Aspects of this topic are discussed in the following places at Britannica.
...stars of about 20 times the Earth’s distance from the Sun. Despite the glare of the bright star, the seventh-magnitude companion is readily seen with a large telescope. This companion star, known as Sirius B, is about as massive as the Sun, though much more condensed, and was the first white dwarf star to be discovered.
...to be recognized was the companion to Sirius. It was originally detected by its gravitational attraction on the larger, brighter star and only later observed visually as a faint object (now called Sirius B), about 10,000 times fainter than Sirius (now called Sirius A) or 500 times fainter than the Sun. Its mass is slightly less than that of the Sun, and its size a little less than that of...
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