Editing Procyon (section)

===Procyon B===
[[File:Procyonorbitillustration.jpg|thumb|left|Orbit of Procyon B seen from above its plane]]
Like Sirius B, Procyon B is a [[white dwarf]] that was inferred from [[astrometry|astrometric]] data long before it was observed. Its existence had been postulated by German astronomer [[Friedrich Bessel]] as early as 1844, and, although its orbital elements had been calculated by his countryman [[Arthur Auwers]] in 1862 as part of his thesis,<ref name=auwers/> Procyon&nbsp;B was not visually confirmed until 1896 when [[John Martin Schaeberle]] observed it at the predicted position using the 36-inch refractor at [[Lick Observatory]].<ref name=burnham78/> It is more difficult to observe from Earth than Sirius&nbsp;B, due to a greater [[apparent magnitude]] difference and smaller angular separation from its primary.<ref name=Kaler2011/>

At {{Solar mass|0.6|link=y}}, Procyon&nbsp;B is considerably less massive than Sirius&nbsp;B; however, the peculiarities of [[degenerate matter]] ensure that it is larger than its more famous neighbor, with an estimated radius of 8,600&nbsp;km, versus 5,800&nbsp;km for Sirius&nbsp;B.<ref name="Provencal2002"/><ref name=apj497/> The radius agrees with white dwarf models that assume a carbon core.<ref name="Provencal2002"/> It has a [[stellar classification]] of DQZ,<ref name=Provencal2002/> having a helium-dominated atmosphere with traces of heavy elements. For reasons that remain unclear, the mass of Procyon&nbsp;B is unusually low for a white dwarf star of its type.<ref name=Liebert2013/> With a surface temperature of {{val|fmt=commas|7740|ul=K}}, it is also much cooler than Sirius&nbsp;B; this is a testament to its lesser mass and greater age. The mass of the progenitor star for Procyon B was about {{val|2.59|+0.22|-0.18|u=solar mass}} and it came to the end of its life some {{val|1.19|0.11}}&nbsp;billion years ago, after a main-sequence lifetime of {{val|680|170}}&nbsp;million years.<ref name=Liebert2013/>