Perpendicular (upper panel) and parallel (lower panel) one-hour-averaged (black dots) and five-hour-averaged (red dots) measurements of the temperatures vs. solar wind speed at 20, 30, 50, and 80 solar radii on Parker Solar Probe orbits 6, 7, 8, and 9. Linear least-squares fits to these data are illustrated as the black and red dashed curves whose equations are also given in the figure.