4897 Tomhamilton

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4897 Tomhamilton
Discovery [1]
Discovered byE. F. Helin
Discovery sitePalomar Obs.
Discovery date22 August 1987
MPC designation(4897) Tomhamilton
Named after
Thomas Hamilton
(American writer)[2]
1987 QD6 · 1971 QV1
1971 SB1 · 1990 BN1
main-belt · (outer)
Orbital characteristics[1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc66.81 yr (24,402 days)
Aphelion3.4356 AU
Perihelion2.6792 AU
3.0574 AU
5.35 yr (1,953 days)
0° 11m 3.84s / day
Physical characteristics
Dimensions13.711±0.369 km[3]

4897 Tomhamilton, provisional designation 1987 QD6, is a stony asteroid from the outer region of the asteroid belt, approximately 14 kilometers in diameter. It was discovered on 22 August 1987, by American astronomer Eleanor Helin at Palomar Observatory, California. It was later named after American Thomas Hamilton, author of astronomy books and participant in the Apollo program.[2]

Classification and orbit[edit]

Tomhamilton orbits the Sun in the outer main-belt at a distance of 2.7–3.4 AU once every 5 years and 4 months (1,953 days). Its orbit has an eccentricity of 0.12 and an inclination of 11° with respect to the ecliptic.[1]

In August 1950, a first precovery was taken at Palomar, extending the asteroid's observation arc by 37 years prior to its official discovery observation.[2] It had also been previously identified as 1971 QV1 and 1971 SB1 at Crimea–Nauchnij.

On 11 January 2011, it was at opposition (coinciding with Hamilton's 72nd birthday) at a distance of 2.476 AU. Given the moderately elliptical orbit, this asteroid can on rare occasions reach an apparent magnitude from Earth of about 10.9.[citation needed]

Physical characteristics[edit]

Diameter and albedo[edit]

According to the survey carried out by NASA's Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, Tomhamilton measures 13.7 kilometers in diameter and its surface has an albedo of 0.215, which indicates that it of a stony rather than of a carbonaceous composition.[3]


As of 2017, no rotational lightcurve of Tomhamilton has been obtained from photometric observations. It rotation period, poles and shape remain unknown.[1][4]


This minor planet was named after Thomas William Hamilton, an American (born San Francisco, 1939) who was a child actor (he played "Barnaby" in Barnaby and Mr. O'Malley and was on the early television show Mr. I-Magination). As an adult he worked on the Apollo program, determining fuel requirements and radar accuracy requirements for lunar orbit rendezvous. He later worked as an astronomy educator and planetarium director, and is the author of time travel and science fiction novels, and also wrote five books on astronomical topics. Hamilton and Helin were acquainted, as he had interviewed her at an astronomical conference for a cable television show he was producing at the time. The approved naming citation was published by the Minor Planet Center on 4 October 2009 (M.P.C. 67215).[5]

Books by Hamilton[edit]

  • Books on astronomical topics:
    • Useful Star Names (ISBN 978-1-61204-614-3)
    • Our Neighbor Stars (978-1-61897-132-6)
    • Moons of the Solar System (978-1-62516-175-8)
    • Dwarf Planets and Asteroids (978-1-62857-728-0)
    • Impact Craters of Earth (978-1-63135-353-6)
  • Other books:

Hamilton has also had astronomical articles in The Constellation, and science fiction in Aphelion, Bewildering Stories, and Changingthetimes.[citation needed]


  1. ^ a b c d e "JPL Small-Body Database Browser: 4897 Tomhamilton (1987 QD6)" (2017-06-05 last obs.). Jet Propulsion Laboratory. Retrieved 4 August 2017.
  2. ^ a b c "4897 Tomhamilton (1987 QD6)". Minor Planet Center. Retrieved 26 August 2016.
  3. ^ a b c Masiero, Joseph R.; Mainzer, A. K.; Grav, T.; Bauer, J. M.; Cutri, R. M.; Dailey, J.; et al. (November 2011). "Main Belt Asteroids with WISE/NEOWISE. I. Preliminary Albedos and Diameters". The Astrophysical Journal. 741 (2): 20. arXiv:1109.4096. Bibcode:2011ApJ...741...68M. doi:10.1088/0004-637X/741/2/68. Retrieved 26 August 2016.
  4. ^ "LCDB Data for (4897) Tomhamilton". Asteroid Lightcurve Database (LCDB). Retrieved 4 August 2017.
  5. ^ "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 26 August 2016.

External links[edit]