(1656)
Asteroids with Satellites Database--Johnston's Archive
(1656) Suomi
compiled by Wm. Robert Johnston
last updated 11 October 2020
--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:_Mars crossing asteroid _orbital data, primary (osculating elements)_[JPL] :semimajor axis **a:**1.8778819257 AUorbital period **P:**2.5733711212 yr (= 939.915539 d)eccentricity **e:**0.123171623perihelion distance **q:**1.646580161 AUaphelion distance **Q:**2.1091836901 AUinclination **i:**25.0658521°argument of perihelion **ω:**287.499175°ascending node **Ω:**175.5387855°mean anomaly **M:**197.748597°perihelion passage **TP:2021 Jul 28.630099Epoch:2020 May 31data arc:1942-2020 (2393 obs.)Earth MOID:**0.754228 AUJupiter Tisserand invariant **TJ:**3.851 orbital data, secondary: semimajor axis **as:**30 km [*E]separation/primary radius **as/rp:**7.9 [*E]separation/Hill radius **as/rH:**0.031 [*E]orbital period **Ps:**2.413 ± 0.001 d [W20c]eccentricity es:?normalized ang. mom. αL:? | other data, system (combined): absolute mag. **H:**12.8 [MPC]slope parameter G: (0.15) [*A]effective diameter **dE:7.86 ± 0.7 km [JPL]geometric albedo:0.156 ± 0.032 [JPL]color index U-B:?color index B-V:?taxonomic type:**S (Tholen) [JPL]mass m:?density ρ: (1.6 g/cm3) [*A]Hill radius **rH:**980 km [*E] other data, primary: diameter **dp:**7.61 km [*D]rotation period **RPp:**2.5885 ± 0.0001 h [W20c]amplitude in mag., rotational **ΔM:**0.11 ± 0.01 [W20c]amplitude in mag., mutual events **ΔM:**0.07 ±0.01 [W20c]pole direction Β, λ:? , ? other data, secondary: diameter **ds:**>1.98 km [*D]diameter ratio **ds/dp:**>0.26 ± 0.02 [W20c]component mag. difference ΔM:<2.9 [*D]rotation period RPs:? |
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-- (1656) Suomi --discovery and notes:
Primary discovered 1942 Mar 11 from Turku, Finland by Y. Vaisala. Alternate designation(s): 1942 EC, 1955 HL. Linked to prediscovery observations from 1942 Mar 10. Permanent number assigned -.
Named 1976 Feb 20 [MPC003932].
Companion discovered 2020 Jun 09 by B. D. Warner, R. D. Stephens, and A. W. Harris using lightcurve observations from Center for Solar System Studies, Landers, California, USA. Announced 2020 Sep [W20c].
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--Links to ADS abstracts:
© 2020 by Wm. Robert Johnston.
Last modified 11 October 2020
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