Iota Aquarii
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Aquarius |
| Right ascension | 22h 06m 26.227s |
| Declination | −13° 52′ 10.85″ |
| Apparent magnitude (V) | 4.279 |
| Characteristics | |
| Spectral type | B8 V |
| U−B color index | −0.288 |
| B−V color index | −0.062 |
| Variable type | constant |
| Astrometry | |
| Radial velocity (Rv) | −10.0 km/s |
| Proper motion (μ) | RA: +42.210 mas/yr Dec.: −56.566 mas/yr |
| Parallax (π) | 15.4940±0.2103 mas |
| Distance | 211 ± 3 ly (64.5 ± 0.9 pc) |
| Absolute magnitude (MV) | +0.64 |
| Details | |
| A | |
| Mass | 3.20+0.20 −0.16 M☉ |
| Radius | 2.7 R☉ |
| Luminosity | 74 L☉ |
| Surface gravity (log g) | 4.09±0.08 cgs |
| Temperature | 11,284±284 K |
| Metallicity [Fe/H] | −0.08±0.12 dex |
| Rotational velocity (v sin i) | 135 km/s |
| Age | 124+37 −62 Myr |
| B | |
| Mass | 1.00±0.03 M☉ |
| Temperature | 5,710±112 K |
| Metallicity [Fe/H] | −0.5 dex |
| Rotational velocity (v sin i) | 20 km/s |
| Other designations | |
| ι Aquarii, ι Aqr, 33 Aquarii, BD−14 6209, FK5 828, GC 30914, HD 209819, HIP 109139, HR 8418, SAO 164861, PPM 239801 | |
| Database references | |
| SIMBAD | data |
Iota Aquarii is a binary star system in the equatorial constellation of Aquarius. Its identifier is a Bayer designation that is Latinised from ι Aquarii, and abbreviated Iota Aqr or ι Aqr, respectively. This star is visible to the naked eye with an apparent magnitude of +4.279. Based upon parallax measurements, the distance to this star is around 211 light-years (65 parsecs). The system is drifting closer to the Sun with a radial velocity of −10 km/s.
The binary nature of this system was reported in 2009 following a radial velocity survey using the HARPS instrument. A 2010 infrared search for companions around this star was unsuccessful. The presence of a stellar companion was confirmed through direct spectral detection in 2016. The companion shows a significant velocity variation over a 77-day interval, suggesting a short orbital period.
The spectrum of the primary, component A, fits a stellar classification of B8 V, showing that this is a B-type main-sequence star. It is roughly 124 million years old and is spinning rapidly with a projected rotational velocity of 135 km/s. The star has 3.2 times the mass of the Sun and 2.7 times the Sun's radius. It is radiating 74 times the luminosity of the Sun from its photosphere at an effective temperature of ~11,284 K. The secondary, component B, has a spectrum of a solar-mass star. The system is a source for X-ray emission.