Astronomy:Iota Apodis
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| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Apus |
| Right ascension | 17h 22m 05.876s[1] |
| Declination | −70° 07′ 23.54″[1] |
| Apparent magnitude (V) | 5.41[2] (5.90/6.46)[3] |
| Characteristics | |
| Spectral type | B9 V + B9.5 V[3] |
| U−B color index | −0.23[2] |
| B−V color index | −0.04[2] |
| Astrometry | |
| Radial velocity (Rv) | −4.3[4] km/s |
| Proper motion (μ) | RA: −1.881[1] mas/yr Dec.: −11.363[1] mas/yr |
| Parallax (π) | 3.1948 ± 0.1853[1] mas |
| Distance | 1,020 ± 60 ly (310 ± 20 pc) |
| Orbit[5] | |
| Period (P) | 59.32±3.0 yr |
| Semi-major axis (a) | 0.115±0.005″ |
| Eccentricity (e) | 0.172±0.050 |
| Inclination (i) | 69.4±3.0° |
| Longitude of the node (Ω) | 119.6±4.0° |
| Argument of periastron (ω) (secondary) | 270.5±7.0° |
| Details | |
| ι Aps A | |
| Mass | 3.89±1.02[5] M☉ |
| ι Aps B | |
| Mass | 3.45±0.90[5] M☉ |
| Other designations | |
| Database references | |
| SIMBAD | data |
Iota Apodis is a binary star[3] system in the southern circumpolar constellation of Apus. Its identifier is a Bayer designation that is Latinized from ι Apodis, and abbreviated Iot Aps or ι Aps, respectively. This system is a faint target at an apparent visual magnitude of 5.41,[2] but still visible to the naked eye from suitably dark skies. The distance to this star can be gauged from parallax measurements, yielding an estimate of 1,020 light-years (310 parsecs) with a 6% margin of error.[1] The system is drifting closer with a heliocentric radial velocity of −4.3 km/s.[4]
The dual nature of this system was announced by W. S. Finsen in 1960, who reported an angular separation of 0.104 arcseconds.[7] Their orbit has an angular separation of 0.091 arcseconds[3] with an estimated orbital period of 59.32 years and an eccentricity (ovalness) of 0.17.[5] Both stars are B-type main sequence stars, which indicates they shine with a blue-white hue.[8] The brighter component has a stellar classification of B9 V and an apparent magnitude 5.90, while the second member is a B9.5 V star with a magnitude of 6.46. They are about 3.89 and 3.45 times as massive as the Sun, respectively.[5]
Naming
In Chinese caused by adaptation of the European southern hemisphere constellations into the Chinese system, 異雀 (Yì Què), meaning Exotic Bird, refers to an asterism consisting of ι Apodis, ζ Apodis, β Apodis, γ Apodis, δ Octantis, δ1 Apodis, η Apodis, α Apodis and ε Apodis. Consequently, ι Apodis itself is known as 異雀二 (Yì Què èr, English: the Second Star of Exotic Bird.)[9]
References
- ↑ 1.0 1.1 1.2 1.3 1.4 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.
- ↑ 2.0 2.1 2.2 2.3 Nicolet, B. (1978), "Photoelectric photometric Catalogue of homogeneous measurements in the UBV System", Astronomy and Astrophysics Supplement Series 34: 1–49, Bibcode: 1978A&AS...34....1N.
- ↑ 3.0 3.1 3.2 3.3 Eggleton, P. P.; Tokovinin, A. A. (September 2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society 389 (2): 869–879, doi:10.1111/j.1365-2966.2008.13596.x, Bibcode: 2008MNRAS.389..869E.
- ↑ 4.0 4.1 Wilson, Ralph Elmer (1953), "General Catalogue of Stellar Radial Velocities", Carnegie Institute Washington D.C. Publication (Washington: Carnegie Institution of Washington), Bibcode: 1953GCRV..C......0W.
- ↑ 5.0 5.1 5.2 5.3 5.4 Docobo, J. A.; Andrade, M. (January 2013), "Dynamical and physical properties of 22 binaries discovered by W. S. Finsen", Monthly Notices of the Royal Astronomical Society 428 (1): 321–339, doi:10.1093/mnras/sts045, Bibcode: 2013MNRAS.428..321D.
- ↑ "* iot Aps". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=%2A+iot+Aps.
- ↑ Finsen, W. S. (1960), "New Double Stars (XVII)", Monthly Notes of the Astronomical Society of Southern Africa 19: 178, Bibcode: 1960MNSSA..19..178F.
- ↑ "The Colour of Stars", Australia Telescope, Outreach and Education (Commonwealth Scientific and Industrial Research Organisation), December 21, 2004, archived from the original on March 18, 2012, https://web.archive.org/web/20120318151427/http://outreach.atnf.csiro.au/education/senior/astrophysics/photometry_colour.html, retrieved 2012-01-16
- ↑ (in Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 29 日
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