Chi1 Fornacis Explained

Chi1 Fornacis, Latinised from χ1 Fornacis is a solitary white-hued star located in the southern constellation Fornax. Its barley visible to the naked eye with an apparent magnitude of 6.39, which is near the limit for naked eye visibility. Gaia DR3 parallax measurements imply a distance of 339 light-years and it is currently drifitng away with a heliocentric radial velocity of . At its current distance, Chi1 Fornacis' brightness is diminshed by an interstellar extinction of 0.08 magnitudes and it has an absolute magnitude of +1.42.

Chi1 Fornacis has a stellar classification of A1 IV, indicating that it is a slightly evolved A-type star that is ceasing hydrogen fusion at its core. Alternatively, it has been given a class of A1 Vbn, indicating that it is instead a slightly less luminous A-type main-sequence star with broad or nebulous absorption lines due to rapid rotation. It has 2.05 times the mass of the Sun and 2.20 times the radius of the Sun. It radiates 31.24 times the luminosity of the Sun from its photosphere at an effective temperature of . Chi1 Fornacis has a solar metallicity and it is estimated to be only 5.5 million years old. It spins rapidly with a projected rotational velocity of .

It is the brightest star and titular member in the χ1 Fornacis cluster, a star cluster around 104 parsecs from Earth.

χ1 Fornacis cluster

The χ1 Fornacis cluster, or Alessi 13, is one of the four star clusters known within 110 parsecs from Earth. Despite its closeness, the χ1 Fornacis cluster has barely been studied. Its age is 40 million years and its distance is 104 parsecs. The χ1 Fornacis cluster appears to be closely related to the Tucana–Horologium and Columba associations. A remarkable, unprecedented aspect of the cluster is the large percentage of M-type stars with warm excess infrared emission due to orbiting dust grains.