R CrB: Long‐period variations of radial velocity and velocity of outflow

The recently discovered variation in the mean radial velocity (RV) of R CrB on a time scale of about 10,000 days may be associated with a long‐term pulsation of a star with the amplitude of about 2.5 km s −1 , which results in the known mass loss of the star at the rate of 10 −6 times the mass of the Sun. It is also possible the connection with the 46‐year cycle in the sequence of the great R CrB declines. The absence of an obvious connection between the onset of R CrB decline and a certain phase of the 40‐day pulsation is suggested to relate to a long time delay between the processes in the noncoherently pulsating photosphere and in the zone of dust condensation. The search for the long‐term variability of the RV of R CrB from the data of the recently published large homogeneous database made it possible to identify two types of unique behavior of the RV in the JD 2451500–2454400 interval immediately before the unique Great decline in 2007. At first, the RV showed a superposition of known 40‐day pulsations of six pulsations with a period of 238 days, an average velocity of 25 km s −1 and amplitude of 3 km s −1 . Near JD 2454600, this pulsation was abruptly replaced by the 792‐day cycle. The cycle has a radically different half, with an average velocity about of 24.5 km s −1 . The first half can be termed abnormal because of the unique central 40‐day pulsation with a very high amplitude of about 14 km s −1 . The second half of cycle is a superposition of the half‐wave normal‐like prolonged pulsation and pulsations with a period of about 42 days and an amplitude of about 3 km s −1 . At the beginning of the third cycle, the IV Great RCB‐type decline started.