Asteroids with Satellites Database--Johnston's Archive

(3169) Ostro

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, Hungaria


orbital data, primary (osculating elements) [JPL] :
semimajor axis a: 1.891834941 AU
orbital period P: 2.602154423 yr
(= 950.4369029 d)
eccentricity e: 0.066894323
perihelion distance q: 1.76528192 AU
aphelion distance Q: 2.018387960 AU
inclination i: 24.9057190°
argument of perihelion ω: 32.448672°
ascending node Ω: 96.398591°
mean anomaly M: 26.055218°
perihelion passage TP: 2014 Mar 15.2115
Epoch: 2014 May 23
data arc: 1953-2014 (744 obs.)
Earth MOID: 0.795439 AU
Jupiter Tisserand invariant TJ: 3.842


orbital data, secondary:
binary dynamical type:B [M09a]
semimajor axis as: 5.2 km [D07b]
separation/primary radius as/rp:2.7 [*D]
separation/Hill radius as/rH:0.0063 [*D]
orbital period Ps: 0.2712 ± 0.00004 d [D07b]
eccentricity es: ?
normalized ang. mom. αL: 9.23 [M09a]

other data, system (combined):
absolute mag. H: 12.73 [MPC]
slope parameter G: (0.15) [*A]
effective diameter dE: 5.15 ± 0.08 km [M11b]
geometric albedo: 0.423 ± 0.067 [M11b]
color index U-B: 0.306 [JPL]
color index B-V: 0.771 [JPL]
taxonomic type: Xe (SMASSII) [JPL]
TS (Tholen) [JPL]
mass m: 1.86x1014 ± 6.2x1013 kg [C12a]
density ρ: 2.6 ± 0.2 g/cm3[D07b]
Hill radius rH: 830 km [*D]

other data, primary:
diameter dp: 3.89 ± 0.06 km [*D]
dimensions :4.4 x 3.4 x 3.2km [D07b]
rotation period RPp: 6.509 ± 0.001 h [D07b]
amplitude in mag., rotational ΔM: 0.35 [D05c]
amplitude in mag., mutual events ΔM:0.75 [D05c]
pole direction Β, λ: ? , ?


other data, secondary:
diameter ds: 3.38 ± 0.07 km [*D]
dimensions :4.8 x 2.6 x 2.4km [D07b]
diameter ratio ds/dp: 0.87 ± 0.01 [D07b]
component mag. difference ΔM: 0.30 ± 0.02 [*D]
rotation period RPs: ?

-- (3169) Ostro --discovery and notes:

Primary discovered 1981 Jun 04 from Anderson Mesa Station, Arizona, USA by E. Bowell. Alternate designation(s): 1981 LA . Linked to prediscovery observations from 1953 Dec 31. Permanent number assigned 1985 Jan 07.

Named 1987 Apr 14 for Steven J. Ostro (1946-2008) [MPC11749].

Companion discovered 2005 Nov 05 by P. Descamps, F. Marchis, A. Peyrot, J.-P. Teng-Chuen-Yu, J. Dorseuil, B. Payet, T. Dijoux, Y. Leonie, H. Berrouachdi, C. Chion Hock, F. Bernard, C. Benard, J. Berthier, D. Hestroffer, and F. Vachier using lightcurve observations from Institut de Mecanique Celeste et de Calcul des Ephemerides; Makes Observatory, Reunion. Announced 2005 Dec 20 [D05c].

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--Links to ADS abstracts:


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