Asteroids with Satellites Database--Johnston's Archive

(23621) 1996 PA

compiled by Wm. Robert Johnston
last updated 8 October 2017

--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: 1.9042605551 AU
orbital period P: 2.627783354 yr
(= 959.8159974 d)
eccentricity e: 0.298768422
perihelion distance q: 1.33532763 AU
aphelion distance Q: 2.4731934763 AU
inclination i: 19.3435237°
argument of perihelion ω: 153.352392°
ascending node Ω: 143.775049°
mean anomaly M: 20.54288°
perihelion passage TP: 2017 Jul 11.229487
Epoch: 2017 Sep 04
data arc: 1983-2017 (720 obs.)
Earth MOID: 0.340597 AU
Jupiter Tisserand invariant TJ: 3.822

orbital data, secondary:
semimajor axis as: 5 km [*E]
separation/primary radius as/rp:4.2 [*E]
separation/Hill radius as/rH:0.020 [*E]
orbital period Ps: 0.8583 ± 0.0013 d [P17f]
eccentricity es: ?
normalized ang. mom. αL: ?

other data, system (combined):
absolute mag. H: 15.6 [MPC]
slope parameter G: (0.15) [*A]
effective diameter dE: 2.5 km [*E]
geometric albedo: (0.16 ) [*A]
color index U-B: ?
color index B-V: ?
taxonomic type: ?
mass m: ?
density ρ: (1.6 g/cm3) [*A]
Hill radius rH: 250 km [*E]

other data, primary:
diameter dp: 2.4 km [*E]
rotation period RPp: 2.6649 ± 0.0005 h [P17f]
amplitude in mag., rotational ΔM: 0.07 [P17f]
amplitude in mag., mutual events ΔM:0.08 ±0.04 [P17f]
pole direction Β, λ: ? , ?

other data, secondary:
diameter ds: 0.65 km [*E]
diameter ratio ds/dp: >0.27 [P17f]
component mag. difference ΔM: 2.8 [*D]
rotation period RPs: ?

-- (23621) 1996 PA --discovery and notes:

Primary discovered 1996 Aug 05 from Siding Spring Observatory, New South Wales, Australia by G. J. Garradd. Linked to prediscovery observations from 1983 Sep 14.

Companion discovered 2017 Jul 16 by D. Pray, J. Oey, P. Pravec, H. Kucakova, K. Hornoch, V. Benishek, A. Marchini, R. Papini, and F. Salvaggio using lightcurve observations from Sugarloaf Mountain Observatory, South Deerfield, MA; Ondrejov Observatory; Blue Mountain Observatory; Sopot Observatory, Serbia; Astronomical Observatory of the University of Siena. Announced 2017 Oct 04.

--Links, more technical:

--Links, less technical:

--Links to ADS abstracts:

© 2017 by Wm. Robert Johnston.
Last modified 8 October 2017.
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