16P/Brooks

16P/Brooks
Discovery
Discovered by	William Robert Brooks
Discovery date	7 July 1889
Designations
Alternative designations	1889 V; 1896 VI; 1903 V;; 1911 I; 1925 IX; 1932 VIII;; 1939 VII; 1946 IV; 1953 V;; 1960 VI; 1974 I; 1980 IX;; 1987 XXIV; 1994 XXIII
Orbital characteristics
Epoch	2023-02-25
Aphelion	5.439 AU
Perihelion	1.879 AU
Semi-major axis	3.659 AU
Eccentricity	0.4864
Orbital period	6.99 yr
Max. orbital speed	40 km/s (1886 Jupiter approach); 26 km/s (2028 perihelion)
Inclination	3.011°
Last perihelion	April 18, 2021; June 7, 2014; April 12, 2008
Next perihelion	2028-Apr-21

16P/Brooks, also known as Brooks 2, is a periodic comet discovered by William Robert Brooks on July 7, 1889, but failed to note any motion. He was able to confirm the discovery the next morning, having seen that the comet had moved north. On August 1, 1889, the famous comet hunter Edward Emerson Barnard discovered two fragments of the comet labeled "B" and "C" located 1 and 4.5 arc minutes away. On August 2, he found another four or five, but these were no longer visible the next day. On August 4, he observed two more objects, labeled "D" and "E". "E" disappeared by the next night and "D" was gone by the next week. Around mid-month, "B" grew large and faint, finally disappearing at the beginning of September. "C" managed to survive until mid-November 1889. The apparition ended on January 13, 1891. After the discovery apparition, the comet has always been over two magnitudes fainter.

1886

The comet's breakup is believed to have been caused by the passage of the comet within Jupiter's Roche limit around 20 July 1886,^[5]^[4]^[a] when it spent two days within the orbit of Io.^[b]

16P/Brooks 2 best-fit Jupiter approach around 1886-Jul-20^[5]
Date & time of closest approach	Jupiter distance (AU)	Sun distance (AU)	Velocity wrt Jupiter (km/s)	Velocity wrt Sun (km/s)	Reference
1886-Jul-20 22:32	0.001 AU (150 thousand km; 93 thousand mi; 0.39 LD)	5.457 AU (816 million km; 507 million mi)	41.1	40.1	Horizons

The very close approach to Jupiter in 1886 resulted in the previous perihelion distance becoming the new aphelion distance.

Orbital Elements for 1865 + 1889^[6]
Epoch	Aphelion (AD)	Perihelion (QR)	Period
1865	14 AU^[c]	5.5 AU	31 years
1889	5.4 AU	1.95 AU	7 years

On 31 December 2016 the comet passed 0.333 AU (49.8 million km) from Jupiter and on 5 July 2053 ± 3 days it will pass about 0.26 AU (39 million km) from Jupiter.^[7]

Notes

^ Jupiter came to aphelion (farthest distance from the Sun) one month later on 1886-Aug-21 at 5.4568 AU.
^ Io orbits 0.0028 AU (420 thousand km) from Jupiter.
^ 16P/Brooks came to aphelion (farthest distance from the Sun) around 1870 at ≈14.3 AU.