1615 Bardwell

1615 Bardwell

Discovery
Discovered by	Indiana Asteroid Program
Discovery site	Goethe Link Obs.
Discovery date	28 January 1950
Designations
MPC designation	1615 Bardwell
Named after	Conrad M. Bardwell (astronomer)
Alternative names	1950 BW · 1926 TO 1937 TJ · 1948 RB1 1948 RH1 · 1948 TG
Minor planet category	main-belt · Themis
Orbital characteristics
Epoch 31 July 2016 (JD 2457600.5)
Uncertainty parameter 0
Observation arc	89.55 yr (32708 days)
Aphelion	3.6822 AU (550.85 Gm)
Perihelion	2.5686 AU (384.26 Gm)
Semi-major axis	3.1254 AU (467.55 Gm)
Eccentricity	0.17816
Orbital period	5.53 yr (2018.1 d)
Mean anomaly	99.560°
Inclination	1.6890°
Longitude of ascending node	152.54°
Argument of perihelion	252.18°
Earth MOID	1.57686 AU (235.895 Gm)
Jupiter MOID	1.72107 AU (257.468 Gm)
Physical characteristics
Dimensions	27.78 km 31.579±0.250 km 25.01±1.49 km 31±3 km
Mean radius	13.89 ± 0.8 km
Rotation period	18 h (0.75 d)
Geometric albedo	0.0642 0.0497±0.0192 0.079±0.015 0.05±0.01 0.0642 ± 0.008
Spectral type	B–V = 0.692 U–B = 0.329 Tholen = B B
Absolute magnitude (H)	11.38

1615 Bardwell, provisional designation 1950 BW, is a rare-type bluish asteroid from the outer region of the asteroid belt, that measures about 30 kilometers in diameter. It was discovered by the Indiana Asteroid Program at the U.S. Goethe Link Observatory near Brooklyn, Indiana at on 28 January 1950.

The dark asteroid 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 five and a half years (2,014 days). Its orbit shows an eccentricity of 0.18 and is tilted by 2 degrees to the plane of the ecliptic. It has a rotation period of 18 hours and an albedo between 0.05 and 0.08, based on data from the IRAS, WISE and NEOWISE surveys.

It is a B-type asteroid under the Tholen classification taxonomy, 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 mircon wavelength that is associated with the presence of magnetite and is what gives the asteroid its blue tint. There are only a few dozens asteroids known to display such a B-spectrum.

The Themistian asteroids was named after Conrad M. Bardwell (1926–2010), a research associate at the Cincinnati Observatory and later associate director of the Minor Planet Center in Cambridge, Massachusetts, United States. Bardwell successfully established numerous identifications from observations in widely separated oppositions and provided observers with reliable data of orbital elements.

External links

• Asteroid Lightcurve Database (LCDB), query form (info)
• Dictionary of Minor Planet Names, Google books
• Asteroids and comets rotation curves, CdR – Observatoire de Genève, Raoul Behrend
• Discovery Circumstances: Numbered Minor Planets (1)-(5000) – Minor Planet Center
• 1615 Bardwell at the JPL Small-Body Database

• Discovery · Orbit diagram · Orbital elements · Physical parameters