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
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)
