Editing Hamal (section)

==Properties==
The [[stellar spectrum|spectrum]] of this star matches a [[stellar classification]] of {{nowrap|K2 III Ca-1}}, with the [[luminosity class]] of III indicating that it is an [[stellar evolution|evolved]] [[giant star]] that has exhausted the supply of hydrogen at its core and is now on the [[red-giant branch]].<ref name=mnras340_3_763/> The 'Ca-1' portion of the classification indicates that it shows weaker than normal [[absorption line|lines]] of [[calcium]] in its spectrum. Since 1943, the spectrum of this star has served as one of the stable anchor points by which other stars are classified.<ref name=baas25_1319/> It is estimated to have 65% more mass than the Sun,<ref name="gray2019"/> while [[Astronomical interferometer|interferometric]] measurements using the [[Navy Precision Optical Interferometer]] show it to be 15 times larger in diameter.<ref name="npoi"/> Despite its enlarged girth, this star is still spinning with a slightly faster equatorial [[azimuth]]al velocity than the Sun, having a [[projected rotational velocity]] of 3.44&nbsp;km s<sup>−1</sup>.<ref name=aaa529_A134/>

Hamal is radiating about 91<ref name=aaa526_A100/> times the [[Sun's luminosity]] from its [[stellar atmosphere|outer envelope]] at an [[effective temperature]] of {{Val|4411|fmt=commas|ul=K}}.<ref name="gray2019"/> This is cooler than the surface of the Sun, giving it the orange-hued glow of a [[K-type star]]. It is suspected to be slightly [[variable star|variable]], with an amplitude of 0.06 magnitude.<ref name=nsv1/> The abundance of elements other than hydrogen and helium, what astronomers term the star's [[metallicity]], is only around 60% that in the Sun.<ref name=aaa526_A100/>{{efn|name=metal_fe|1 = The abundance is estimated by taking [Fe/H] to the power of ten:{{indent|10}}10<sup>[Fe/H]</sup> = 10<sup>−0.214</sup> = 0.61}} The star displays low amplitude [[Stellar pulsation|pulsations]] with periods of 0.571 and 0.190&nbsp;days.<ref name=Kim_et_al_2006/>