Bardwell is a member of the Themis family, a dynamical family of outer-belt asteroids with nearly coplanar ecliptical orbits. It orbits the Sun at a distance of 2.6–3.7 AU once every 5 years and 6 months (2,020 days). Its orbit has an eccentricity of 0.18 and an inclination of 2° with respect to the ecliptic.[1]
Its orbit has an eccentricity of 0.18 and an inclination of 2° with respect to the ecliptic.[1] It was first identified as 1926 TO at Simeiz Observatory in 1926, extending the body's observation arc by 24 years prior to its official discovery observation.[11]
In the Tholen taxonomy, Bardwell is a blueish B-type asteroid, a rare subtype of the abundant carbonaceous C-types found in the outer belt. The spectra of B-type bodies show a broad absorption feature at one micron wavelength that is associated with the presence of magnetite and is what gives the asteroid its blue tint.[13] There are only a few dozens asteroids of this type known to exist.[14]
Rotation period
In the late 1970s, a rotational lightcurve of Bardwell was obtained by American astronomer Edward Tedesco. It gave a provisional rotation period of 18 hours with a change in brightness of 0.2 magnitude (U=1).[a] As of 2017, no other photometric analysis of Bardwell has been made.
Diameter and albedo
According to the surveys carried out by the Infrared Astronomical Satellite IRAS and NASA's Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, Bardwell measures between 21.92 and 31.58 kilometers in diameter, and its surface has an albedo between 0.049 and 0.09.[4][6][7][8][10] The Collaborative Asteroid Lightcurve Link agrees with the results obtained by IRAS, that is, an albedo of 0.0642 and a diameter of 27.78 kilometers based on an absolute magnitude of 11.38.[3]
Notes
^ abTedesco, E.F. (1979) PhD Dissertation, New. Mex. State Univ. 280pp.; Rotation period of 18 hours with a brightness amplitude of 0.2. Summary figures at Asteroid Lightcurve Database for (1615) Bardwell