Asteroids with Satellites Database--Johnston's Archive

(8026) Johnmckay

compiled by Wm. Robert Johnston
last updated 21 September 2014

--Orbital and physical data--

(See this page for definitions of quantities; source codes in brackets, see this link for full references; *A, *D, and *E indicate assumed, derived, and estimated values, respectively.)

dynamical type, primary: main belt asteroid, Hungaria


orbital data, primary (osculating elements) [JPL] :
semimajor axis a: 1.925339521 AU
orbital period P: 2.671586196 yr
(= 975.7968581 d)
eccentricity e: 0.07492829
perihelion distance q: 1.78107713 AU
aphelion distance Q: 2.069601917 AU
inclination i: 19.932288°
argument of perihelion ω: 145.807757°
ascending node Ω: 217.736260°
mean anomaly M: 98.495429°
perihelion passage TP: 2013 Aug 29.0235
Epoch: 2014 May 23
data arc: 1989-2014 (659 obs.)
Earth MOID: 0.7992 AU
Jupiter Tisserand invariant TJ: 3.843


orbital data, secondary:
semimajor axis as: ?
orbital period Ps: ?
eccentricity es: ?
normalized ang. mom. αL: ?

other data, system (combined):
absolute mag. H: 14.8 [MPC]
slope parameter G: (0.15) [*A]
effective diameter dE: 1.69 ± 0.24 km [M11b]
geometric albedo: 0.815 ± 0.196 [M11b]
color index U-B: ?
color index B-V: ?
taxonomic type: ?
mass m: ?
density ρ: (1.6 g/cm3) [*A]
Hill radius rH: 230 km [*E]

other data, primary:
diameter dp: 1.69 ± 0.24 km [M11b]
rotation period RPp: 372 ± 5 h [W11a]
amplitude in mag., rotational ΔM: 0.12 [W10e]
amplitude in mag., mutual events ΔM:0.40 [W10e]
pole direction Β, λ: ? , ?


other data, secondary:
diameter ds: ?
diameter ratio ds/dp: ?
component mag. difference ΔM: ?
rotation period RPs: 2.300 ± 0.001 h [W10e]

-- (8026) Johnmckay --discovery and notes:

Primary discovered 1991 May 08 from Palomar Observatory, California, USA by E. F. Helin. Alternate designation(s): 1991 JA1, 1989 UF2. Linked to prediscovery observations from 1989 Oct 27. Permanent number assigned 1997 Nov 14.

Named 2012 Mar 08 for John McKay (1922-1975) [MPC78269].

Companion discovered 2010 Jul 11 using lightcurve observations. Announced 2010 Aug 06.

--Links, more technical:

--Links, less technical:

--Links to ADS abstracts:


© 2010-2013, 2014 by Wm. Robert Johnston.
Last modified 21 September 2014.
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