| One contribution to astronomy by the HK Project in determining
the rotation periods for slowly-rotating stars. The rotation of rapidly-rotating
stars can be estimated from the Doppler broadening of the lines in their
spectra. However, this broadening is much too narrow to permit accurate
determinations of rotation for more slowly-rotating stars like the Sun.
stars. The program to measure and monitor rotation began in 1980 when the
HK Project gained almost exclusive use of the 60-inch telescope, and has
continued to the present. The rotation periods of over 100 dwarf and giants
stars have been measured. |
 HD 82885 (G8IV-V) 18 days |
 HD 149661 (K0V) 20 days |
 HD 4628 (K4V) 39 days |
 HD 166208 (G8II) 80 days |
Sample rotation curves for a few dwarf and giant stars.
