Α_Sextantis
Alpha Sextantis
Star in the constellation Sextans
Alpha Sextantis (α Sex, α Sextantis) is the brightest star in the equatorial constellation of Sextans.[11] It is visible to the naked eye on a dark night with an apparent visual magnitude of 4.49.[2] The distance to this star, as determined from parallax measurements,[1] is around 280 light years. This is considered an informal "equator star", as it lies less than a quarter of a degree south of the celestial equator. In 1900, it was 7 minutes of arc north of the equator. As a result of a shift in the Earth's axial tilt, it crossed over to the southern hemisphere in December 1923.[12]
The variability of Alpha Sextantis was discovered by Aven Magded Hamadamen and included in the International Variable Star Index.[13] The star undergoes pulsations with a period of 9.1 hours.[6]
This is an evolved A-type giant star with a stellar classification of A0 III.[3] It has around 2.5[6] times the mass of the Sun and three[6] times the Sun's radius. The abundance of elements is similar to that in the Sun.[7] It radiates 90 times the solar luminosity[6] from its outer atmosphere at an effective temperature of 9,984 K.[8] Alpha Sextantis is nearing the end of its life as a main-sequence star; it is around 385[6] million years old with a projected rotational velocity of 21 km/s.[9]