(42355) Typhon and Echidna

compiled by Wm. Robert Johnston
last updated 3 November 2012

Orbital elements and other data (Assumed or derived values in parenthesis, my estimates in italics and parenthesis. Source identifications in brackets, see this link for sources):

orbital data, primary (osculating elements) [JPL]:
semimajor axis a: 38.162506 AU
orbital period P: 235.760 y (=86,110.0 d)
eccentricity e: 0.5407609
perihelion distance q: 17.525714 AU
aphelion distance Q: 58.799297 AU
inclination i: 2.4280935°
argument of perihelion omega: 159.0020803°
ascending node OMEGA: 351.9923803°
mean anomaly M: 359.6998644°
perihelion passage TP: 2006-05-16.79
Epoch: 06 MAR 2006
data arc: 1989-2006 (115 obs.)

orbital data, secondary:
semimajor axis a: 1,628 ± 29 km [G08a]
semimajor axis/primary radius a/Rp: (24)
orbital period P: 18.9709 ± 0.0064 d [G08a]
eccentricity e: 0.526 ± 0.015 [G08a]
inclination i: 37.9° ± 2.0° to J2000 eq. [G08a]
longitude of periapsis : 352.1° ± 1.4° [G08a]
ascending node OMEGA: 253.1° ± 4.0° [G08a]
mean long. : 11.5° ± 1.6° [G08a]
orbit pole : RA = 163.0° ± 4.5°; dec = 52.2° ± 2.3° [G08a]

other data, primary:
diameter: (138 km) [S12b]
absolute magnitude H: 7.65 ± 0.01 [T03b]
rotation period: 3.66 h or 4.35 h ± 0.02 h [O03b]
>5 h [D08a]
amplitude delta M: ?
color index B-V: 0.74 ± 0.02 [T03b]
color index V-R: 0.52 ± 0.01 [T03b]
color index V-I: 0.99 ± 0.04 [G08a]
slope parameter G: (0.15) assumed
geometric albedo: 0.0600 +0.0410/-0.0208 [S12b]
mass: (9.49 ± 0.52) x 1017 kg [G08a]
density: 0.60 +0.72/-0.29 g/cm3 [S12b]
type: ?

other data, secondary:
diameter: (76 km) [S12b]
diameter ratio Ds/Dp: (0.55)
component magnitude difference: 1.30±0.06 [G08a]
rotation period: ?
color index V-I: 0.95 ± 0.04 [G08a]

--(42355) Typhon--discovery and notes:

Primary discovered 5 February 2002 from Palomar Observatory, California, USA, by the JPL/GEODSS NEAT Program. Linked to prediscovery observations from 1989. Preliminary designation 2002 CR46, name assigned 9 November 2006.

Companion discovered by Keith S. Noll, Harold F. Levison, W. M. Grundy, and Denise C. Stephens from Hubble Space Telescope observations on 20 January 2006, announced 15 February 2006. Name assigned November 2006

See more information and links at Asteroid/Comet Connection Catchall Catalog page

--Links, more technical:

--Links, less technical:

--Links to ADS abstracts:


© 2006-2008, 2012 by Wm. Robert Johnston.
Last modified 3 November 2012.
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