Asteroids with Satellites Database--Johnston's Archive

(4951) Iwamoto

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

orbital data, primary (osculating elements) [JPL] :
semimajor axis a: 2.256428848 AU
orbital period P: 3.389539251 yr
(= 1238.029211 d)
eccentricity e: 0.166530009
perihelion distance q: 1.88066573 AU
aphelion distance Q: 2.632191963 AU
inclination i: 7.5280874°
argument of perihelion ω: 339.861910°
ascending node Ω: 101.089519°
mean anomaly M: 90.323691°
perihelion passage TP: 2013 Jul 16.37953
Epoch: 2014 May 23
data arc: 1931-2014 (1168 obs.)
Earth MOID: 0.897826 AU
Jupiter Tisserand invariant TJ: 3.593

orbital data, secondary:
binary dynamical type:B [M09a]
semimajor axis as: 31 km [*E]
separation/primary radius as/rp:14 [*E]
separation/Hill radius as/rH:0.043 [*E]
orbital period Ps: 4.917 ± 0.008 d [R07b]
eccentricity es: ?
normalized ang. mom. αL: 2.31 [M09a]

other data, system (combined):
absolute mag. H: 13.2 [MPC]
13.74 ± 0.06 [R07b]
slope parameter G: (0.15) [*A]
effective diameter dE: 5.52 ± 0.03 km [M11b]
geometric albedo: 0.186 ± 0.032 [M11b]
color index U-B: ?
color index B-V: ?
taxonomic type: S (SMASSII) [JPL]
mass m: ?
density ρ: (1.6 g/cm3) [*A]
Hill radius rH: 730 km [*E]

other data, primary:
diameter dp: 4.39 ± 0.02 km [*D]
rotation period RPp: 118.0 ± 0.2 h [R07b]
amplitude in mag., rotational ΔM: 0.34 [R07b]
pole direction Β, λ: ? , ?

other data, secondary:
diameter ds: 3.34 km [*D]
diameter ratio ds/dp: >0.76 [R07b]
component mag. difference ΔM: <0.60 [*D]
rotation period RPs: 118.0 ± 0.2 h [R07b]

-- (4951) Iwamoto --discovery and notes:

Primary discovered 1990 Jan 21 from Kani, Japan by Y. Mizuno and T. Furuta. Alternate designation(s): 1990 BM, 1931 UQ, 1985 QN6, 1985 RH5, 1989 WS3. Linked to prediscovery observations from 1931 Oct 17. Permanent number assigned 1991 Sep 23.

Named 1996 Mar 05 for Masayuki Iwamoto (1954-) [MPC26763].

Companion discovered 2007 May 11 by V. Reddy, R. Dyvig, P. Pravec, P. Kusnirak, A. Galad, L. Kornos, S. Gajdos, J. Vilagi, D. Pray, W. Cooney, J. Gross, D. Terrell, Yu. Krugly, J. Ries, K. Archer, J. Oey, M. Pikler, M. Husarik, R. Durkee, F. Colas, and A. Harris using lightcurve observations from University of North Dakota, Grand Forks; Badlands Observatory, Quinn, South Dakota, USA; Ondrejov Observatory, Czech Republic; Modra Observatory, Slovakia; Carbuncle Hill Observatory, Greene, Rhode Island, USA; Sonoita Research Observatory, Sonoita, Arizona, USA; Kharkiv Observatory, Ukraine; McDonald Observatory, Texas, USA; Ironwood Observatory, Oahu, Hawaii, USA; Leura, New South Wales, Australia; Skalnate Pleso Observatory; Shed of Science Observatory, Minneapolis, Minnesota, USA; Pic du Midi Observatory; Space Science Institute. Announced 2007 May 11 [R07b].

--Links, more technical:

--Links, less technical:

--Links to ADS abstracts:

© 2007-2008, 2014 by Wm. Robert Johnston.
Last modified 21 September 2014.
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