C/1959 Y1 (Burnham)

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

Comet Burnham, formally designated as C/1959 Y1, is a hyperbolic comet that became visible to the naked eye in 1960.^[5] It is one of six comets discovered by American astronomer, Robert Burnham Jr.^[2] It brightened up to a magnitude of 3.5.^[6]

C/1959 Y1 (Burnham)

Comet Burnham photographed by Alan McClure on 22 April 1960.[1]
Discovery[2]
Discovered by	Robert Burnham Jr.
Discovery site	Lowell Observatory
Discovery date	30 December 1959
Designations
Alternative designations	1960 II, 1959k[3]
Orbital characteristics[4]
Epoch	4 April 1960 (JD 2437028.5)
Observation arc	148 days
Number of observations	35
Perihelion	0.5044 AU
Eccentricity	1.00029
Inclination	159.601°
Longitude of ascending node	252.643°
Argument of periapsis	306.632°
Last perihelion	20 March 1960
Earth MOID	0.1947 AU
Jupiter MOID	0.5355 AU
Physical characteristics[5]
Comet nuclear magnitude (M2)	15.9
Apparent magnitude	3.5 (1960 apparition)

Observational history

The comet was discovered in a photographic plates obtained by the Lowell Observatory in Arizona as part of the Lowell Proper Motion Survey program on 29−30 December 1959. Robert Burnham Jr. noticed in one of them a fairly bright, diffuse trail. He estimated its apparent magnitude to be 11. The presence of the comet was confirmed by Lick Observatory on 1 and 2 January 1960, and by Lowell observatory on 2 January. Henry L. Giclas, Lowell observatory, estimated its magnitude to be 14. The comet then was three months before perihelion and 1.71 AU from the Sun.^[7]

The comet appeared moderately condensed in images obtained in early January, but the central condensation became more pronounced by the end of the month. On 28 January Elizabeth Roemer reported that the comet has a coma 1.3' across, and two tails, one short, curved tail extending 3' long, and a narrow, straight tail 15' long. On 9 March the comet reached its minimum elongation, being 8 degrees from the Sun, and continued to move southwards until 21 March, reaching a declination of -13°. The perihelion of the comet was on 20 March 1960.^[7]

The comet was recovered on 25 March in the morning twilight. Its magnitude was estimated visually by Roemer to be 7 on 4 April. In the start of April no tail was visible visually, but Alan McClure detected a very faint tail 3 degrees long in a photographic plate obtained in blue light. The comet was brightening as it was approaching Earth. On April 13 George van Biesbroeck estimated its magnitude to 5.3 and on April 18 to be 4.7. On April 22 the tail was reported to be 2.5° long visually and 7.4° in photographic plates exposed in blue light. The comet was reported to have reached an apparent magnitude of 3.5 on April 26. Closest approach took place on April 27, at a distance of 0.20 AU.^[7]

After the perigee, the comet faded rapidly and on 1 May van Biesbroeck estimated its magnitude to be 4.8. On May 3 its photographic magnitude was estimated to be 6.5 by Arend, while a tail was also imaged. On May 14 the photographic magnitude had dropped to 10. The comet was last detected in images obtained on 17 June by Roemer at the US Naval Observatory. It was descripted as essentially stellar with a magnitude of 18.^[7]