Asteroids with Satellites Database--Johnston's Archive
(1757)
Porvoo
compiled by Wm. Robert Johnston
last updated
23 September 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: |
2.35198313247 AU
| |
orbital period P: |
3.60711099686 yr
(= 1317.4972916 d)
| |
eccentricity e: |
0.12474114511
| |
perihelion distance q: |
2.05859406324 AU
| |
aphelion distance Q: |
2.64537220169 AU
| |
inclination i: |
3.969644403°
| |
argument of perihelion ω: |
149.27464031°
| |
ascending node Ω: |
39.34708578°
| |
mean anomaly M: |
57.85363825°
| |
perihelion passage TP: |
2025 Nov 09.2721897
| |
Epoch: |
2026 Jun 09
| |
data arc: |
1939-2026
(7354 obs.)
| |
Earth MOID: |
1.06058 AU
| |
Jupiter Tisserand invariant TJ: |
3.543
|
orbital data, secondary:
|
semimajor axis as: |
27.5
km
(separation)
[L26c]
| |
separation/primary radius as/rp: | 4.2 [*E] | |
separation/Hill radius as/rH: | 0.013 [*E] | |
orbital period Ps: |
0.93
d [*E]
| |
eccentricity es: |
?
| |
normalized ang. mom. αL: |
?
|
|
other data, system (combined):
|
absolute mag. H: |
13.56
[MPC]
| |
slope parameter G: |
(0.15) [*A]
| |
effective diameter dE: |
12.81
± 0.45
km [U11a]
| |
geometric albedo: |
0.049
± 0.004
[U11a]
| |
color index U-B: |
?
| |
color index B-V: |
?
| |
color index J-H: | 0.554 ± 0.097 [S10b] | |
taxonomic type: |
?
| |
mass m: |
?
| |
density ρ: |
(1.6
g/cm3) [*A]
| |
Hill radius rH: |
2100 km [*E]
|
other data, primary:
|
diameter dp: |
13.1
km [L26c]
| |
dimensions : | 15.9 x 10.8 km [L26c] | |
rotation period RPp: |
4.89
h [JPL]
| |
amplitude in mag., rotational ΔM: |
?
| |
pole direction Β, λ: |
?
,
?
|
other data, secondary:
|
diameter ds: |
1.85
± 0.75
km [L26c]
| |
diameter ratio ds/dp: |
0.14
[*D]
| |
component mag. difference ΔM: |
4.3
[*D]
| |
rotation period RPs: |
?
| |
|
|
--
(1757) Porvoo
--discovery and notes:
Primary discovered
1939 Mar 17
from
Turku, Finland
by
Y. Vaisala.
Alternate designation(s):
1939 FC,
1964 BB, 1968 FK.
Named 1980 Aug 01 for the town in Finland [MPC005449].
Companion discovered
2026 Jul 07
by B. Lade, A. Wendelborn, P. Martinaitis, D. Herald, D. Gault, and B. Anderson
using
stellar occultation
observations from Mawson Lakes, South Australia, Australia; Largs North, South Australia, Australia; Salisbury, South Australia, Australia.
Announced
2026 Sep 22 [L26c].
--Links, more technical:
--Links, less technical:
--Links to ADS abstracts:
©
2026
by Wm. Robert Johnston.
Last modified
23 September 2026.
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