Monthly Archives: February 2017

66. A Poynting-Robertson-like drag at the Sun’s surface

Contributed by Jeff Kuhn. Posted on February 14, 2017

A new analysis using about 4 years of HMI 5-min solar p-mode limb oscillations as a rotation “tracer” finds a large velocity gradient at the top of the photosphere. It is suggested that the net effect of the photospheric angular momentum loss is similar to Poynting-Robertson “photon braking” on, for example, Sun-orbiting dust.