Editing Fomalhaut (section)

===Properties===
Fomalhaut is a young star, for many years thought to be only 100 to 300 million years old, with a potential lifespan of a billion years.<ref name="age"/><ref name="lifespan"/> A 2012 study gave a slightly higher age of {{val|440|40|u=million years}}.<ref name="age_mam"/> The surface temperature of the star is around {{convert|8590|K|C|lk=on}}. Fomalhaut's mass is about 1.92 times that of the [[Sun]], its [[luminosity]] is about 16.6 times greater, and its diameter is roughly 1.84 times as large.<ref name="age_mam"/>

Fomalhaut is slightly [[metallicity|metal-deficient]] compared to the Sun, which means it is composed of a smaller percentage of elements other than hydrogen and helium.<ref name="aaa426" /> The metallicity is typically determined by measuring the abundance of iron in the [[photosphere]] relative to the abundance of hydrogen. A 1997 [[spectroscopic]] study measured a value equal to 93% of the Sun's abundance of iron.<ref name=mnras286_3/><ref name=metal group=nb/> A second 1997 study deduced a value of 78%, by assuming Fomalhaut has the same metallicity as the neighboring star [[TW Piscis Austrini]], which has since been argued to be a physical companion.<ref name="age_mam"/><ref name=apj475/> In 2004, a stellar evolutionary model of Fomalhaut yielded a metallicity of 79%.<ref name=aaa426/> Finally, in 2008, a spectroscopic measurement gave a significantly lower value of 46%.<ref name=aaa490_1/>

Fomalhaut has been claimed to be one of approximately 16 stars belonging to the [[Castor Moving Group]]. This is an association of stars which share a common motion through space, and have been claimed to be physically associated. Other members of this group include [[Castor (star)|Castor]] and [[Vega]]. The [[moving group]] has an estimated age of {{val|200|100|u=million years}} and originated from the same location.<ref name="age"/> More recent work has found that purported members of the Castor Moving Group appear to not only have a wide range of ages, but their velocities are too different to have been possibly associated with one another in the distant past.<ref name=Mamajek2013/> Hence, "membership" in this dynamical group has no bearing on the age of the Fomalhaut system.<ref name=Mamajek2013/>