HD 213402
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  | |
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Octans |
| Right ascension | 22h 35m 26.52327s[1] |
| Declination | −78° 46′ 17.7049″[1] |
| Apparent magnitude (V) | 6.14±0.01[2] |
| Characteristics | |
| Evolutionary stage | red giant branch[1] |
| Spectral type | K1 III[3] |
| U−B color index | +1.35[4] |
| B−V color index | +1.38[4] |
| Astrometry | |
| Radial velocity (Rv) | −12.8±0.4[5] km/s |
| Proper motion (μ) | RA: +53.718 mas/yr[1] Dec.: −7.451 mas/yr[1] |
| Parallax (π) | 3.5469±0.0256 mas[1] |
| Distance | 920 ± 7 ly (282 ± 2 pc) |
| Absolute magnitude (MV) | −1.15[6] |
| Details | |
| Mass | 1.17[7] M☉ |
| Radius | 44.5±2.3[8] R☉ |
| Luminosity | 471±8[9] L☉ |
| Surface gravity (log g) | 1.16[10] cgs |
| Temperature | 4,481±122[11] K |
| Metallicity [Fe/H] | −0.07[7] dex |
| Rotational velocity (v sin i) | <1.0[12] km/s |
| Other designations | |
| 73 G. Octantis[13], CPD−79°1206, FK5 3807, GC 31498, HD 213402, HIP 111504, HR 8577, SAO 258049, TIC 273651959[14] | |
| Database references | |
| SIMBAD | data |
HD 213402 (HR 8577; 73 G. Octantis) is a solitary star located in the southern circumpolar constellation Octans. It has an apparent magnitude of 6.14,[2] placing it near the limit for naked eye visibility. The object is located relatively far at a distance of 920 light-years based on Gaia DR3 parallax measurements,[1] but it is drifting closer with a heliocentric radial velocity of −12.8 km/s.[5] At its current distance, HD 213402's brightness is diminished by 0.45 magnitudes due to interstellar extinction[15] and it has an absolute magnitude of −1.15.[6]
HD 213402 has a stellar classification of K1 III,[3] indicating that it is an evolved K-type giant. It has a comparable mass to the Sun[7] but it has expanded to 44.5 times the radius of the Sun.[8] It radiates 471 times the luminosity of the Sun[9] from its enlarged photosphere at an effective temperature of 4,481 K,[11] giving it the typical orange hue of a K-type star. Gaia DR3 stellar evolution models place it on the red giant branch and yield a larger radius of 50.9 R☉ and a higher luminosity of 825 L☉.[1] HD 213402 is slightly metal deficient with an iron abundance of [Fe/H] = −0.07 or 85% of the Sun's abundance.[7] Like many giant stars it rotates slowly, but its projected rotational velocity is too low to be measured accurately.[12]
