Asteroids with Satellites Database--Johnston's Archive

(4288) Tokyotech

compiled by Wm. Robert Johnston
last updated 18 December 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: main belt asteroid


orbital data, primary (osculating elements) [JPL] :
semimajor axis a: 2.628454679 AU
orbital period P: 4.261384675 yr
(= 1556.500149 d)
eccentricity e: 0.176082315
perihelion distance q: 2.1656303 AU
aphelion distance Q: 3.091279063 AU
inclination i: 14.025503°
argument of perihelion ω: 325.381242°
ascending node Ω: 44.586688°
mean anomaly M: 341.053994°
perihelion passage TP: 2019 Jul 17.915170
Epoch: 2019 Apr 27
data arc: 1959-2019 (2017 obs.)
Earth MOID: 1.181 AU
Jupiter Tisserand invariant TJ: 3.337


orbital data, secondary:
semimajor axis as: 30 km [*E]
separation/primary radius as/rp:5.1 [*E]
separation/Hill radius as/rH:0.015 [*E]
orbital period Ps: 1.2615 d [A19a]
eccentricity es: ?
normalized ang. mom. αL: ?

other data, system (combined):
absolute mag. H: 11.6 [MPC]
slope parameter G: (0.15) [*A]
effective diameter dE: 12.3 ± 0.09 km [M**]
geometric albedo: 0.223 ± 0.022 [M**]
color index U-B: ?
color index B-V: ?
taxonomic type: ?
mass m: ?
density ρ: (1.6 g/cm3) [*A]
Hill radius rH: 2000 km [*E]

other data, primary:
diameter dp: 11.78 ± 0.09 km [*D]
rotation period RPp: 3.18 ± 0.0002 h [A19a]
amplitude in mag., rotational ΔM: 0.18 [A19a]
amplitude in mag., mutual events ΔM:0.15 [A19a]
pole direction Β, λ: ? , ?


other data, secondary:
diameter ds: >3.53 km [*D]
diameter ratio ds/dp: >0.30 [A19a]
component mag. difference ΔM: <2.6 [*D]
rotation period RPs: 30.26 ± 0.01 h [A19a]

-- (4288) Tokyotech --discovery and notes:

Primary discovered 1989 Oct 08 from Chiyoda by T. Kojima. Alternate designation(s): 1989 TQ1, 1951 XD1, 1959 SJ, 1962 JG, 1980 NU, 1983 EQ3, 1983 HA2, A921 XA. Linked to prediscovery observations from 1951. Permanent number assigned 1989 Dec 12.

Named 2008 Aug 19 for the Tokyo Institute of Technology [MPC063639].

Companion discovered 2019 Oct 31 by D. Augustin, R. Behrend, M. Deldem, D. Starkey, J. M. Bosch, F. Soldan, J. Delgado, R. G. Farfan, and R. Montaigut using lightcurve observations from Fregenal de la Sierra, Spain; Pichasca, Chile; Geneva Observatory; Les Barres Observatory, Lamanon, France; DeKalb Observatory, Auburn, Indiana, USA; Amanecer Arrakis Observatory, Seville, Spain; Nuevos Horizontes Observatory, Seville, Spain; Uraniborg Observatory, Sevilla, Spain; OPERA Observatory, Saint Palais, France. Announced 2019 Dec 17 [A19a].

--Links, more technical:

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--Links to ADS abstracts:


© 2019 by Wm. Robert Johnston.
Last modified 18 December 2019.
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