C/1855 L1 (Donati)
Long-period comet discovered by Giovanni Battista Donati in 1855.
C/1855 L1 (Donati) is a long-period comet discovered by Italian astronomer Giovanni Battista Donati on 3 June 1855. It was the second comet discovered in 1855 and the first of five comets found by Donati.
Quick Facts
- Discoverer
- Giovanni B. Donati
- Discovery Date
- 3 June 1855
- Discovery Site
- Florence, Italy
- Designations
- 1855 IIICQ1
- Orbit Ref
- jpl
- Epoch
- 17 May 1855 (JD 2398720.5)
- Observation Arc
- 14 days
- Obs
- 49
- Perihelion
- 0.5676 AU
- Aphelion
- 79.259 AU
- Semimajor
- 39.913 AU
- Period
- 252 years
Facts from the source article.
Lore & Background
The comet was discovered by Giovanni Battista Donati on the night of 3 June 1855, who described it as lacking a nucleus and tail, and seemingly fainter than Messier 13. Independent observations were made by Charles Dien, Jr. and Wilhelm Klinkerfues the following day. The comet was already on its outbound flight upon discovery, and observers noted it had faded significantly by 14 June. It was last observed from Germany on 30 June 1855.
Initial orbital calculations by Karl Christian Bruhns and Donati yielded an orbital period of 493 years, with Donati concluding its similarity to C/1362 E1 and suggesting a possible return to the inner Solar System. However, in 1916, George van Biesbroeck revised the orbital period to 252 years, accounting for gravitational perturbations by Venus and Saturn, and concluded it is unlikely that the comets of 1362 and 1855 were the same object.
Reader's Guide
C/1855 L1 (Donati) holds significance as the first of five comets discovered by Giovanni Battista Donati, a notable Italian astronomer. Its discovery on 3 June 1855 marked it as the second comet found that year. The comet's orbital history involves a notable revision: initial calculations by Karl Christian Bruhns and Donati suggested a 493-year period and a possible link to the comet C/1362 E1, but George van Biesbroeck's 1916 analysis, incorporating gravitational perturbations from Venus and Saturn, reduced the period to approximately 252 years and dismissed the connection to the earlier comet. This revision highlights the importance of refined orbital mechanics in understanding long-period comets. The comet was already leaving the inner Solar System when discovered, fading rapidly and last observed on 30 June 1855, providing a brief observational window that nonetheless contributed to early cometary science.
Did You Know?
- The comet was discovered without a nucleus or tail, appearing fainter than Messier 13.
- It was independently observed by Charles Dien, Jr. and Wilhelm Klinkerfues on 4 June 1855.
- Initial orbital calculations gave a period of 493 years, later revised to 252 years by George van Biesbroeck in 1916.
- The comet was already on its outbound flight when discovered and faded significantly by 14 June 1855.
Frequently Asked Questions
Who discovered C/1855 L1 (Donati)?
Italian astronomer Giovanni Battista Donati identified this comet on 3 June 1855. It was the second comet spotted that year and the first of five comets Donati would go on to discover.
What is the orbital period of C/1855 L1 (Donati)?
Donati and Karl Christian Bruhns originally calculated the period at roughly 493 years. A later revision in 1916 corrected this to approximately 252 years, classifying it firmly as a long-period visitor.
Why is C/1855 L1 (Donati) considered notable among 19th-century comets?
Its bright appearance in mid-1855 made it a public spectacle and cemented Donati's reputation as a prolific comet hunter. With an orbital period near 252 years, it is an exceedingly rare guest in the inner solar system.
When was C/1855 L1 (Donati) last observed by astronomers?
The final recorded sighting came on 30 June 1855 from an observatory in Germany. After that brief window the comet faded beyond detection as it headed back out on its centuries-long orbit.
What does the "C" in the designation C/1855 L1 indicate?
The "C" prefix marks the object as a non-periodic (long-period) comet, distinguishing it from short-period comets that carry a "P" designation. The "1855 L1" portion simply encodes the year and discovery sequence under the older naming convention.
More in Named Comets, Part 3 1-24
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