C/1900 O1 (Borrelly–Brooks)

Comet Borrelly–Brooks, formal designation C/1900 O1, is a hyperbolic comet that was seen throughout the latter half of 1900.

C/1900 O1 (Borrelly–Brooks)

Comet Borrelly–Brooks photographed by H. K. Palmer on 31 July 1900[1]
Discovery
Discovered by	Alphonse Borrelly William R. Brooks
Discovery date	23 July 1900
Designations
Alternative designations	1900b[2] 1900 II
Orbital characteristics[3]
Epoch	15 August 1900 (JD 2415246.5)
Observation arc	94 days
Number of observations	121
Perihelion	1.015 AU
Eccentricity	1.00032
Orbital period	~66,000 years (inbound)
Inclination	62.533°
Longitude of ascending node	329.41°
Argument of periapsis	12.423°
Last perihelion	3 August 1900
Earth MOID	0.0154 AU
Jupiter MOID	3.0621 AU
Physical characteristics[4]
Comet total magnitude (M1)	5.0
Comet nuclear magnitude (M2)	8.0
Apparent magnitude	8.64 (1900 apparition)

Discovery and observations

French astronomer Alphonse Borrelly was the first person to discover the comet on the early morning of 24 July 1900, while William Robert Brooks independently spotted the same comet about 15 minutes later.^[4] They reported the comet as a 9th-magnitude object with a short tail located within the constellation Aries.^[a] A day later, H. K. Palmer started to take a series of photographs of the comet itself for the remainder of the month.^[1]

Robert G. Aitken was the last astronomer to observe Comet Borrelly–Brooks as it faded to a 15th-magnitude object within the constellation Ursa Minor on 23 December 1900.^[5]

Orbit

Charles D. Perrine and others calculated the first parabolic trajectory of the comet, concluding that it reached perihelion on 3 August 1900.^[6] In 1903, Manuel de Simas later revised it to a hyperbolic trajectory.^[7] J. M. Poor found that the comet had accelerated during its inbound flight to the Sun in 1900,^[8] with Brian G. Marsden and Ichiro Hasegawa later calculating this original trajectory had an orbital period of 66,000 years before it was ejected from the Solar System.^[4]

Possible meteor shower

Due to the comet's very small minimum orbit intersection distance with Earth, around 0.015 AU (2.2 million km) away, it is theorized that this comet is a potential parent body of a meteor shower that should appear 21 August of each year from a radiant in the direction of the constellation Hydrus.^[9] However, no associated meteor shower has yet been found.