Asteroids with Satellites Database--Johnston's Archive
(3959)
Irwin
compiled by Wm. Robert Johnston
last updated
19 February 2023
--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
orbital data, primary (osculating elements)
[JPL]
: |
semimajor axis a: |
2.2586517612 AU
| |
orbital period P: |
3.3945492741 yr
(= 1239.8591224 d)
| |
eccentricity e: |
0.187459657
| |
perihelion distance q: |
1.835245677 AU
| |
aphelion distance Q: |
2.6820578452 AU
| |
inclination i: |
3.28523173°
| |
argument of perihelion ω: |
198.1795707°
| |
ascending node Ω: |
210.793769°
| |
mean anomaly M: |
37.438363°
| |
perihelion passage TP: |
2022 Oct 19.060289
| |
Epoch: |
2023 Feb 25
| |
data arc: |
1954-2023
(3045 obs.)
| |
Earth MOID: |
0.844144 AU
| |
Jupiter Tisserand invariant TJ: |
3.596
|
orbital data, secondary:
|
semimajor axis as: |
6.6
km
[*E]
| |
separation/primary radius as/rp: | 3.3 [*E] | |
separation/Hill radius as/rH: | 0.012 [*E] | |
orbital period Ps: |
0.6517
± 0.0002
d [B23d]
| |
eccentricity es: |
?
| |
normalized ang. mom. αL: |
?
|
|
other data, system (combined):
|
absolute mag. H: |
14.08
[MPC]
| |
slope parameter G: |
(0.15) [*A]
| |
effective diameter dE: |
4.14
± 0.33
km [M**]
| |
geometric albedo: |
0.259
± 0.089
[M**]
| |
color index U-B: |
?
| |
color index B-V: |
?
| |
taxonomic type: |
?
| |
mass m: |
?
| |
density ρ: |
(1.6
g/cm3) [*A]
| |
Hill radius rH: |
570 km [*E]
|
other data, primary:
|
diameter dp: |
3.98
± 0.32
km [*D]
| |
rotation period RPp: |
3.2591
± 0.0003
h [B23d]
| |
amplitude in mag., rotational ΔM: |
0.11
[B23d]
| |
amplitude in mag., mutual events ΔM: | 0.135 ±0.045 [B23d] | |
pole direction Β, λ: |
?
,
?
|
other data, secondary:
|
diameter ds: |
>1.15
km [*D]
| |
diameter ratio ds/dp: |
>0.29
[B23d]
| |
component mag. difference ΔM: |
<2.7
[*D]
| |
rotation period RPs: |
?
| |
|
|
--
(3959) Irwin
--discovery and notes:
Primary discovered
1954 Oct 28
from
Brooklyn, Indiana, USA
by
Goethe Link Observatory.
Alternate designation(s):
1954 UN2,
1981 TP4, 1981 UX10, 1986 CY1.
Permanent number assigned 1989 Feb 20.
Named 1995 Sep 09 for John B. Irwin (1909-1997) [MPC025652].
Companion discovered
2022 Nov 14
by V. Benishek, F. Salvaggio, R. Papini, A. Marchini, P. Pravec, F. Pilcher, and R. Durkee
using
lightcurve
observations from Sopot Observatory, Serbia; Wild Boar Remote Observatory, Florence, Italy; Astronomical Observatory of the University of Siena; Organ Mesa Observatory, Las Cruces, New Mexico, USA; Shed of Science South Observatory, Pontotoc, Texas, USA.
Announced
2023 Feb 09 [B23d].
--Links, more technical:
--Links, less technical:
--Links to ADS abstracts:
©
2023
by Wm. Robert Johnston.
Last modified
19 February 2023.
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