Rahul Sharma (Editor)

(26308) 1998 SM165

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Discovered by  Nichole M. Danzl
MPC designation  (26308) 1998 SM165
Minor planet category  twotino Kozai
Orbital period  328 years
Inclination  13.5226°
Orbits  Sun
Discovery date  16 September 1998
Alternative names  none
Observation arc  9952 days (27.25 yr)
Discovered  16 September 1998
Argument of perihelion  130.56°
Discoverer  Nichole M. Danzl
(26308) 1998 SM165

Discovery site  Kitt Peak National Observatory

26308 1998 sm165

(26308) 1998 SM165, also written as (26308) 1998 SM165, is a binary trans-Neptunian object (TNO) that resides in the Kuiper belt. It was discovered on September 16, 1998, by Nichole Danzl. It is in a 1:2 orbital resonance with the planet Neptune.



1998 SM165 has a semi-major axis (average distance from the Sun) near the edge of the classical belt. Both the Minor Planet Center (MPC) and the Deep Ecliptic Survey (DES) list this trans-Neptunian object as a twotino. For every one orbit that a twotino makes, Neptune orbits twice.

Physical characteristics

The observations with the infrared Spitzer Space Telescope combined with the orbits established using the Hubble Telescope allow the estimation of the density, assuming the components of equal albedo.

The resulting estimate of 7002510000000000000♠0.51+0.29
is similar to the density of the binary plutino (47171) 1999 TC36 (0.3–0.8 g/cm3) and Saturn’s moon Hyperion (7002567000000000000♠0.567±0.102 g/cm3) Such a low density is indicative of a highly porous composition dominated by ice.

(26308) 1998 SM165 is fairly red, with a color comparable to 79360 Sila–Nunam.


Designated S/2001 (26308) 1, it is about 96 ± 12 km (59.7 ± 7.5 mi) in diameter and it orbits its primary at a distance of 11,310 ± 110 km (7,028 ± 68 mi). Assuming a circular orbit, this takes 7002130100000000000♠130.1±1 days to complete one orbit.


(26308) 1998 SM165 Wikipedia