1615 Bardwell
1615 Bardwell, with the provisional designation 1950 BW, is a rare-type Themistian asteroid located in the outer region of the asteroid belt, measuring approximately 27 kilometers in diameter. This celestial body was discovered on January 28, 1950, by the Indiana University’s Indiana Asteroid Program at the Goethe Link Observatory in Brooklyn, Indiana, USA. It was named in honor of the American astronomer Conrad Bardwell.
Orbit and Classification
Bardwell is classified as a member of the Themis family, a dynamical group of outer-belt asteroids characterized by nearly coplanar ecliptical orbits. The asteroid orbits the Sun at a distance of 2.6–3.7 AU, completing an orbit every 5 years and 6 months (or 2,020 days). Its orbital eccentricity measures 0.18, with an inclination of 2° relative to the ecliptic plane.
Initially identified as 1926 TO at the Simeiz Observatory in 1926, its observation arc was extended by 24 years before its official discovery.
Naming
This minor planet was named after Conrad M. Bardwell (1926–2010), who served as a research associate at the Cincinnati Observatory and later as the associate director of the Minor Planet Center in Cambridge, Massachusetts, USA. Bardwell played a vital role in successfully establishing numerous identifications based on observations from widely separated oppositions, providing the astronomical community with reliable data regarding orbital elements. The official naming citation was published by the Minor Planet Center on June 15, 1974 (M.P.C. 3643).
Physical Characteristics
According to the Tholen taxonomy, Bardwell is classified as a blueish B-type asteroid, a rare subtype among the more prevalent carbonaceous C-types found within the outer asteroid belt. The spectra from B-type bodies exhibit a broad absorption feature at a wavelength of one micron, associated with the presence of magnetite, which gives Bardwell its distinctive blue tint. Currently, only a few dozen known asteroids belong to this classification.
Rotation Period
In the late 1970s, American astronomer Edward Tedesco obtained a rotational lightcurve of Bardwell, revealing a provisional rotation period of 18 hours and a brightness variation of 0.2 magnitude (U=1). As of 2017, no further photometric analysis of Bardwell has been conducted.
Diameter and Albedo
Surveys conducted by the Infrared Astronomical Satellite (IRAS) and NASA’s Wide-field Infrared Survey Explorer, along with its subsequent NEOWISE mission, estimate Bardwell’s diameter to range between 21.92 and 31.58 kilometers, with a surface albedo ranging from 0.049 to 0.09. The Collaborative Asteroid Lightcurve Link concurs with the results from IRAS, noting an albedo of 0.0642 and a diameter of 27.78 kilometers based on an absolute magnitude of 11.38.