10502 Armaghobs

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10502 Armaghobs
Discovery [1]
Discovered by E. F. Helin
Discovery site Palomar Obs.
Discovery date 22 August 1987
MPC designation (10502) Armaghobs
Pronunciation /ɑːrˈmɑːəbz/ ar-MAH-əbs
Named after
Armagh Observatory
(in Northern Ireland)[2]
1987 QF6 · 1980 PJ2
1994 RJ29
Orbital characteristics[1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc 36.73 yr (13,416 days)
Aphelion 3.0439 AU
Perihelion 1.5745 AU
2.3092 AU
Eccentricity 0.3182
3.51 yr (1,282 days)
0° 16m 51.24s / day
Inclination 21.927°
Physical characteristics
Dimensions 2.61±0.59 km[4]
2.97 km (calculated)[3]
24.978±0.002 h[5]
0.20 (assumed)[3]
S[3] · Q[6]
15.0[1][3] · 15.18 · 15.44±0.08[6]

10502 Armaghobs (/ɑːrˈmɑːəbz/ ar-MAH-əbz), provisional designation 1987 QF6, is an eccentric, rare-type stony asteroid and Mars-crosser from the inner regions of the asteroid belt, approximately 2.6 kilometers in diameter. The asteroid was discovered on 22 August 1987, by American astronomer Eleanor Helin at the Palomar Observatory in California, United States.[7] It was named for the Armagh Observatory in Northern Ireland.[2]

Orbit and classification[edit]

Armaghobs orbits the Sun in the inner main-belt at a distance of 1.6–3.0 AU once every 3 years and 6 months (1,282 days). Its orbit has an eccentricity of 0.32 and an inclination of 22° with respect to the ecliptic.[1] It was first identified as 1980 PJ2 at ESO's La Silla Observatory in 1980, extending the body's observation arc by 7 years prior to its official discovery observation at Palomar.[7]

Physical characteristics[edit]

The Armaghobs has been characterized as a relatively rare Q-type asteroid by Pan-STARRS photometric survey.[6]


In February 2013, a rotational lightcurve of Armaghobs was obtained from photometric observations by Kevin Hills at the Riverland Dingo Observatory at Moorook, South Australia. Lightcurve analysis gave a rotation period of 24.978 hours with a brightness variation of 0.51 magnitude (U=2).[5]

Diameter and albedo[edit]

According to the survey carried out by the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, Armaghobs measures 2.61 kilometers in diameter and its surface has an albedo of 0.22.[4] The Collaborative Asteroid Lightcurve Link assumes a standard albedo for stony asteroids of 0.20, and calculates a diameter of 2.97 kilometers with an absolute magnitude of 15.0.[3]


This minor planet was named after the Armagh Observatory in Northern Ireland. The present-day astronomical research institute was founded by Archbishop Richard Robinson in 1790. The Estonian astronomer Ernst Öpik, after whom 2099 Öpik is named, had been a long-time member of the Observatory. It is also known for the invention of the cup-anemometer by Thomas Robinson, the New General Catalogue compiled by John Dreyer, and Lindsay's Armagh-Dunsink-Harvard telescope.[2] The official naming citation was published by the Minor Planet Center on 9 January 2001 (M.P.C. 41937).[8]


  1. ^ a b c d "JPL Small-Body Database Browser: 10502 Armaghobs (1987 QF6)" (2017-05-04 last obs.). Jet Propulsion Laboratory. Retrieved 23 June 2017.
  2. ^ a b c Schmadel, Lutz D. (2007). Dictionary of Minor Planet Names – (10502) Armaghobs. Springer Berlin Heidelberg. p. 736. ISBN 978-3-540-00238-3. Retrieved 28 April 2016.
  3. ^ a b c d e f "LCDB Data for (10502) Armaghobs". Asteroid Lightcurve Database (LCDB). Retrieved 28 April 2016.
  4. ^ a b c Nugent, C. R.; Mainzer, A.; Bauer, J.; Cutri, R. M.; Kramer, E. A.; Grav, T.; et al. (September 2016). "NEOWISE Reactivation Mission Year Two: Asteroid Diameters and Albedos". The Astronomical Journal. 152 (3): 12. arXiv:1606.08923. Bibcode:2016AJ....152...63N. doi:10.3847/0004-6256/152/3/63. Retrieved 23 June 2017.
  5. ^ a b Hills, Kevin (January 2014). "Asteroid Lightcurve Analysis at Riverland Dingo Observatory (RDO): 2013 Results". The Minor Planet Bulletin. 41 (1): 2–3. Bibcode:2014MPBu...41....2H. ISSN 1052-8091. Retrieved 28 April 2016.
  6. ^ a b c Veres, Peter; Jedicke, Robert; Fitzsimmons, Alan; Denneau, Larry; Granvik, Mikael; Bolin, Bryce; et al. (November 2015). "Absolute magnitudes and slope parameters for 250,000 asteroids observed by Pan-STARRS PS1 - Preliminary results". Icarus. 261: 34–47. arXiv:1506.00762. Bibcode:2015Icar..261...34V. doi:10.1016/j.icarus.2015.08.007. Retrieved 28 April 2016.
  7. ^ a b "10502 Armaghobs (1987 QF6)". Minor Planet Center. Retrieved 28 April 2016.
  8. ^ "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 28 April 2016.

External links[edit]