C/1890 F1 Brooks

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C/1890 F1 Brooks

General description

Comet C/1890 F1 Brooks (called comet 1890a or 1890I at that time) was discovered at the Smith Observatory, Geneva, N.Y., USA by William Robert Brooks on 1890 March 19 (March 20 UT) at a heliocentric distance of 2.1 AU and 2.7 AU from the Earth. During the first days of June 1890 the comet reached its perihelion at a distance of 1.91 AU from the Sun (on June 2) and the day after — the closest distance of 1.57 AU from the Earth. Comet Brooks was followed far after the perihelion passage (1.9 AU) to about 6.7 AU from the Sun. Stéphane Javelle (Nice Observatory) was the only observer who followed the comet after the seven-month gap in data due to comet’s conjunction with the Sun. In 1892, he took nine measurements spanning a period from January 7 to February 5. It is obvious that these observations are very important for orbit determination.

Figure caption: Time distribution of positional observations with corresponding heliocentric (magenta curve) and geocentric (turquoise 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.

Background: Comet C/1890 F1 Brooks belongs to nineteen comets used by Jan Oort to support his famous hypothesis on the existence of a spherical cloud containing hundreds of billions of comets moving on orbits of semimajor axes between 50000 and 150000 AU around the sun.

More details in Królikowska and Dybczyński, 2016

Supplementary materials at WikiComet

Figure caption: The overall view on cometary track of Comet Brooks filled by collected astrometric observations in geocentric equatorial coordinate system given in Aitoff projection. Declination is plotted along the ordinate, right ascension is plotted along the abscissa (increasing from 0° to 360° from the left to right) and the centre of projection is 0° of declination and 180° of right ascension. The lines of right ascension and declination are shown at 30° intervals and the wavy line shows the projection of the ecliptic onto the celestial sphere. Each positional observation before perihelion passage are shown as a dark turquoise point, except the first observation that is shown by a dark magenta point whereas the data taken after perihelion passage are given by light turquoise points.

SSDP Cometary Note C1890F1Z6_Tycho-001 Astrometric data used for orbit determination

Comet C/1890 F1 Brooks

number of observations	908
number of residuals	1644
data interval	1890 Mar. 22 — 1892 Feb. 5
rms [arcsec]	2.61
orbit quality class	1a

Osculating orbital elements (heliocentric; ecliptic J2000.0)

Epoch (TT)	18900602.0	= JD 2411520.5
time of perihelion passage (TT)	18900602.037682	± 0.000236
perihelion distance [au]	1.90758152	± 0.00000173
eccentricity	1.00033162	± 0.00000658
argument of perihelion [deg]	68.927751	± 0.000116
longitude of the ascending node [deg]	321.877680	± 0.000037
inclination [deg]	120.568896	± 0.000037
inverse semimajor axis [10^-6 au^-1]	-173.84	± 3.45

Note: Epoch is given in a format: yyyymmdd.d, time of perihelion passage in a format of yyyymmdd.dddddd.

Figure caption: Six 2D-projections of the 6D space of original swarm (5001 VCs) of C/1890 F1. Each density map is given in logarithmic scale presented on the right in the individual panel.
The same figure in the new window

Original orbital elements (barycentric; at 250 au from the Sun)

Epoch (TT)	15900106
time of perihelion passage (TT)	18900601.440026	± 0.000267
perihelion distance [au]	1.90269415	± 0.00000172
eccentricity	0.99989655	± 0.00000651
argument of perihelion [deg]	69.063223	± 0.000115
longitude of the ascending node [deg]	321.902338	± 0.000037
inclination [deg]	120.564184	± 0.000037
inverse semimajor axis [10^-6 au^-1]	54.37	± 3.42

Note: Values of uncertainties of original/future orbital elements were derived using a swarm of 5001 osculating orbits of VCs (including the nominal osculating orbit given above) for original/future orbital evolution calclulations and then by fitting the distribution of a given orbital element of original/future swarm of VCs to Gaussian distribution.

Original barycentric positions and velocities of 5001 VCs at 250 au from the Sun are given here (data format), i.e. before entering the planetary zone.

Figure caption: Six 2D-projections of the 6D space of future swarm (5001 VCs) of C/1890 F1. Each density map is given in logarithmic scale presented on the right in the individual panel.
The same figure in the new window

Future orbital elements (barycentric; at 250 au from the Sun)

Epoch (TT)	21910224
time of perihelion passage (TT)	18900602.517267	± 0.000205
perihelion distance [au]	1.90422364	± 0.00000174
eccentricity	0.99982638	± 0.00000651
argument of perihelion [deg]	68.848991	± 0.000115
longitude of the ascending node [deg]	321.904687	± 0.000037
inclination [deg]	120.537491	± 0.000037
inverse semimajor axis [10^-6 au^-1]	91.18	± 3.42

Future barycentric positions and velocities of 5001 VCs at 250 au from the Sun are given here (data format), i.e. after leaving the planetary zone.