(47171) 1999 TC36, S/2001 (47171) 1, and third component

compiled by Wm. Robert Johnston
last updated 6 December 2009

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: 39.2280453217444 AU
orbital period P: 245.6989 y (=89743 d)
eccentricity e: 0.221336017210763
perihelion distance q: 30.5454660072662 AU
aphelion distance Q: 47.91062464 AU
inclination i: 8.41541631958719°
argument of perihelion omega: 295.351141968415°
ascending node OMEGA: 97.1231020762021°
mean anomaly M: 344.706976754838°
perihelion passage TP: 2015-07-09.2754936
Epoch: 30 JAN 2005
data arc: 1999-2003 (85 obs.)

orbital data, secondary:
semimajor axis a: 7,640 ± 460 km [M04b]
7,720 km [S06a]
semimajor axis/primary radius a/Rp: (40)
orbital period P: 50.38 ± 0.5 d [M04b]
eccentricity e: ?

orbital data, third component:
semimajor axis a: 867 km [B09c]
semimajor axis/primary radius a/Rp: (6)
orbital period P: 1.9 d [B09c]
eccentricity e: ?

other data, primary:
diameter: 379 (± 61/51) km [S06a]
281 (± 45/38) km [B09c]
absolute magnitude H: 4.73 [JPL]
rotation period: >8 h? [P02b]
6.21 h? [O03b]
1.9 d? [B09c]
amplitude delta M: <0.07 [L06a]
0.06? [O03b]
color index B-V: 1.01 ± 0.04 [B05c]
color index V-R: 0.69 ± 0.03 [B05c]
color index R-I: 0.63 ± 0.05 [B05c]
color index V-J: 2.32 ± 0.07 [M03a]
color index V-H: 2.74 ± 0.03 [B05c]
slope parameter G: (0.15) [a]
geometric albedo: 0.079 ±0.031/0.024 [S06a]
mass (system): (1.39 ± 0.25)x1019 kg [M04b]
(1.44 ± 0.22)x1019 kg [S06a]
density: 0.5 ± 0.3/0.2 g/cm3 [S06a]
type: P [M03a]
BBFB type: RR [B05c]

other data, secondary:
diameter: 142 (± 23/19) km [S06a]
135 (± 22/18) km [B09c]
diameter ratio Ds/Dp: (0.374 ± 0.004) [M05b]
component magnitude difference: (2.14) [M05b]
rotation period: ?
other data, third component:
diameter: 258 (± 41/35) km [B09c]
diameter ratio Ds/Dp: (0.92) [B09c]
component magnitude difference: (0.18) [B09c]
rotation period: (1.9 d?)

--(47171) 1999 TC36--discovery and notes:

Primary discovered 1 October 1999 by E. P. Rubenstein and L.-G. Strolger from Kitt Peak, Arizona, USA.

Secondary discovered from 8 December 2001 observations by C. A. Trujillo and M. E. Brown using the Hubble Space Telescope; announced 10 January 2002.

The primary was itself hypothesized as binary in 2005 based on lightcurve observations. Analysis of Hubble Space Telescope imagery by Seth Jacobson and J. L. Margot showed the primary to be elongated in a manner best explained if it was two unresolved components; results announced October 2007. This was confirmed in 2009 based on further analysis of Hubble Space Telescope imagery by Susan D. Benecchi, K. S. Noll, W. M. Grundy, and H. F. Levison, results announced September 2009.

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

--Links, more technical:

--Links, less technical:

--Links to ADS abstracts:


© 2003-2006, 2009 by Wm. Robert Johnston.
Last modified 6 December 2009.
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