X Trianguli Australis is a star in the southern constellation Triangulum Australe. It is a red-hued carbon star approximately 920 light years (280 parsecs) from Earth, though this could vary by up to 200 light years.[1] It is a semi-regular variable star with two periods of around 385 and 455 days, and is of spectral type C5.5(Nb). It ranges from magnitudes 5.03 to 6.05.[2] Its designation is from the variable star designation developed by German astronomer Friedrich Wilhelm Argelander.
It is a cool star, with estimates of its surface temperature ranging from 2,200 to 2,700 Kelvin.[1] A giant star, its diameter is 400 times that of the sun, and if placed at the center of the Solar System would stretch out to 30% further than Mars' orbit. Its absolute magnitude is −2.0.[1]