1998 ST27

compiled by Wm. Robert Johnston
last updated 1 September 2005

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: 0.819353248904497 AU
orbital period P: 0.7417 y (=270.9 d)
eccentricity e: 0.530089165802822
perihelion distance q: 0.38502296869488 AU
aphelion distance Q: 1.25368353 AU
inclination i: 21.0494731140651°
argument of perihelion omega: 322.417334411007°
ascending node OMEGA: 197.616498369159°
mean anomaly M: 69.3337711632574°
perihelion passage TP: 2004-12-08.8267947
Epoch: 30 JAN 2005
data arc: 1998-2004 (303 obs.)

orbital data, secondary:
semimajor axis a: 4.5 ± 0.5 km [A3a]
<=7 km [B03a]
semimajor axis/primary radius a/Rp: 16.5 ± 3.5 [A3a]
orbital period P: ~100 h [OOa]
eccentricity e: >0.3 [B03a]

other data, primary:
diameter: 0.8 km [B03a]
absolute magnitude H: 19.49 [JPL]
rotation period: <3.1 h? [OOa]
amplitude delta M: ?
color index B-V: ?
color index V-R: ?
color index R-I: ?
slope parameter G: (0.15) [a]
geometric albedo: 0.05 [B03a]
mass: ?
density: ?
type: C [OOa]

other data, secondary:
diameter: 0.12 km [B03a]
diameter ratio Ds/Dp: (0.15) [B03a]
component magnitude difference: ?
rotation period: <6 h [B03a]

--1998 ST27--discovery and notes:

Primary discovered 24 September 1998 by the LINEAR program, Lincoln Laboratory ETS, New Mexico, USA.

Companion discovered from radar observations made 7-9 October 2001 at the Arecibo Observatory by L. A. M. Benner, M. C. Nolan, S. J. Ostro, J. D. Giorgini, and J. L. Margot; announced 9 October 2001.

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

--Links, more technical:

--Links, less technical:

--Links to ADS abstracts:


© 2002-2004, 2005 by Wm. Robert Johnston.
Last modified 1 September 2005.
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