2839 Annette, provisional designation 1929 TP, is a stony Florian asteroid from the inner regions of the asteroid belt, approximately 5 kilometers in diameter. It was discovered on 5 October 1929, by American astronomer Clyde Tombaugh at Lowell Observatory during his search for Pluto. It was named after the discoverer's daughter.
The first rotational lightcurve of Annette was obtained by American astronomer Brian Warner at his Palmer Divide Observatory, Colorado, in December 2005. It gave a rotation period of 10.457 hours with a brightness variation of 0.92 magnitude (U=3-). In November 2006, a second lightcurve by astronomer Robert Buchheim at Altimira Observatory in southern California gave a concurring period of 10.4595 hours and an amplitude of 0.64 magnitude (U=3). He also noted a significantly fainter absolute magnitude of 14.35 than previously reported.
Diameter and albedo
According to the survey carried out by NASA's Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, Annette measures between 5.41 and 7.562 kilometers in diameter and its surface has an albedo between 0.056 and 0.47, while the Collaborative Asteroid Lightcurve Link assumes an albedo of 0.24 – derived from 8 Flora, the largest member and namesake of its family – and calculates a diameter of 3.66 kilometers using Robert Buchheim's fainter absolute magnitude of 14.35.