Astronomy:Iota Antliae
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| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Antlia[1] |
| Right ascension | 10h 56m 43.051s[2] |
| Declination | −37° 08′ 15.96″[2] |
| Apparent magnitude (V) | +4.60[3] |
| Characteristics | |
| Evolutionary stage | horizontal branch[4] |
| Spectral type | K1 III[5] |
| U−B color index | +0.84[3] |
| B−V color index | +1.03[3] |
| Astrometry | |
| Radial velocity (Rv) | 2.04±0.12[2] km/s |
| Proper motion (μ) | RA: +74.069[2] mas/yr Dec.: −124.443[2] mas/yr |
| Parallax (π) | 15.7132 ± 0.1156[2] mas |
| Distance | 208 ± 2 ly (63.6 ± 0.5 pc) |
| Absolute magnitude (MV) | +0.65[6] |
| Details[6] | |
| Mass | 1.74±0.196 M☉ |
| Radius | 10.71±0.23 R☉ |
| Luminosity | 58.01±1.64 L☉ |
| Surface gravity (log g) | 2.6±0.09 cgs |
| Temperature | 4,867±38 K |
| Metallicity [Fe/H] | −0.02±0.03 dex |
| Age | 3.32[7] Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
Iota Antliae is a single,[9] orange-hued star in the southern constellation of Antlia. Its identifier is a Bayer designation that is Latinized from ι Antliae, and abbreviated Iot Ant or ι Ant, respectively. It has an apparent visual magnitude of +4.60,[3] making it a faint naked eye star. From parallax measurements, the distance to this star can be estimated as 208 ± 2 light-years (63.64 ± 0.5 parsecs). It is drifting further away with a radial velocity of 2 km/s.[2]
The spectrum of Iota Antliae matches a stellar classification of K1 III,[5] indicating that this is an evolved star that is now in its giant phase. Having exhausted the supply of hydrogen at its core, the star has expanded and it now spans 11 times the radius of the Sun.[6] It is a red clump giant, indicating it is on the horizontal branch and is generating energy through helium fusion.[4] The star is 3.32[7] billion years old with 1.55[7] times the Sun's mass. It is radiating 58[6] times the luminosity of the Sun from its swollen photosphere at an effective temperature of 4,892 K.[10]
Planetary system
Two super-Jovian planets around Iota Antilae (or HD 94890), detected by the radial velocity method, were reported in 2025.[6]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | ≥2.13+0.16 −0.17 MJ |
2.07±0.01 | 824.61+5.02 −4.80 |
0.22+0.08 −0.09 |
— | — |
| c | ≥8.91+0.24 −0.25 MJ |
4.33±0.02 | 2492.19+14.72 −13.94 |
0.05±0.03 | — | — |
References
- ↑ Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters 38 (5): 331, doi:10.1134/S1063773712050015, Bibcode: 2012AstL...38..331A.
- ↑ 2.0 2.1 2.2 2.3 2.4 2.5 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940 Gaia DR3 record for this source at VizieR.
- ↑ 3.0 3.1 3.2 3.3 Johnson, H. L. et al. (1966), "UBVRIJKL photometry of the bright stars", Communications of the Lunar and Planetary Laboratory 4 (99): 99, Bibcode: 1966CoLPL...4...99J.
- ↑ 4.0 4.1 Kubiak, M. et al. (June 2002), "Metal Abundance of Red Clump Stars in Baade's Window", Acta Astronomica 52: 159–175, Bibcode: 2002AcA....52..159K.
- ↑ 5.0 5.1 Houk, Nancy (1979), Michigan catalogue of two-dimensional spectral types for the HD stars, 3, Ann Arbor, Michigan: Dept. of Astronomy, University of Michigan, Bibcode: 1982mcts.book.....H.
- ↑ 6.0 6.1 6.2 6.3 6.4 6.5 Fontanet, E. et al. (May 2025). "CORALIE radial-velocity search for companions around evolved stars (CASCADES) IV: New planetary systems around HD 87816, HD 94890, and HD 102888 and an update on HD 121056". Astronomy & Astrophysics.
- ↑ 7.0 7.1 7.2 Luck, R. Earle (2015), "Abundances in the Local Region. I. G and K Giants", Astronomical Journal 150 (3): 88, doi:10.1088/0004-6256/150/3/88, Bibcode: 2015AJ....150...88L.
- ↑ "iot Ant -- Star". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=iot+Ant+--+Star.
- ↑ Eggleton, P. P.; Tokovinin, A. A. (2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society 389 (2): 869, doi:10.1111/j.1365-2966.2008.13596.x, Bibcode: 2008MNRAS.389..869E.
- ↑ Alves, S. et al. (April 2015), "Determination of the spectroscopic stellar parameters for 257 field giant stars", Monthly Notices of the Royal Astronomical Society 448 (3): 2749–2765, doi:10.1093/mnras/stv189, Bibcode: 2015MNRAS.448.2749A.
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