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6312 Robheinlein, provisional designation 1990 RH4, is a bright Augusta or background asteroid from the inner regions of the asteroid belt, approximately 3.5 kilometers (2.2 miles) in diameter. It was discovered on 14 September 1990, by American astronomer Henry Holt at the Palomar Observatory in California. The L-type asteroid was named for American science fiction writer Robert A. Heinlein.[1]

6312 Robheinlein
Orbital diagram of Robheinlein
Discovery [1]
Discovered byH. E. Holt
Discovery sitePalomar Obs.
Discovery date14 September 1990
MPC designation(6312) Robheinlein
Named after
Robert A. Heinlein[1]
(science fiction writer)
1990 RH4 · 1982 BW2
main-belt[1][2] · (inner)
background[3] · Augusta[4][5]
Orbital characteristics[2]
Epoch 23 March 2018 (JD 2458200.5)
Uncertainty parameter 0
Observation arc36.26 yr (13,244 d)
Aphelion2.3358 AU
Perihelion2.0321 AU
2.1839 AU
3.23 yr (1,179 d)
0° 18m 19.44s / day
Physical characteristics
Mean diameter
3.588±0.657 km[6]


Orbit and classificationEdit

When applying the hierarchical clustering method to the asteroid's proper orbital elements, Robheinlein is considered to be a member of the Augusta family (Zappala)[5] as well as a non-family asteroid from the main belt's background population (Nesvorny).[3]

It orbits the Sun in the inner asteroid belt at a distance of 2.0–2.3 AU once every 3 years and 3 months (1,179 days; semi-major axis of 2.18 AU). Its orbit has an eccentricity of 0.07 and an inclination of 4° with respect to the ecliptic.[2] The body's observation arc begins with its first observation as 1982 BW2 at the Kleť Observatory in January 1982, more than 8 years prior to its official discovery observation at Palomar.[1]

Physical characteristicsEdit

Robheinlein is an L-type asteroid in the SDSS-based taxonomy. It has an absolute magnitude of 14.1.[1][2] As of 2018, no rotational lightcurve has been obtained from photometric observations. The body's rotation period, pole and shape remain unknown.[2]

Diameter and albedoEdit

According to the survey carried out by the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, Robheinlein measures 3.588 kilometers in diameter and its surface has a high albedo of 0.314.[6]


Based on a suggestion by Belgian amateur astronomer Jean Meeus, this minor planet was named after Robert Anson Heinlein (1907–1988), the Dean of Science Fiction, author of the mainstream literary classic Stranger in a Strange Land, and Science Fiction novels Starship Troopers and The Moon is a Harsh Mistress. [1] The official naming citation was published by the Minor Planet Center on 13 April 2006 (M.P.C. 56611).[8]

Heinlein helped narrate The Moon Landing with Walter Cronkite on CBS in 1969, was involved in the planning of the Star Wars Defense program in the 1980s, contributed the words Waldo and Grok to the English language, and popularized the phrases Space Marine, TANSTAAFL, and Pay it Forward.


  1. ^ a b c d e f g h "6312 Robheinlein (1990 RH4)". Minor Planet Center. Retrieved 25 May 2018.
  2. ^ a b c d e f "JPL Small-Body Database Browser: 6312 Robheinlein (1990 RH4)" (2018-04-26 last obs.). Jet Propulsion Laboratory. Retrieved 25 May 2018.
  3. ^ a b "Small Bodies Data Ferret". Nesvorny HCM Asteroid Families V3.0. Retrieved 6 December 2017.
  4. ^ "Asteroid 6312 Robheinlein". Small Bodies Data Ferret. Retrieved 25 May 2018.
  5. ^ a b V. Zappala (1995). "Asteroid Dynamical Families – EAR-A-5-DDR-FAMILY-V4.1". NASA Planetary Data System. Archived from the original on 3 October 2013. Retrieved 7 December 2017.
  6. ^ a b c Masiero, Joseph R.; Mainzer, A. K.; Grav, T.; Bauer, J. M.; Cutri, R. M.; Nugent, C.; et al. (November 2012). "Preliminary Analysis of WISE/NEOWISE 3-Band Cryogenic and Post-cryogenic Observations of Main Belt Asteroids" (PDF). The Astrophysical Journal Letters. 759 (1): 5. arXiv:1209.5794. Bibcode:2012ApJ...759L...8M. doi:10.1088/2041-8205/759/1/L8. Retrieved 25 May 2018.
  7. ^ Carvano, J. M.; Hasselmann, P. H.; Lazzaro, D.; Mothé-Diniz, T. (February 2010). "SDSS-based taxonomic classification and orbital distribution of main belt asteroids". Astronomy and Astrophysics. 510: 12. Bibcode:2010A&A...510A..43C. doi:10.1051/0004-6361/200913322. Archived from the original on 2 May 2018. Retrieved 25 May 2018.
  8. ^ "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 25 May 2018.

External linksEdit