(35671) 1998 SN165

' (provisional designation ') is a trans-Neptunian object from the Kuiper belt located in the outermost region of the Solar System. It was discovered on 23 September 1998, by American astronomer Arianna Gleason at the Kitt Peak National Observatory near Tucson, Arizona. The cold classical Kuiper belt object is a dwarf planet candidate, as it measures approximately 400 km in diameter. It has a grey-blue color (BB) and a rotation period of 8.8 hours. , it has not been named.

Orbit and classification
orbits the Sun at a distance of 36.5–39.7 AU once every 234 years and 9 months (85,755 days; semi-major axis of 38.06 AU). Its orbit has an eccentricity of 0.04 and an inclination of 5° with respect to the ecliptic. the object is at 37.2 AU, approaching the Sun until 15 July 2065, when it will come to perihelion. The body's observation arc begins at Kitt Peak in September 1998, just eight nights prior to its official discovery observation.

As a cubewano, also known as classical Kuiper belt object, is located in between the resonant plutino and twotino populations and has a low-eccentricity orbit. It belongs to the cold population, distinct from the "stirred" hot population with inclinations higher than 5°. In a previous publication, the object was originally classified as a plutino.

Numbering and naming
This minor planet was numbered by the Minor Planet Center on 27 February 2002 and received the number in the minor planet catalog (M.P.C. 44869). , it has not been named. According to the established naming conventions, it will receive a mythological or mythic name (not necessarily from Classical mythology), in particular one associated with creation.

Physical characteristics
has a blue-grey color (BB), with various color indices measured, giving a difference between the blue and red filter magnitude (BR) of 1.123 and 1.13, respectively.

Rotation period
In February 2001, a rotational lightcurve of was obtained from photometric observations by Pedro Lacerda and Jane Luu. Lightcurve analysis gave an ambiguous rotation period of 8.84 hours with a brightness amplitude of 0.16 magnitude (U=2). An alternative period of 8.70 hours is also possible.

Diameter and albedo
According to observations by the space-based Herschel and Spitzer telescopes, measures between 393 and 460 kilometers and its surface has a low albedo between 0.043 and 0.060. While Johnston's Archive adopts a diameter of 393 kilometers, astronomer Michael Brown gives a radiometric diameter of 473 kilometers and lists this object as a "probable" dwarf planet (400–500 km), which is the category with the second lowest certainty in his 5-class taxonomic system. The Collaborative Asteroid Lightcurve Link assumes an albedo of 0.10 and calculates a diameter of 334 kilometers based on an absolute magnitude of 5.5. A generic magnitude-to-diameter conversion with an albedo of 0.9 gives a diameter of 352 kilometers.