Eta Indi
Location of η Indi (circled) | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Indus |
| Right ascension | 20h 44m 02.33404s[1] |
| Declination | −51° 55′ 15.4970″[1] |
| Apparent magnitude (V) | 4.52[2] |
| Characteristics | |
| Evolutionary stage | Main sequence[3] |
| Spectral type | A9IV[4] |
| B−V color index | +0.26[2] |
| Astrometry | |
| Radial velocity (Rv) | −1.6±0.8[5] km/s |
| Proper motion (μ) | RA: +155.80[1] mas/yr Dec.: −53.86[1] mas/yr |
| Parallax (π) | 41.37±0.25 mas[1] |
| Distance | 78.8 ± 0.5 ly (24.2 ± 0.1 pc) |
| Absolute magnitude (MV) | +2.59±0.01[3] |
| Details | |
| Mass | 1.60[6] M☉ |
| Radius | 1.66[3] R☉ |
| Luminosity | 7.60[7] L☉ |
| Temperature | 7,500[3] K |
| Rotation | 0.20–1.12[3] days |
| Rotational velocity (v sin i) | 75[3] km/s |
| Age | 100±50[8] Myr |
| Other designations | |
| η Ind, CPD−52°11752, FK5 776, HD 197157, HIP 102333, HR 7920, SAO 246709[2] | |
| Database references | |
| SIMBAD | data |
Eta Indi, Latinised from η Indi, is a single, white-hued star in the southern constellation Indus. It is a faint star but visible to the naked eye with an apparent visual magnitude of 4.52.[2]
Measurements with the Hipparcos spacecraft showed the star, which is single,[9] appears to move against the deep sky backdrop by a mean biannual parallax shift of around 41.37 mas,[1] which equates to 79 light-years' distance. Its radial vector to our system's own trajectory (radial velocity) shows it to be in a phase of a narrowing of the gap, at a rounded −2 km/s, net.[5] η Indi appears to be a member of the Octans association, a group of 62 stars that are around 30−50 million years old and have common motion.[10]
The spectrum of this star matches a stellar classification of A9 IV[4] which would suggest it is an evolving subgiant star of type A, but the absolute magnitude of the star argues for a "V" luminosity class and therefore it is likely on the main sequence.[3] The star is estimated 1.6 M☉ (masses of the Sun),[6] and 2.27 R☉ (its radius).[8] It is shines with 7.60[7] times the Sun's luminosity, which is radiated from its photosphere at an effective temperature of 7,694 K.[6] The star is spinning with a projected rotational velocity of 75 km/s.[3] It is very likely to be a hybrid Delta Scuti/Gamma Doradus variable.[3]
References
[edit | edit source]- ^ a b c d e f Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value). Vizier catalog entry
- ^ a b c d Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- ^ a b c d e f g h i Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- ^ a b Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- ^ a b Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- ^ a b c Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value). Vizier catalog entry
- ^ a b Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value). Vizier catalog entry
- ^ a b Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
