Iota Chamaeleontis
Star in the constellation Chamaeleon
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Iota Chamaeleontis is a single[11] star in the southern circumpolar constellation of Chamaeleon. Its name is a Bayer designation that is Latinized from ι Chamaeleontis, and abbreviated Iota Cha or ι Cha. This star is visible to the naked eye as a dim, yellow-white hued point of light, having an apparent magnitude of about 5.3.[2] Based upon parallax measurements,[5] this star is 188.4 light-years (57.8 pc) away from the Sun, but it is drifting closer with a radial velocity of −4 km/s.[5]
 | |
| Observation data Epoch J2000 Equinox ICRS | |
|---|---|
| Constellation | Chamaeleon |
| Right ascension | 09h 24m 09.224s[1] |
| Declination | –80° 47′ 12.758″[1] |
| Apparent magnitude (V) | 5.34[2] |
| Characteristics | |
| Spectral type | F3/5 III/V[3] |
| U−B color index | +0.01[4] |
| B−V color index | +0.454±0.003[2] |
| Astrometry | |
| Radial velocity (Rv) | −3.57±0.66[5] km/s |
| Proper motion (μ) | RA: –138.717 mas/yr[1] Dec.: +134.880 mas/yr[1] |
| Parallax (π) | 17.3133±0.0528 mas[1] |
| Distance | 188.4 ± 0.6 ly (57.8 ± 0.2 pc) |
| Absolute magnitude (MV) | +1.52[2] |
| Details | |
| Mass | 1.88[6] M☉ |
| Radius | 3.4[7] R☉ |
| Luminosity | 19.1[7] L☉ |
| Temperature | 6,514[7] K |
| Metallicity [Fe/H] | −0.04[8] dex |
| Rotational velocity (v sin i) | 129.7[9] km/s |
| Age | 1.2±0.1[2] Gyr |
| Other designations | |
| ι Cha, CD−80°329, FK5 2753, GC 13066, HD 82554, HIP 46107, HR 3795, SAO 258530[10] | |
| Database references | |
| SIMBAD | data |
Spectra of this star taken in different years have been given types of F3IV/V and F5III, leading to a mean published type of F3/5 III/V, with the suspicion that the spectrum is variable. It is an F-type star, likely an evolving subgiant.[12]
Iota Cha has 1.9[6] times the mass of the Sun with 3.4[7] times the Sun's radius. It is 1.2[2] billion years old with a high rate of spin, showing a projected rotational velocity of 130 km/s.[9] This is giving it an oblate shape with an equatorial bulge some 9% larger than the polar radius.[13] The star is radiating 19.1 times the Sun's luminosity from its photosphere at an effective temperature of 6,514 K.[7] An infrared excess suggests a circumstellar disk of dust is orbiting at a distance of 8.3 AU from the star with a mean temperature of 200 K.[14]