[3] The discovery was made in a survey of faint Trojans (in spite of not having received a typical T-1 designation).
[1] The trio of Dutch and Dutch–American astronomers collaborated on the productive Palomar–Leiden survey in the 1960s, using the same procedure as for this smaller Trojan campaign: Gehrels used Palomar's Samuel Oschin telescope (also known as the 48-inch Schmidt Telescope), and shipped the photographic plates to Cornelis and Ingrid van Houten at Leiden Observatory where blinking and astrometry was carried out.
[6] It orbits the Sun in the outermost main-belt at a distance of 3.1–4.8 AU once every 7 years and 10 months (2,861 days).
[4][6] During a photometric survey of Hilda asteroids in the late 1990s, an obtained light curve for Marsden gave a rotation period of 14.4 hours with a brightness variation of 0.22 in magnitude (U=2).
[7] According to the surveys carried out by the Japanese Akari satellite and NASA's Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, Marsden measures 35.27 and 35.643 kilometers in diameter and its surface has an albedo of 0.082 and 0.07, respectively.