Chi1 Fornacis

Chi¹ Fornacis, Latinised from χ¹ Fornacis is a solitary white-hued star located in the southern constellation Fornax. It is barely visible to the naked eye with an apparent magnitude of 6.39,^[2] which is near the limit for naked eye visibility. Gaia DR3 parallax measurements imply a distance of 339 light-years^[1] and it is currently drifting away with a heliocentric radial velocity of 19.0 km/s.^[6] At its current distance, Chi¹ Fornacis' brightness is diminished by an interstellar extinction of 0.08 magnitudes^[15] and it has an absolute magnitude of +1.42.^[7]

For other stars with a similar Bayer designation, see χ Fornacis.

χ¹ Fornacis

Location of χ1 Fornacis (circled)
Observation data Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation	Fornax
Right ascension	03h 25m 55.84196s[1]
Declination	−35° 55′ 15.1876″[1]
Apparent magnitude (V)	6.39±0.01[2]
Characteristics
Evolutionary stage	main sequence star[3]
Spectral type	A1 IV[4]
B−V color index	+0.08[5]
Astrometry
Radial velocity (Rv)	19.0±0.5[6] km/s
Proper motion (μ)	RA: +36.770 mas/yr[1] Dec.: −4.641 mas/yr[1]
Parallax (π)	9.6154±0.0266 mas[1]
Distance	339.2 ± 0.9 ly (104.0 ± 0.3 pc)
Absolute magnitude (MV)	+1.42[7]
Details
Mass	2.05±0.08[8] M☉
Radius	2.20±0.11[9] R☉
Luminosity	31.24+3.43 −3.09[3] L☉
Surface gravity (log g)	4.08±0.07[10] cgs
Temperature	8,770+122 −120[3] K
Metallicity [Fe/H]	0.00+0.02 −0.04[8] dex
Rotational velocity (v sin i)	136[11] km/s
Age	5.5±0.5[12] Myr
Other designations
χ1 For, 89 G. Fornacis[13], NSV 1162, CD−36°1290, CPD−36°350, GC 4097, HD 21573, HIP 15987, HR 1042, SAO 194289[14]
Database references
SIMBAD	For data

Chi¹ Fornacis has a stellar classification of A1 IV,^[4] 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,^[16] 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^[8] and 2.20 times the radius of the Sun.^[9] It radiates 31.24 times the luminosity of the Sun from its photosphere at an effective temperature of 8,870 K.^[3] Chi¹ Fornacis has a solar metallicity^[8] and it is estimated to be only 5.5 million years old.^[12] It spins rapidly with a projected rotational velocity of 136 km/s.^[11]

It is the brightest star and titular member in the χ¹ Fornacis cluster, a star cluster around 104 parsecs from Earth.^[17]

χ1 Fornacis cluster

The χ¹ Fornacis cluster, or Alessi 13,^[18] is one of the four star clusters known within 110 parsecs from Earth. ^[17] Despite its closeness, the χ¹ Fornacis cluster has barely been studied. Its age is 40 million years and its distance is 104 parsecs.^[17] The χ¹ Fornacis cluster appears to be closely related to the Tucana–Horologium and Columba associations.^[17] 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.^[17]