283 Emma

283 Emma is a large asteroid of the asteroid belt and the namesake of the Emma family. It was discovered by Auguste Charlois on 8 February 1889, in Nice, France. The reason for its name is unknown.[5]

283 Emma
A three-dimensional model of 283 Emma based on its light curve
Discovery
Discovered byAuguste Charlois
Discovery date8 February 1889
Designations
(283) Emma
Pronunciation/ˈɛmə/[1]
Main belt (Emma)
Orbital characteristics[2]
Epoch 31 July 2016 (JD 2457600.5)
Uncertainty parameter 0
Observation arc122.26 yr (44655 d)
Aphelion3.49701 AU (523.145 Gm)
Perihelion2.59675 AU (388.468 Gm)
3.04688 AU (455.807 Gm)
Eccentricity0.14773
5.32 yr (1942.6 d)
17.07 km/s
127.107°
0° 11m 7.148s / day
Inclination7.99162°
304.369°
53.7020°
Known satellites1 (9±5 km)[3]
Physical characteristics
Dimensions148.06±4.6 km (IRAS)[2]
160±10 km (AO)[3]
Mass1.38×1018 kg[4]
Mean density
0.81±0.08 g/cm³[4]
6.896 h (0.2873 d)[2]
0.0262±0.002[2] (Dark)
8.72[2]

    Measurements made with the IRAS observatory give a diameter of 145.70 ± 5.89 km and a geometric albedo of 0.03 ± 0.01. By comparison, the MIPS photometer on the Spitzer Space Telescope gives a diameter of 145.44 ± 7.72 km and a geometric albedo of 0.03 ± 0.01. When the asteroid was observed occulting a star, the results showed a diameter of 148.00 ± 16.26 km.[6]

    Satellite

    A companion for 283 Emma was detected on 14 July 2003 by W. J. Merline et al. using the Keck II telescope and is designated S/2003 (283) 1. The announcement is contained in the International Astronomical Union Circular (IAUC) 8165.[7] The satellite orbits at a semi-major axis of about 581 km with an eccentricity of 0.12.[3] Emma has a hill sphere with a radius of about 28,000 km.[3]

    References
    1. "Emma". Dictionary.com Unabridged. Random House.
    2. "JPL Small-Body Database Browser: 283 Emma". Solar System Dynamics (2008-10-30 last obs). Retrieved 11 May 2016.
    3. Marchis, Franck; P. Descamps; J. Berthier; D. hestroffer; F. vachier; M. Baek; A. Harris; D. Nesvorny (2008). "Main Belt Binary Asteroidal Systems With Eccentric Mutual Orbits". Icarus. 195 (1): 295–316. arXiv:0804.1385. Bibcode:2008Icar..195..295M. doi:10.1016/j.icarus.2007.12.010.
    4. Jim Baer (12 December 2010). "Recent Asteroid Mass Determinations". Personal Website. Archived from the original on 29 January 2009. Retrieved 17 July 2015.
    5. Lutz D. Schmadel (2003). Dictionary of Minor Planet Names (5th ed.). Springer Science & Business Media. p. 40. ISBN 978-3-540-00238-3.
    6. Ryan, Erin Lee; et al. (April 2012), "The Kilometer-Sized Main Belt Asteroid Population as Revealed by Spitzer", arXiv:1204.1116 [astro-ph.EP].
    7. S/2003 (283) 1 (Circular No. 8165)

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