C/1958 R1 (Burnham–Slaughter)

Not to be confused with 56P/Slaughter–Burnham.

For other comets discovered by Robert Burnham Jr., see Comet Burnham.

Comet Burnham–Slaughter, also known by its modern designation C/1958 R1, is a faint non-periodic comet that was observed through telescopes between September 1958 and April 1960. It is the first of two comets that were co-discovered by Robert Burnham Jr. and Charles D. Slaughter.^[a]

C/1958 R1 (Burnham–Slaughter)

Comet Burnham–Slaughter photographed by Elizabeth Roemer from the US Naval Observatory on 10 November 1958.[1]
Discovery[2]
Discovered by	Robert Burnham Jr. Charles D. Slaughter
Discovery site	Lowell Observatory
Discovery date	7 September 1958
Designations
Alternative designations	1959 I, 1958e[3]
Orbital characteristics[4][5]
Epoch	21 April 1959 (JD 2436679.5)
Observation arc	592 days (1.62 years)
Number of observations	94
Aphelion	~27,600 AU (inbound) ~7,100 AU (outbound)
Perihelion	1.628 AU
Semi-major axis	~13,800 AU (inbound) ~3,550 AU (outbound)
Eccentricity	0.99984
Orbital period	~1.6 million years (inbound) ~210,000 years (outbound)
Inclination	61.257°
Longitude of ascending node	323.78°
Argument of periapsis	100.74°
Last perihelion	11 March 1959
TJupiter	0.761
Earth MOID	1.158 AU
Jupiter MOID	0.578 AU
Physical characteristics[6]
Comet total magnitude (M1)	13.7
Apparent magnitude	11.1 (1959 apparition)

Observational history

While conducting a proper motion survey at the Lowell Observatory on 7 September 1958, astronomers Robert Burnham Jr. and Charles D. Slaughter found a new comet using the observatory's 13 in (33 cm) telescope.^[2][6] At the time, it was a diffuse 14th-magnitude object within the constellation Equuleus.^[b] It was Burnham's third comet discovery overall after C/1957 U1 and C/1958 D1.

Elizabeth Roemer became the only astronomer to regularly observe the comet from late 1959 to early 1960.^[7] Upon her final known observation on 21 April 1960, she described the comet as a "weak but fairly sharply condensed" object at magnitude 19.7 within the constellation Hydra.^[c]

Orbit

George van Biesbroeck calculated the comet's definitive orbit in 1970, using 94 positions recorded in a time span of 592 days.^[8] Taking into account the gravitational perturbations of all the planets except Mercury, the comet has a highly parabolic elliptical orbit with an orbital period spanning millions of years, inclined about 61 degrees from the ecliptic. Forward and backward computations of its barycentric orbit in 20-year intervals by Brian G. Marsden has concluded that Burnham–Slaughter is permanently bound to the Solar System.^[8]

Additional data from JPL Horizons has indicated that the aphelion of the comet on its outbound trajectory has significantly decreased from 13,800 AU (2.06 trillion km) to 3,550 AU (531 billion km), subsequently reducing its orbital period from 1.6 million years to 210,000 years.^[4]