Asteroids with Satellites Database--Johnston's Archive

(66391) Moshup and Squannit

compiled by Wm. Robert Johnston
last updated 20 October 2019

--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: NEA, Aten (PHA)


orbital data, primary (osculating elements) [JPL] :
semimajor axis a: 0.642195596283 AU
orbital period P: 0.514636973926 yr
(= 187.97470486 d)
eccentricity e: 0.688720227
perihelion distance q: 0.199902499 AU
aphelion distance Q: 1.084488693357 AU
inclination i: 38.8825647°
argument of perihelion ω: 192.6184318°
ascending node Ω: 244.90961474°
mean anomaly M: 68.0861372°
perihelion passage TP: 2019 Mar 22.4486901
Epoch: 2019 Apr 27
data arc: 1998-2019 (3927 obs.)
Earth MOID: 0.0130854 AU
Jupiter Tisserand invariant TJ: 8.499


orbital data, secondary:
binary dynamical type:A [P07f]
semimajor axis as: 2.548 ± 0.015 km [O06a]
separation/primary radius as/rp:3.86940015186029 [*D]
separation/Hill radius as/rH:0.113999221679632 [*D]
orbital period Ps: 0.7259 ± 0.0015 d [O06a]
eccentricity es: 0.0004 ± 0.0019 [O06a]
inclination is:156.1° ± 2° [O06a]
ascending node Ωs:105.4° ± 3° [O06a]
argument of pericenter ωs:319.7° ± 182° [O06a]
pericenter passage TP:2001 May 26.41± 0.88 [O06a]
normalized ang. mom. αL: 1.06 [P07f]

other data, system (combined):
absolute mag. H: 16.5 [MPC]
16.38 [JPL]
slope parameter G: (0.15) [*A]
effective diameter dE: 1.39 ± 0.05 km [*D]
geometric albedo: 0.23 [*E]
color index U-B: ?
color index B-V: ?
taxonomic type: S: (SMASSII) [JPL]
mass m: 2.49x1012 ± 5.4x1010 kg [O06a]
density ρ: 1.97 ± 0.24 g/cm3[O06a]
Hill radius rH: 22 km [*D]

other data, primary:
diameter dp: 1.317 ± 0.04 km [O06a]
dimensions :1.532 x 1.495 x 1.347 km [O06a]
rotation period RPp: 2.7645 ± 0.0003 h [O06a]
amplitude in mag., rotational ΔM: 0.13 [H03a]
pole direction Β, λ: ? , ?
densityρp:1.97± 0.24/O06a g/cm3 [O06a]


other data, secondary:
diameter ds: 0.451 ± 0.027 km [O06a]
dimensions :0.571 x 0.463 x 0.349km [O06a]
axial ratios a/b, b/c:1.23;1.33 [*D]
diameter ratio ds/dp: 0.341 ± 0.025 [*D]
component mag. difference ΔM: 2.5 [*D]
rotation period RPs: 17.4 ± 0.1 h [O06a]
densityρs:2.81± 0.82/0.63 g/cm3 [O06a]

-- (66391) Moshup and Squannit --discovery and notes:

Primary discovered 1999 May 20 from Socorro, New Mexico, USA by LINEAR Program. Alternate designation(s): 1999 KW4, 1999 JL6. Linked to prediscovery observations from 1998 May 29. Permanent number assigned 2003 Sep 10.

Named 2019 Aug 27 for Eugene G. Fahnestock (1980-) [MPC115894].

Companion discovered 2001 May 21 using radar and lightcurve observations. Announced 2001 May 23. Permanent designation I Squannit, assigned 2019 Aug 27 [MPC115894].

--Links, more technical:

--Links, less technical:

--Links to ADS abstracts:


© 2001-2014, 2019 by Wm. Robert Johnston.
Last modified 20 October 2019.
Return to Home. Return to Astronomy and Space. Return to Asteroids with Satellites.