|Ebbinghausen, E. G. Astronomy. 5th ed. Merrill, 1985.||"The sun's roational period is about 25 days at the equator,
27 days at 35 degrees latitude,
33 days at 75 degrees latitude, and about 35 days near the poles."
|Handbook of Chemistry and Physics. 61st ed. Florida: CRC Press, 1980.||"Physical data: (period of rotation sidereal days) sun 24.66225±.00003"||24.66225 days|
|Gutsch, William A. 1001 Things Everyone Should Know About the Universe. New York: Doubleday, 1998.||"At the equator, the sun turns around once in about 25 earth days."||25 days|
|Pananides, Nicholas A. Introductory Astronomy. Massachusetts: Addison Wesley, 1979.||"The rotation period at the equator is 25 days and increases to 27½ days at latitude 30 degrees. The period increses to 35 days at latitude 75 degrees."||25–35 days|
|Goth, George. The Magnitude of Physics. The Physics Teacher. December 1996.||"… period of rotation of sun: 2.125 × 106"||24.59 days|
The movement of solar surface features (sunspots) show that the sun is in rotation about its axis. Observations also reveal that the sun's equator is inclined about seven degrees to the plane of the ecliptic. The sun rotates from west to east in the same direction as the earth. However unlike the earth, the sun does not rotate as a solid body.
The motion of sunspots determine the rate of rotation at a particular latitude. Sunspots are fairly circular structures that contain two well-defined parts. The spots occur in pairs or in groups, however with two main spots. The line that joins the centers of a pair is almost parallel to the sun's equator. At the equator the sun's rotational period is twenty-five days while at higher latitudes the sun tends to rotate more slowly. The rotational period near the poles it is thirty-five days. In contrast to the earth, the position of a place on the sun changes as the places closer to the equator speed ahead. The surface of the sun is not solid but fluid.
Radhika Kapoor -- 1999