48 Doris

48 Doris is one of the largest main belt asteroids. It was discovered on 19 September 1857 by Hermann Goldschmidt from his balcony in Paris.

48 Doris

Discovery
Discovered by	Hermann Mayer Salomon Goldschmidt
Discovery date	19 September 1857
Designations
MPC designation	(48) Doris
Pronunciation	/ˈdɔːrɪs/[1]
Named after	Doris
Minor planet category	Main belt
Adjectives	Dorian /ˈdɔːriən/[2]
Orbital characteristics[3]
Epoch 31 December 2006 (JD 2454100.5)
Aphelion	500.093 Gm (3.343 AU)
Perihelion	430.463 Gm (2.877 AU)
Semi-major axis	465.278 Gm (3.110 AU)
Eccentricity	0.075
Orbital period (sidereal)	2003.453 d (5.49 a)
Mean anomaly	336.191°
Inclination	6.554°
Longitude of ascending node	183.754°
Argument of perihelion	257.583°
Physical characteristics
Dimensions	278 km × 142 km[4]
Mean diameter	215±3 km[5] 221.8±7.5 km (IRAS)[3]
Flattening	0.28[a]
Mass	(6.9±2.9)×1018 kg[5] (12.3±6.0)×1018 kg[b][6]
Mean density	1.32±0.55 g/cm3[5] 2.12±1.07 g/cm3[6]
Synodic rotation period	11.89 h[3]
Geometric albedo	0.066[5] 0.062[7]
Spectral type	C[3]
Absolute magnitude (H)	7.14[3]

To find a name for the object, Jacques Babinet of the Academy of Sciences created a shortlist and asked the geologist Élie de Beaumont to make the selection. De Beaumont chose Doris, after an Oceanid in Greek mythology. Since Doris was discovered on the same night as 49 Pales, de Beaumont suggested naming the two "The Twins".^[8]

Physical characteristics

An occultation on 19 March 1981 suggested a diameter of 219±25 km.^[9] Observations of an occultation on 14 October 1999, using four well-placed chords, indicate an ellipsoid of 278×142 km and that 48 Doris is an extremely irregularly shaped object.^[4]

Doris will pass within 0.019 AU of Pallas in June 2132.^[10]

In popular culture

48 Doris is a location in the text-based science fiction game Federation 2.^{[citation needed]}

Notes

1. Flattening derived from the maximum aspect ratio (c/a): ${\displaystyle f=1-{\frac {c}{a}}}$, where (c/a) = 0.72±0.01.^[5]
2. (6.1 ± 3.0) × 10⁻¹² M_☉