Is Sirius B actually an exoplanet? The search for a close neighbour
The planet "Sirius B", lets call it Nabo from Norwegian for neighbour, was first observed in 1962 and reported by Bond to be so faint that it appeared "only feebly self-luminous", and, they were assuming that it was a star and therefore ought to be self-luminous to begin with. The a priori that Sirius had an "invisible companion" was already out there, proposed by Friedrich Bessel 18 years earlier in 1844, in a failure to wrap his head around that it was his own sun that was the companion star. The light spectrum of Nabo was photographed by Adams in 1915, and found to be "remarkable similar" to that of Sirius ("A"), and, as Nabo is reflecting light from Sirius, the star it orbits, that would be expected.
Synapses
Adams, W.S., 1915. The Spectrum of the Companion of Sirius. The Astronomical Society of the Pacific. Volume 27, Number 161.
Bessel, G. R. (1845). Ueber Veränderlichkeit der eigenen Bewegungen der Fixsterne. Astronomische Nachrichten, 22(10), 145–160. https://doi.org/10.1002/asna.18450221002
Bond, G.P., 1862. On the Companion of Sirius. Astronomische Nachrichten, 57:131–134.
https://en.wikipedia.org/wiki/List_of_directly_imaged_exoplanets
https://www.space.com/31497-exoplanets-direct-imaging-next-big-thing.html
a lot to be discovered yet
I think I solved it finally, what F.W. Bessel observed in the 1830s was just Sirius orbiting the center of gravity of its planetary system,
https://steemit.com/sirius/@johan-nygren/on-variations-in-proper-motion-from-the-sirius-system-barycenter