C/1891 T1 (Barnard)
Parabolic comet
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Barnard's Comet, formally designated as C/1891 T1, is a faint non-periodic comet that was observed through telescopes in late 1891. It is one of 16 comets discovered by Edward Emerson Barnard.
| Discovery[1] | |
|---|---|
| Discovered by | Edward E. Barnard |
| Discovery site | Lick Observatory |
| Discovery date | 3 October 1891 |
| Designations | |
| 1891 IV, 1891e[2] | |
| Orbital characteristics[3] | |
| Epoch | 14 November 1891 (JD 2412050.5427) |
| Observation arc | 65 days |
| Number of observations | 41 |
| Perihelion | 0.971 AU |
| Eccentricity | ~1.000 |
| Orbital period | ~54,400 years[4] |
| Inclination | 77.988° |
| 219.528° | |
| Argument of periapsis | 269.567° |
| Last perihelion | 14 November 1891 |
| Physical characteristics[5] | |
| 9.4 (1891 apparition) | |
Orbit
William Wallace Campbell published the first orbital calculations for the comet, using positions obtained from the Lick Observatory between 3 and 5 October 1891.[6] These were further refined by Campbell himself a year later,[7] alongside other astronomers, Elizabeth B. Davis,[8] Adolf Berberich and R. Froebe, where they determined a perihelion date of 13 November 1891.
In 1894, while also working out the ephemerides for 489P/Denning (1894 I), John Russell Hind improved C/1891 T1's orbit by using positions obtained from the Cordoba Observatory between 20 October and 4 December 1891, resulting in a revised perihelion date of 14 November 1891.[9] Henry A. Peck provided the comet's definitive orbit in 1903, where he determined two different trajectories, an elliptical orbit with an orbital period of approximately 54,400 years, and a parabolic trajectory. However, the residuals for the elliptical orbit solution were rather large, thus the latter parabolic trajectory is favored for the comet.[4]