(79360) Sila-Nunam

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: 43.939069 AU
orbital period P: 291.26 y (=106,383.61 d)
eccentricity e: 0.011162785
perihelion distance q: 43.448587 AU
aphelion distance Q: 44.429552 AU
inclination i: 2.241799°
argument of perihelion omega: 214.691161°
ascending node OMEGA: 304.340046°
mean anomaly M: 334.593196°
perihelion passage TP: 2032-10-02.97
Epoch: 14 MAR 2012
data arc: 1997-2011 (209 obs.)

orbital data, secondary:
semimajor axis a: 2,777 ± 19 km [G12b]
semimajor axis/primary radius a/Rp: (22)
orbital period P: 12.50995 ± 0.00036 d [G12b]
eccentricity e: 0.020 ± 0.015 [G12b]
inclination i: 103.51 ± 0.39 [G12b]
argument of periapsis omega: 326° ± 59° [G12b]
ascending node OMEGA: 140.76° ± 0.66° [G12b]
mean anomaly M: 16.3° ± 1.0° [G12b]

other data, primary:
diameter: 343 ± 42 km combined [G12b]
250 km ± 30 km [G12b]
absolute magnitude H: 5.51 ± 0.02 [G11a]
rotation period: ?
amplitude delta M: ?
color index B-V: 1.08 ± 0.03 [B05c]
color index V-R: 0.66 ± 0.04 [B05c]
color index V-I: 1.25 ± 0.03 [B05c]
color index V-J: 2.06 ± 0.03 [B05c]
color index V-H: 2.45 ± 0.08 [B05c]
color index H-K: 0.28 ± 0.23 [B01a]
slope parameter G: (0.15) [a]
geometric albedo: 0.086 ± 0.026/0.017 V [G12b]
0.117 ± 0.035/0.024 V [G12b]
mass (system): (1.084 ± 0.022) x 1019 kg [G12b]
density: 0.72 +0.37/-0.23 g/cm3 [G12b]
BBFB type: RR [B05c]

other data, secondary:
diameter: 236 ± 28 km [G12b]
diameter ratio Ds/Dp: (0.95)
component magnitude difference: 0.12 [G11a]
rotation period: ?

--(79360) 1997 CS29--discovery and notes:

Primary discovered 3 February 1997 by J. X. Luu, D. C. Jewitt, C. A. Trujillo, and J. Chen from Mauna Kea observatory. Permanent number assigned 4 May 2004, name assigned 9 January 2012. Provisional designation 1997 CS29.

Companion discovered by Denise C. Stephens and Keith S. Noll from Hubble Space Telescope observations of 22 October 2002; announced 5 October 2005. W. M. Grundy et al., based on their orbit solution for the binary, report that mutual occultation/eclipses may occur over the period October 2011-May 2013.

Sila and Nunam are expected to undergo a series of mutual events from 24 October 2012 to 6 May 2013. [G12b]

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

--Links, more technical:

--Links, less technical:

--Links to ADS abstracts:


© 2005, 2012 by Wm. Robert Johnston.
Last modified 3 November 2012.
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