Open main menu

11573 Helmholtz, provisional designation 1993 SK3, is a Zhongguo asteroid from the outermost region of the asteroid belt, approximately 13 kilometers (8 miles) in diameter. It was discovered on 20 September 1993, by German astronomers Freimut Börngen and Lutz Schmadel at the Karl Schwarzschild Observatory in Tautenburg, Germany. It is one of few asteroids located in the 2 : 1 resonance with Jupiter. The asteroid was named for German physicist Hermann von Helmholtz.[2]

11573 Helmholtz
Discovery [1]
Discovered byF. Börngen
L. D. Schmadel
Discovery siteKarl Schwarzschild Obs.
Discovery date20 September 1993
MPC designation(11573) Helmholtz
Named after
Hermann von Helmholtz[2]
(German naturalist)
1993 SK3 · 1982 YN4
main-belt[2] · (outer)[1]
background[3] · Zhongguo[4]
Orbital characteristics[1]
Epoch 23 March 2018 (JD 2458200.5)
Uncertainty parameter 0
Observation arc34.92 yr (12,755 d)
Aphelion4.1213 AU
Perihelion2.3952 AU
3.2582 AU
5.88 yr (2,148 d)
0° 10m 3.36s / day
Physical characteristics
Mean diameter
13 km (est. at 0.057)[5]


Orbit and classificationEdit

Helmholtz is a non-family asteroid from the main belt's background population.[3] It is a member of the small group of Zhongguo asteroids, located in the Hecuba gap (2 : 1 mean motion resonance with Jupiter) near 3.27 AU. Contrary to the nearby unstable Griqua group, the orbits of the Zhongguos are stable over half a billion years.[4]

It orbits the Sun in the outer main-belt at a distance of 2.4–4.1 AU once every 5 years and 11 months (2,148 days; semi-major axis of 3.26 AU). Its orbit has an eccentricity of 0.26 and an inclination of 2° with respect to the ecliptic.[1] The asteroid was first observed as 1982 YN4 at Crimea–Nauchnij in December 1982. The body's observation arc begins at Palomar Observatory in January 1989.[2]

Physical characteristicsEdit

Diameter and albedoEdit

Based on a generic magnitude-to-diameter conversion, Helmholtz measures 13 kilometer in diameter for an absolute magnitude of 13.2 and an assumed albedo of 0.057, which is typical for carbonaceous asteroids. If the body was of stony rather than carbonaceous composition, its estimated diameter would be less than 7 kilometer.[5]

Rotation periodEdit

As of 2018, no rotational lightcurve of Helmholtz has been obtained from photometric observations. The body's rotation period, pole and shape remain unknown.[1][6]


This minor planet was named after German physiologist and physicist Hermann von Helmholtz (1821–1894), a prolific naturalists of the 19th century. The official naming citation was published by the Minor Planet Center on 20 March 2000 (M.P.C. 39658).[7] The lunar crater Helmholtz as well as the crater Helmholtz on Mars are also named in his honor.[8][9]


  1. ^ a b c d e f "JPL Small-Body Database Browser: 11573 Helmholtz (1993 SK3)" (2017-11-24 last obs.). Jet Propulsion Laboratory. Retrieved 27 April 2018.
  2. ^ a b c d "11573 Helmholtz (1993 SK3)". Minor Planet Center. Retrieved 2 February 2018.
  3. ^ a b "Small Bodies Data Ferret". Nesvorny HCM Asteroid Families V3.0. Retrieved 2 February 2018.
  4. ^ a b Roig, F.; Nesvorný, D.; Ferraz-Mello, S. (September 2002). "Asteroids in the 2 : 1 resonance with Jupiter: dynamics and size distribution [ Erratum: 2002MNRAS.336.1391R ]". Monthly Notices of the Royal Astronomical Society. 335 (2): 417–431. Bibcode:2002MNRAS.335..417R. doi:10.1046/j.1365-8711.2002.05635.x. Retrieved 2 February 2018.
  5. ^ a b "Asteroid Size Estimator". CNEOS NASA/JPL. Retrieved 2 February 2018.
  6. ^ "LCDB Data for (11573) Helmholtz". Asteroid Lightcurve Database (LCDB). Retrieved 2 February 2018.
  7. ^ "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 2 February 2018.
  8. ^ "Lunar crater Helmholtz". Gazetteer of Planetary Nomenclature. USGS Astrogeology Research Program.
  9. ^ "Martian crater Helmholtz". Gazetteer of Planetary Nomenclature. USGS Astrogeology Research Program.

External linksEdit