C/1961 R1 (Humason)
Comet Humason (Palomar) September 4, 1962.jpg
Comet Humason on September 4, 1962, by Palomar Observatory
Discovered byMilton L. Humason
Discovery date1961-Sep-01
Orbital characteristics
Aphelion406.91 AU
Perihelion2.1334 AU (q)
Orbital period2883 years (barycentric inbound)
2516 years (barycentric outbound)
Last perihelion1962-Dec-10[1]
Physical characteristics

Comet Humason, formally designated C/1961 R1 (a.k.a. 1962 VIII and 1961e), was a non-periodic comet discovered by Milton L. Humason on September 1, 1961. Its perihelion was well beyond the orbit of Mars, at 2.133 AU. The outbound orbital period is about 2516 years. The diameter of its comet nucleus is estimated at around 30−41 km.[2]

It was a "giant" comet, much more active than a normal comet for its distance to the Sun, with an absolute magnitude of 1.5−3.5, it could have been up to a hundred times brighter than an average new comet. It had an unusually disrupted or "turbulent" appearance.[3] It was also unusual in that the spectrum of its tail showed a strong predominance of the ion CO+, a result previously seen unambiguously only in Comet Morehouse (C/1908 R1).[4]


  1. ^ "JPL Small-Body Database Browser: C/1961 R1 (Humason)" (last observation: 1965-11-01). Jet Propulsion Laboratory. Retrieved 2019-05-29.
  2. ^ a b "Comets: Comet Humason 1961e". Irish Astronomical Journal. 6: 191. 1964. Bibcode:1964IrAJ....6Q.191.
  3. ^ Brandt & Chapman. Introduction to Comets. Cambridge University Pressyear=2004. p. 156.
  4. ^ Huebner, W. (1990). Physics and chemistry of comets. Springer-Verlag. p. 246.