C/1958 R1 Burnham-Slaughter
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Comet C/1958 R1 was discovered on 7 September 1958 by Robert Burnham Jr and Charles D. Slaughter during the course of proper motion survey at Lowell Observatory (Flagstaff, Arizona,USA) [Kronk, Cometography: Volume 4], that is 6 months before its perihelion passage. C/1958 R1 was followed until 21 April 1960.

Comet had its closest approach to the Earth on 19 September 1958 (1.92 au, at this moment comet was 2.74 au from the Sun) and 18 March 1959 (1.94 au, six days after its perihelion passage).The MPC cometary database presents GR orbit based of 85 positional observations (data arc: 1958 09 07 – 1960 04 21), however only 40 observations obtained in Flagstaff are available in the MPC (data arc: 1958 09 14 – 1960 04 21), and the JPL offers GR osculating orbit based on this data set. We additionally collected observations from Yerkes, McDonald and Skalnaté Pleso observatories published in literature, and orbits 'ba' (GR) and 'bn' (NG) are based on 95 positional measurements (data arc: 1958 09 12 – 1960 04 21). For comparison purposes, we also presented orbits (GR and NG) using only Flagstaff data set (this set gives notable better rms for both types of orbits).

This is a comet with NG effects strongly manifested in positional data fitting. Solutions 'ba' and 'bn' are based on data spanning over 1.6 yr in a range of heliocentric distances: 2.81 au – 1.63 au (perihelion) – 4.92 au.

This Oort spike comet suffers moderate planetary perturbations while passing through the planetary system; these perturbations lead to more tight future orbit (see future barycentric orbits).
solution description
number of observations 40
data interval 1958 09 14 – 1960 04 21
data type perihelion within the observation arc (FULL)
data arc selection entire data set (STD)
range of heliocentric distances 2.81 au – 1.63 au (perihelion) – 4.92 au
type of model of motion NS - non-gravitational orbits for standard g(r)
data weighting NO
number of residuals 78
RMS [arcseconds] 0.66
orbit quality class 1b
previous orbit statistics, both Galactic and stellar perturbations were taken into account
no. of returning VCs in the swarm 4607 *
no. of escaping VCs in the swarm 394
no. of hyperbolas among escaping VCs in the swarm 70
previous reciprocal semi-major axis [10-6 au-1] 24.56 – 42.53 – 74.02 R
previous perihelion distance [au] 1.6 – 580 – 2300 R
previous aphelion distance [103 au] 27 – 46 – 79 R
time interval to previous perihelion [Myr] 1.6 – 3 – 7.7 R
percentage of VCs with qprev < 1037
percentage of VCs with qprev > 2063
Upper panel: Time distribution of positional observations with corresponding heliocentric (red curve) and geocentric (green curve) distance at which they were taken. The horizontal dotted line shows the perihelion distance for a given comet whereas vertical dotted line — the moment of perihelion passage.
Middle panel(s): O-C diagram for a given solution (sometimes in comparison to another solution available in CODE), where residuals in right ascension are shown using magenta dots and in declination by blue open circles.
Lowest panel: Relative weights for a given data set(s).
previous_g orbit statistics, here only the Galactic tide has been included
no. of returning VCs in the swarm 4525 *
no. of escaping VCs in the swarm 476
no. of hyperbolas among escaping VCs in the swarm 79
previous reciprocal semi-major axis [10-6 au-1] 25.91 – 48.05 – 74.27 R
previous perihelion distance [au] 1.8 – 2.6 – 35 R
previous aphelion distance [103 au] 27 – 42 – 77 R
time interval to previous perihelion [Myr] 1.6 – 3 – 7.5 R
percentage of VCs with qprev < 1079
percentage of VCs with 10 < qprev < 207
percentage of VCs with qprev > 2014