Asteroids with Satellites Database--Johnston's Archive

(31346) 1998 PB1

compiled by Wm. Robert Johnston
last updated 26 June 2021

--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: NEA, Amor


orbital data, primary (osculating elements) [JPL] :
semimajor axis a: 2.0294639991 AU
orbital period P: 2.8911593403 yr
(= 1056.0158932 d)
eccentricity e: 0.429985049
perihelion distance q: 1.15682482 AU
aphelion distance Q: 2.9021031761 AU
inclination i: 5.9637866°
argument of perihelion ω: 350.5342°
ascending node Ω: 299.732528°
mean anomaly M: 337.893737°
perihelion passage TP: 2021 Sep 03.846013
Epoch: 2021 Jul 01
data arc: 1998-2021 (615 obs.)
Earth MOID: 0.141241 AU
Jupiter Tisserand invariant TJ: 3.685


orbital data, secondary:
semimajor axis as: 4.6 km [*E]
separation/primary radius as/rp:7.8 [*E]
orbital period Ps: 2.308 ± 0.004 d [P21d]
eccentricity es: ?
normalized ang. mom. αL: ?

other data, system (combined):
absolute mag. H: 17.09 [MPC]
17.29 ± 0.08 [P21d]
slope parameter G: (0.15) [*A]
effective diameter dE: 1.26 km [*E]
geometric albedo: (0.16 ) [*A]
color index U-B: ?
color index B-V: ?
color index V-R:0.43 ± 0.02 [P21d]
taxonomic type: ?
mass m: ?
density ρ: (1.6 g/cm3) [*A]
Hill radius rH: 0 km [*E]

other data, primary:
diameter dp: 1.18 km [*E]
rotation period RPp: 2.7358 ± 0.0002 h [P21d]
amplitude in mag., rotational ΔM: 0.13 [P21d]
amplitude in mag., mutual events ΔM:0.15 [P21d]
pole direction Β, λ: ? , ?


other data, secondary:
diameter ds: >0.45 km [*D]
diameter ratio ds/dp: >0.38 [P21d]
component mag. difference ΔM: <2.1 [*D]
rotation period RPs: ?

-- (31346) 1998 PB1 --discovery and notes:

Primary discovered 1998 Aug 15 from Socorro, New Mexico, USA by Lincoln Laboratory Near-Earth Asteroid Research Team. Linked to prediscovery observations from 1998 Jul 14. Permanent number assigned 2001 Nov 30.

Companion discovered 2021 by Pravec, P., P. Kusnirak, K. Hornoch, P. Fatka, H. Kucakova, and C. Snodgrass using lightcurve observations. Announced 2021 Jun 16 [P21d].

--Links, more technical:

--Links, less technical:

--Links to ADS abstracts:


© 2021 by Wm. Robert Johnston.
Last modified 26 June 2021
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