Asteroids with Satellites Database--Johnston's Archive
(2478)
Tokai
compiled by Wm. Robert Johnston
last updated
21 September 2014
--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: |
2.225290189 AU
| |
orbital period P: |
3.319618544 yr
(= 1212.4906730 d)
| |
eccentricity e: |
0.068326263
| |
perihelion distance q: |
2.073244426 AU
| |
aphelion distance Q: |
2.377335952 AU
| |
inclination i: |
4.1377104°
| |
argument of perihelion ω: |
233.299096°
| |
ascending node Ω: |
228.827934°
| |
mean anomaly M: |
107.605718°
| |
perihelion passage TP: |
2013 May 25.5807
| |
Epoch: |
2014 May 23
| |
data arc: |
1932-2014
(1353 obs.)
| |
Earth MOID: |
1.09268 AU
| |
Jupiter Tisserand invariant TJ: |
3.64
|
orbital data, secondary:
|
semimajor axis as: |
21
km
[*E]
| |
separation/primary radius as/rp: | 5.2 [*E] | |
separation/Hill radius as/rH: | 0.014 [*E] | |
orbital period Ps: |
1.079
± 0.00029
d [H07c]
| |
eccentricity es: |
?
| |
normalized ang. mom. αL: |
?
|
|
other data, system (combined):
|
absolute mag. H: |
12
[MPC]
| |
slope parameter G: |
(0.15) [*A]
| |
effective diameter dE: |
9.98
± 0.03
km [M11b]
| |
geometric albedo: |
0.208
± 0.037
[M11b]
| |
color index U-B: |
?
| |
color index B-V: |
?
| |
taxonomic type: |
S (SMASSII) [JPL]
| |
mass m: |
?
| |
density ρ: |
(1.6
g/cm3) [*A]
| |
Hill radius rH: |
1500 km [*E]
|
other data, primary:
|
diameter dp: |
8.1
± 0.02
km [*D]
| |
rotation period RPp: |
25.885
± 0.007
h [H07c]
| |
amplitude in mag., rotational ΔM: |
0.41
[H07c]
| |
pole direction Β, λ: |
?
,
?
|
other data, secondary:
|
diameter ds: |
5.83
km [*D]
| |
diameter ratio ds/dp: |
>0.72
[H07c]
| |
component mag. difference ΔM: |
<0.71
[*D]
| |
rotation period RPs: |
25.885
± 0.007
h [H07c]
| |
|
|
--
(2478) Tokai
--discovery and notes:
Primary discovered
1981 May 04
from
Tokai, Japan
by
T. Furuta.
Alternate designation(s):
1981 JC,
1931 HH, 1932 SE, 1934 ED, 1939 VH, 1951 JP, 1955 OE, 1955 QV, 1957 BD, 1972 RS, 1978 NU2, 1979 XR, 1981 JT.
Linked to prediscovery observations from 1932 Sep 30.
Permanent number assigned 1981 Nov 11.
Named 1982 Feb 08 for the city of Tokai, Aichi, Japan [MPC6650].
Companion discovered
2007 Jan 20
by D. Higgins, P. Pravec, P. Kusnirak, B. Warner, A. Galad, J. Oey, R. Gonclaves, W. Cooney, J. Gross, and D. Terrell
using
lightcurve
observations from Canberra, Australia; Ondrejov Observatory, Czech Republic; Palmer Divide Observatory, Colorado Springs, Colorado; Modra Observatory, Slovakia; Leura, NSW, Australia; Linhaceira, Tomar, Portugal; Sonoita Research Observatory, Sonoita, Arizona, USA.
Announced
2007 Jan 30 [H07c].
--Links, more technical:
--Links, less technical:
--Links to ADS abstracts:
- Higgins, D., Pravec, P., Kusnirak, P., Warner, B., Galad, A., Oey, J., Goncalves, R., Cooney, W., Gross, J., & Terrell, D. 2007, Central Bureau Electronic Telegrams (2478) Tokai
- Bus, S. & Binzel, R. P. 2004, NASA Planetary Data System 2478 Tokai CCD Spectrum
©
2007-2009, 2014
by Wm. Robert Johnston.
Last modified
21 September 2014.
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