Solar Mass Loss due to Solar Wind, According to Ulysses, Solar Orbiter, and Parker Solar Probe Data

An estimate of the average annual mass loss rate of the Sun due to the solar wind was made based on data obtained by the Ulysses, Parker Solar Probe (PSP), and Solar Orbiter (SolO) spacecrafts. The data used cover the solar cycle 23 and the first half of solar cycle 25. When extrapolating these data to a sphere of a radius 1 AU, the assumption of a quasi-stationary, spherically symmetric, radially propagating solar wind is made. The dependences of the bulk velocity and density of the wind (protons and alpha particles) on the heliocentric distance and latitude were analyzed. As a result, the applicability of this model was concluded at distances r > 0.3 AU, beyond which the solar wind takes the character of a steady flow. In the case of SolO, the mass fraction of alpha particles is estimated based on PSP data obtained at approximately the same time and at the same latitudes and distances. The resulting estimate of the solar mass outflow rate due to wind has both theoretical and practical significance: it is necessary for refining the evolutionary change in the solar mass, for creating long-term ephemerides, and for constructing a dynamic model of the Solar System.