Great Southern Comet of 1887
 Observations of the tail of C/1887 B1, Knowledge, Nov. 1887 | |
| Discovery | |
|---|---|
| Discovered by | J. M. Thome |
| Discovery date | January 19, 1887 |
| Designations | |
| 1887 I; 1887a; Great Southern Comet of 1887; the "Headless Wonder"; Thome's Comet | |
| Orbital characteristics | |
| Observation arc | 8 days (very short arc)[1] |
| Number of observations | 15 |
| Orbit type | Kreutz sungrazer |
| Perihelion | 0.00483 AU (723 thousand km)[1][2] |
| Eccentricity | 1.0 (assumed)[1] |
| Max. orbital speed | 606.1 km/s @ perihelion[3] |
| Inclination | 144.383° |
| Last perihelion | January 11, 1877 |
The Great Southern Comet of 1887, or C/1887 B1 using its
A curious feature of the comet was that few, if any observations were made of a cometary head or
Discovery
The comet was officially discovered by astronomer
Observations
The comet reached first magnitude,[7] and was widely observed by astronomers in the Southern Hemisphere for the remainder of January. On the 22nd Finlay described it as a "pale narrow ribbon of light, quite straight" of about 35 degrees in length, though no cometary head could be distinguished.[8] On the 23rd, Thome recorded a tail length of over 40 degrees, but like other observers stated he could not find a nucleus. On January 27, C. Todd recorded seeing the comet's head as a "diffused nebulous mass", but noted a break between the head and the tail (possibly representing what is referred to as a tail disconnection event).
Following the publication of an ephemeris by S. C. Chandler, which suggested the comet could be located 20° from Rigel by the end of February, astronomers in the United States eagerly waited for it to move far enough into northern skies to be visible.[9] However, the comet faded extremely rapidly, and never became visible from northern latitudes. It was last observed by John Tebbutt from New South Wales on January 30, a relatively short period of observation overall for a comet.
Analysis
The first, speculative, orbit was calculated by
Sekanina was subsequently to speculate that the unusual appearance of the comet was due to a "tail formation event", an outburst of cometary dust, about 6 hours after perihelion.[11] This event and the rapidly fading brightness, Sekanina argued, showed that C/1887 B1, along with C/1945 X1 (du Toit), represented a class of comets in between the "great" sungrazers (such as the Great Comet of 1882) and the many smaller objects discovered by the Solar and Heliospheric Observatory.
| Perihelion (Sun approach) |
Earth distance (AU) |
Sun centerpoint distance (AU) |
Velocity relative to Earth (km/s) |
Velocity relative to Sun (km/s) |
Solar elongation |
|---|---|---|---|---|---|
| 11 January 1887 ≈22:33 | 0.987 LD ) |
0.00483 AU (723 thousand km; 449 thousand mi; 1.88 LD) | 576.7 | 606.1 | 0.16° |
References
- ^ a b c "JPL Small-Body Database: C/1887 B1 (Great southern comet)". Jet Propulsion Laboratory.
- ^ Orbital elements given by Sekanina, QJRAS, 19 (1978), 52-3
- ^ a b c "Horizons Batch for C/1887 B1 on 11 January 1877" (Perihelion occurs when rdot flips from negative to positive). JPL Horizons. Retrieved 2023-09-03.
- ^ Bortle, J. The Bright Comet Chronicles, International Comet Quarterly, 1998
- ^ a b Kronk, G. W. Cometography, v2, CUP, 2003, p.588
- ^ "Horizons Batch for C/1887 B1 on 1886-Dec-22" (closest Earth approach occurs when deldot flips from negative to positive). JPL Horizons. Retrieved 2023-09-03.
- ^ Milani, De Martino & Cellino (eds) Asteroids, comets, meteors 1993: proceedings of the 160th Symposium of the International Astronomical Union, held in Belgirate, Italy, June 14–18, 1993, Springer, 1994, p.8
- ^ Kronk, p.589
- ^ "Lost Tramp of the Skies - The Great Southern Comet Disappears", New York Times, February 27, 1887
- ^ Kronk, p.591
- ^ Sekanina, Z. Statistical Investigation and Modeling of Sungrazing Comets Discovered with the Solar and Heliospheric Observatory, The Astrophysical Journal, 566:577-598, 2002 February 10
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