Asteroids with Satellites Database--Johnston's Archive

(5121) Numazawa

compiled by Wm. Robert Johnston
last updated 30 April 2022

--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: 2.230617386 AU
orbital period P: 3.331546096 yr
(= 1216.8472114 d)
eccentricity e: 0.170445538
perihelion distance q: 1.850418607 AU
aphelion distance Q: 2.6108161655 AU
inclination i: 6.4549291°
argument of perihelion ω: 20.8590152°
ascending node Ω: 358.2533503°
mean anomaly M: 49.7788199°
perihelion passage TP: 2021 Aug 05.741061
Epoch: 2022 Jan 21
data arc: 1941-2022 (2828 obs.)
Earth MOID: 0.85404 AU
Jupiter Tisserand invariant TJ: 3.615


orbital data, secondary:
semimajor axis as: 12 km [*E]
separation/primary radius as/rp:3.4 [*E]
separation/Hill radius as/rH:0.010 [*E]
orbital period Ps: 0.7158 ± 0.0004 d [B22a]
eccentricity es: ?
normalized ang. mom. αL: ?

other data, system (combined):
absolute mag. H: 13.11 [MPC]
slope parameter G: (0.15) [*A]
effective diameter dE: 7.24 ± 0.13 km [M12b]
geometric albedo: 0.256 ± 0.029 [M12b]
color index U-B: ?
color index B-V: ?
taxonomic type: ?
mass m: ?
density ρ: (1.6 g/cm3) [*A]
Hill radius rH: 1200 km [*E]

other data, primary:
diameter dp: 7.01 ± 0.13 km [*D]
rotation period RPp: 2.6646 ± 0.0002 h [B22a]
amplitude in mag., rotational ΔM: 0.13 [B22a]
amplitude in mag., mutual events ΔM:0.105 ±0.035 [B22a]
pole direction Β, λ: ? , ?


other data, secondary:
diameter ds: >1.82 km [*D]
diameter ratio ds/dp: >0.26 [B22a]
component mag. difference ΔM: <2.9 [*D]
rotation period RPs: ?

-- (5121) Numazawa --discovery and notes:

Primary discovered 1989 Jan 15 from Kitami, Hokkaido, Japan by Yanai, Watanabe. Alternate designation(s): 1989 AX1, 1941 WO, 1954 PA, 1984 QF1. Linked to prediscovery observations from 1941 Nov 16.

Companion discovered 2021 Oct 20 by V. Benishek, P. Pravec, R. Durkee using lightcurve observations from Sopot Observatory, Serbia; Chuguev station, Kharkiv Observatory, Ukraine; Shed of Science South Observatory, Pontotoc, Texas, USA. Announced 2022 Feb 14 [B22a].

--Links, more technical:

--Links, less technical:

--Links to ADS abstracts:


© 2022 by Wm. Robert Johnston.
Last modified 30 April 2022.
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