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37 Fides

37 Fides 37 Fides symbol.svg
37Fides (Lightcurve Inversion).png
A three-dimensional model of 37 Fides based on its light curve
Discovered byR. Luther
Discovery dateOctober 5, 1855
MPC designation(37) Fides
Named after
1925 WH
Main belt
Orbital characteristics[1]
Epoch December 31, 2006 (JD 2454100.5)
Aphelion464.908 Gm (3.108 AU)
Perihelion325.340 Gm (2.175 AU)
395.124 Gm (2.641 AU)
1,567.873 d (4.29 a)
18.18 km/s
Physical characteristics
Dimensions108.35 km ±1.9
Mass1.3×1018 kg
Mean density
2.0 g/cm³
0.0303 m/s²
0.0573 km/s
0.3055 d (7.334 h)[2]
Albedo0.183[3] ±0.007
Temperature~167 K
Spectral type

Fides (/ˈfdz/ FY-deez; minor planet designation: 37 Fides) is a large main-belt asteroid. It was discovered by German astronomer Karl Theodor Robert Luther on October 5, 1855,[4] and named after Fides, the Roman goddess of loyalty. Fides was the last of the main-belt asteroids to be assigned an iconic symbol.[5] 37 Fides is also a S-type asteroid in the Tholen classification system.[1]

Photometric observations of this asteroid at multiple observatories during 1981–82 gave an unusual light curve with three minima and maxima. The curve changed with varying phase angle of the asteroid relative to the viewer and the position of the Sun, indicating the changing influence of shadows cast by surface features. The composite light curve has a best fit period estimate of 7.33 hours.[6] Austrian astronomer Hans Josef Schober has suggested that the multiple minima and maxima during each period may be an indication of a binary nature.[7]


  1. ^ a b Yeomans, Donald K., "37 Fides", JPL Small-Body Database Browser, NASA Jet Propulsion Laboratory, retrieved 7 April 2013.
  2. ^ Asteroid Lightcurve Parameters, Planetary Science Institute, archived from the original on 14 June 2006, retrieved 3 November 2008
  3. ^ Asteroid Data Archive, Planetary Science Institute, archived from the original on 23 May 2006, retrieved 3 November 2008.
  4. ^ "Numbered Minor Planets 1–5000", Discovery Circumstances, IAU Minor Planet center, retrieved 7 April 2013.
  5. ^ Gould, B. A. (1852), "On the Symbolic Notation of the Asteroids", Astronomical Journal, 2: 80, Bibcode:1852AJ......2...80G, doi:10.1086/100212.
  6. ^ Zappla, V.; et al. (July 1983), "Remarkable modification of light curves for shadowing effects on irregular surfaces - The case of the asteroid 37 Fides", Astronomy and Astrophysics, 123 (2): 326–330, Bibcode:1983A&A...123..326Z.
  7. ^ Schober, H. J. (February 1984), "A comparison between binary star light curves and those of possible binary asteroids", Astrophysics and Space Science, 99 (1–2), pp. 387–392, Bibcode:1984Ap&SS..99..387S, doi:10.1007/BF00650261.

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