Iota Aquarii

Iota Aquarii
Location of ι Aquarii (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Aquarius
Right ascension 22h 06m 26.22742s[1]
Declination –13° 52′ 10.8615″[1]
Apparent magnitude (V) 4.279[2]
Characteristics
Spectral type B8 V[3]
U−B color index –0.288[2]
B−V color index –0.062[2]
Variable type constant[4]
Astrometry
Radial velocity (Rv)–10.0[5] km/s
Proper motion (μ) RA: +36.89[1] mas/yr
Dec.: –58.99[1] mas/yr
Parallax (π)18.62 ± 0.22 mas[1]
Distance175 ± 2 ly
(53.7 ± 0.6 pc)
Absolute magnitude (MV)+0.64[6]
Details[7]
A
Mass3.20+0.20
−0.16 M☉
Radius2.7[8] R☉
Luminosity74[6] L☉
Surface gravity (log g)4.09±0.08[9] cgs
Temperature11,284±284[8] K
Metallicity [Fe/H]−0.08±0.12[9] dex
Rotational velocity (v sin i)135[10] km/s
Age124+37
−62 Myr
B
Mass1.00±0.03 M☉
Temperature5,710±112 K
Metallicity [Fe/H]−0.5 dex
Rotational velocity (v sin i)20 km/s
Other designations
ι Aqr, 33 Aquarii, BD–14 6209, FK5 828, HD 209819, HIP 109139, HR 8418, SAO 164861[11]
Database references
SIMBADdata

Iota Aquarii, Latinised from ι Aquarii, is the Bayer designation for a binary star[7] system in the equatorial constellation of Aquarius. It is visible to the naked eye with an apparent magnitude of +4.279.[2] Based upon parallax measurements made during the Hipparcos mission, the distance to this star is around 175 light-years (54 parsecs).[2] The system is drifting closer to the Sun with a radial velocity of −10 km/s.[5]

The binary nature of this system was reported in 2009 following a radial velocity survey using the HARPS instrument.[4] A 2010 infrared search for companions around this star was unsuccessful.[12] 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.[7]

The spectrum of the primary, component A, fits a stellar classification of B8 V,[3] showing that this is a B-type main-sequence star. It is roughly 124[7] million years old and is spinning rapidly with a projected rotational velocity of 135 km/s.[10] The star has 3.2[7] times the mass of the Sun and 2.7[8] times the Sun's radius. It is radiating 74[6] times the luminosity of the Sun from its photosphere at an effective temperature of ~11,284 km/s.[8] The secondary, component B, has a spectrum of a solar-mass star.[7] The system is a source for X-ray emission.[13]

  1. ^ a b c d e Cite error: The named reference aaa474_2_653 was invoked but never defined (see the help page).
  2. ^ a b c d e Cite error: The named reference aass61_387 was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference houk1978 was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference Lagrange_et_al_2009 was invoked but never defined (see the help page).
  5. ^ a b Cite error: The named reference scfs was invoked but never defined (see the help page).
  6. ^ a b c Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
  7. ^ a b c d e f Cite error: The named reference Gullikson_et_al_2016 was invoked but never defined (see the help page).
  8. ^ a b c d Cite error: The named reference mnras189_601 was invoked but never defined (see the help page).
  9. ^ a b Cite error: The named reference aaa525_A71 was invoked but never defined (see the help page).
  10. ^ a b Cite error: The named reference apj573_1_359 was invoked but never defined (see the help page).
  11. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  12. ^ Cite error: The named reference aaa523_A73 was invoked but never defined (see the help page).
  13. ^ Cite error: The named reference Haakonsen_Rutledge_2009 was invoked but never defined (see the help page).