "only" 10^10 meters while distance Sun-Earth is 1.5e11 meters?

Solar neutrinos correspond to neutrinos produced by the sun, and travelling until Earth. The distance Earth-Sun is 150 millions km, which is 1.5e8 times 1e3 = 1.5e11 meters.
So why the "baseline" (=distance of flight) of the solar neutrinos be "only" of 10^10 meters, as stated in the Table of properties of atmospheric neutrinos in the famous (most cited book in particle physics) Particle Data Group review :
http://pdg.lbl.gov/2019/reviews/rpp2019-rev-neutrino-mixing.pdf

A:

Here is the explanation from the authors :
"Yes, the radius of the Sun-Earth orbit is an average of ~10^11 m.
The neutrinos are mostly produced within the core of the Sun
which is the order of 0.2 of the Sun radius with distributions
peaking at sligtly different distances for the different neutrino
producing reactions. The same with the energy, which is not 1 MeV but depending on the
detection process can range from below 0.1 MeV to the maximum of ~20 MeV.
The table is meant to illustrate the ranges of dm^2 which can be
acess with the different sources.
So we just wrote the characteristic order  of magnitude. "
So the key point is that the order of magnitude is shown (so there could be a factor 10 discrepency)

