Episode 2 of 2
Deduction of Sirius's Companion
- When
- 10 August 1844
- Where
- Königsberg Observatory
Bessel deduced an unseen companion for Sirius from proper motion changes, announced in a letter dated 10 August 1844.
Using a new meridian circle, Bessel noticed deviations in Sirius's motion. He concluded these were caused by gravitational attraction from an unseen companion. This announcement was the first correct claim of an unobserved companion by positional measurement.
Sources
- Sirius Wikipedia, revision of 2026-09-25
- Friedrich Wilhelm Bessel Wikipedia, revision of 2026-08-29
Machine-drafted from the cited Wikipedia passages and checked by a reviewing model, not by a human editor. Every passage cites the revision it was written from; dates and places follow those passages.