2685 Masursky

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2685 Masursky
Asteroid 2685Masurky.png
Masursky as seen by Cassini with identification arrow
Discovered by Edward L. G. Bowell
Discovery date 3 May 1981
Named after
Harold Masursky
1950 VO; 1973 QF;
1975 XJ5; 1977 KU;
1981 JN
Main belt (Eunomia family)
Orbital characteristics[1]
Epoch 13 January 2016 (JD 2457400.5)
Uncertainty parameter 0
Observation arc 15469 days (42.35 yr)
Aphelion 2.85094 AU (426.495 Gm)
Perihelion 2.28780 AU (342.250 Gm)
2.56937 AU (384.372 Gm)
Eccentricity 0.10959
4.12 yr (1504.3 d)
18.53 km/s
Inclination 12.1269°
Earth MOID 1.3315 AU (199.19 Gm)
Jupiter MOID 2.2439 AU (335.68 Gm)
Physical characteristics
Dimensions 15–20 km
Mass 0.5–1.1×1016 kg
Mean density
~2.7 g/cm³ (estimate)[2]
Equatorial surface gravity
0.006–0.007 m/s²
Equatorial escape velocity
0.009–0.012 km/s
Temperature ~176 K
max: 264 K (−9° C)

The asteroid 2685 Masursky is a main-belt asteroid. It was discovered by Edward (Ted) Bowell in 1981. It was named after Harold Masursky (1923–1990), a planetary geologist at the U.S. Geological Survey, Flagstaff, who worked on numerous space missions.

Little was known about Masursky until the Cassini space probe, en route to Jupiter and Saturn, flew past it on 23 January 2000. Because Cassini passed the asteroid at a distance of 1.6 million kilometres (about four times the EarthMoon distance), the images it returned showed nothing more than a dot. Nevertheless, Cassini was able to determine Masursky's size, about 15–20 km in diameter.[3] The asteroid was between 0.81 and 1.08 arcseconds in apparent diameter.

Masursky's orbit places it within the Eunomia family of S-type asteroids. Cassini's observations had cast some doubt on its composition, but later ground-based spectroscopy has confirmed its S-type spectrum.[4]


  1. ^ "JPL Small-Body Database Browser: 2685 Masursky (1981 JN)". Jet Propulsion Laboratory. Retrieved 25 March 2016. 
  2. ^ G. A. Krasinsky et al. Hidden Mass in the Asteroid Belt, Icarus, Vol. 158, p. 98 (2002).
  3. ^ NASA/JPL. "PIA02449 info page". Retrieved 19 July 2013. 
  4. ^ D. Lazzaro; T. Mothé-Diniz; J. M. Carvano; C. A. Angeli; A. S. Betzler; M. Florczak; et al. (1999). "The Eunomia Family: A Visible Spectroscopic Survey". Icarus. 142 (2): 445. Bibcode:1999Icar..142..445L. doi:10.1006/icar.1999.6213. 

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