C/1961 R1 (Humason)

Not to be confused with another long-period comet with the same name: C/1960 M1 (Humason).

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 1 September 1961. Its perihelion was well beyond the orbit of Mars, at 2.133 AU. The outbound orbital period is about 2,516 years.

C/1961 R1 (Humason)

Comet Humason photographed from the Palomar Observatory on 4 September 1962
Discovery
Discovered by	Milton L. Humason
Discovery date	1 September 1961
Designations
Alternative designations	1961e 1962 VIII
Orbital characteristics[1]
Epoch	12 May 1963 (JD 2438161.5)
Observation arc	1,517 days (4.15 years)
Number of observations	80
Aphelion	408.71 AU
Perihelion	2.133 AU
Semi-major axis	205.42 AU
Eccentricity	0.98961
Orbital period	2,883 years (inbound) 2,516 years (outbound)
Inclination	153.278°
Longitude of ascending node	155.439°
Argument of periapsis	233.562°
Last perihelion	10 December 1962
TJupiter	–1.588
Earth MOID	1.2247 AU
Jupiter MOID	1.0725 AU
Physical characteristics[2][3]
Dimensions	30–41 km (19–25 mi)
Comet total magnitude (M1)	1.35–3.5
Comet nuclear magnitude (M2)	10.1

Physical properties

It was a "giant" comet, much more active than a normal comet for its distance to the Sun, with an absolute magnitude of 1.35−3.5,^[3] and a nucleus diameter estimated at 30–40 km (19–25 mi).^[2] It could have been up to a hundred times brighter than an average new comet. It had an unusually disrupted or "turbulent" appearance.^[4] 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 C/1908 R1 (Morehouse).^[5]

See also

• C/1729 P1 (Sarabat)
• C/1995 O1 (Hale–Bopp)
• C/2014 UN₂₇₁ (Bernardinelli–Bernstein)