Chi1 Fornacis
Star in the constellation Fornax
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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]
 | |
| Observation data Epoch J2000.0 Equinox 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]