Asteroids with Satellites Database--Johnston's Archive
(59195)
1999 BG2
compiled by Wm. Robert Johnston
last updated
11 July 2026
--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: |
2.60945296858 AU
| |
orbital period P: |
4.21533809085 yr
(= 1539.65223768 d)
| |
eccentricity e: |
0.160748009
| |
perihelion distance q: |
2.1899885996 AU
| |
aphelion distance Q: |
3.02891733758 AU
| |
inclination i: |
26.306153258°
| |
argument of perihelion ω: |
296.51478859°
| |
ascending node Ω: |
176.17742829°
| |
mean anomaly M: |
171.78083739°
| |
perihelion passage TP: |
2024 Jun 04.32569255
| |
Epoch: |
2026 Jun 09
| |
data arc: |
1999-2025
(2200 obs.)
| |
Earth MOID: |
1.29632 AU
| |
Jupiter Tisserand invariant TJ: |
3.247
|
orbital data, secondary:
|
semimajor axis as: |
14.2
km
(separation)
[K26b]
| |
separation/primary radius as/rp: | 4.5 [*E] | |
separation/Hill radius as/rH: | 0.014 [*E] | |
orbital period Ps: |
1.1
d [*E]
| |
eccentricity es: |
?
| |
normalized ang. mom. αL: |
?
|
|
other data, system (combined):
|
absolute mag. H: |
14.93
[MPC]
| |
slope parameter G: |
(0.15) [*A]
| |
effective diameter dE: |
6.31
± 0.06
km [M19a]
| |
geometric albedo: |
0.044
± 0.013
[M19a]
| |
color index U-B: |
?
| |
color index B-V: |
?
| |
color index J-H: | 0.942 [S10b] | |
taxonomic type: |
| |
mass m: |
?
| |
density ρ: |
(1.3
g/cm3) [*A]
| |
Hill radius rH: |
1000 km [*E]
|
other data, primary:
|
diameter dp: |
6.3
± 0.4
km [K26b]
| |
rotation period RPp: |
?
| |
amplitude in mag., rotational ΔM: |
?
| |
pole direction Β, λ: |
?
,
?
|
other data, secondary:
|
diameter ds: |
2.0
± 0.5
km [K26b]
| |
diameter ratio ds/dp: |
0.32
± 0.08
[*D]
| |
component mag. difference ΔM: |
2.5
± 0.6
[*D]
| |
rotation period RPs: |
?
| |
|
|
--
(59195) 1999 BG2
--discovery and notes:
Primary discovered
1999 Jan 19
from
Catalina Station, Arizona, USA
by
Catalina Sky Survey.
Permanent number assigned 2003 Jun 14.
Companion discovered
2026 Jun 18
by S. Kidd, D. Herald, D. Gault, and C. Weber
using
stellar occultation
observations from Stevenage, Hertfordshire, United Kingdom.
Announced
2026 Jul 09 [K26b].
--Links, more technical:
--Links, less technical:
--Links to ADS abstracts:
©
2026
by Wm. Robert Johnston.
Last modified
11 July 2026.
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