Asteroids with Satellites Database--Johnston's Archive

(539940) 2017 HW1

compiled by Wm. Robert Johnston
last updated 7 June 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: NEA, Amor

orbital data, primary (osculating elements) [JPL] :
semimajor axis a: 2.13745098 AU
orbital period P: 3.124958435 yr
(= 1141.412625 d)
eccentricity e: 0.4588695
perihelion distance q: 1.15663991 AU
aphelion distance Q: 3.11826205 AU
inclination i: 33.944796°
argument of perihelion ω: 168.892117°
ascending node Ω: 41.3439928°
mean anomaly M: 11.653678°
perihelion passage TP: 2020 Apr 24.05096
Epoch: 2020 May 31
data arc: 2012-2020 (495 obs.)
Earth MOID: 0.154952 AU
Jupiter Tisserand invariant TJ: 3.379

orbital data, secondary:
semimajor axis as: 20 km [*E]
separation/primary radius as/rp:45 [*E]
separation/Hill radius as/rH:0.25 [*E]
orbital period Ps: 1.092 ± 0.004 d [W20a]
eccentricity es: ?
normalized ang. mom. αL: ?

other data, system (combined):
absolute mag. H: 17.8 [MPC]
slope parameter G: (0.15) [*A]
effective diameter dE: 0.92 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: 80 km [*E]

other data, primary:
diameter dp: 0.88 km [*E]
rotation period RPp: 2.633 ± 0.001 h [W20a]
amplitude in mag., rotational ΔM: 0.12 [W20a]
amplitude in mag., mutual events ΔM:0.105 ±0.015 [W20a]
pole direction Β, λ: ? , ?

other data, secondary:
diameter ds: >0.27 km [*E]
diameter ratio ds/dp: >0.31 ± 0.03 [W20a]
component mag. difference ΔM: <2.5 [*D]
rotation period RPs: ?

-- (539940) 2017 HW1 --discovery and notes:

Primary discovered 2012 Oct 22 from Haleakala by Pan-STARRS 1. Permanent number assigned 2019 Aug 27.

Companion discovered 2020 Apr 22 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 May 06 [W20a].

--Links, more technical:

--Links, less technical:

--Links to ADS abstracts:

© 2020 by Wm. Robert Johnston.
Last modified 7 June 2020.
Return to Home. Return to Astronomy and Space. Return to Asteroids with Satellites.