palRvlsrd palRvlsrd - Velocity component in a given direction due to the Sun's motion with respect to the dynamical Local Standard of Rest

Description:

This function returns the velocity component in a given direction due to the Sun's motion with respect to the dynamical Local Standard of Rest. The result is $+$ve when the Sun is receding from the given point on the sky.

Invocation:

double palRvlsrd( double r2000, double d2000 )

Arguments:

r2000 = double (Given)

J2000.0 mean RA (radians)

d2000 = double (Given)

J2000.0 mean Dec (radians)

Returned Value:

Component of "peculiar" solar motion in direction R2000,D2000 (km/s).

Notes:

• The Local Standard of Rest used here is the "dynamical" LSR, a point in the vicinity of the Sun which is in a circular orbit around the Galactic centre. The Sun's motion with respect to the dynamical LSR is called the "peculiar" solar motion.

• There is another type of LSR, called a "kinematical" LSR. A kinematical LSR is the mean standard of rest of specified star catalogues or stellar populations, and several slightly different kinematical LSRs are in use. The Sun's motion with respect to an agreed kinematical LSR is known as the "standard" solar motion. To obtain a radial velocity correction with respect to an adopted kinematical LSR use the routine sla_RVLSRK.

Reference

• Delhaye (1965), in "Stars and Stellar Systems", vol 5, p73.