Iota Pegasi

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Iota Pegasi
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Pegasus
Right ascension 22h 07m 00.666s[1]
Declination 25° 20′ 42.40″[1]
Apparent magnitude (V) 3.84/6.68[2]
Spectral type F5V + G8V[3]
Proper motion (μ) RA: 296.53 ± 0.59[1] mas/yr
Dec.: 27.29 ± 0.58[1] mas/yr
Parallax (π) 85.28 ± 0.63[1] mas
Distance 38.2 ± 0.3 ly
(11.73 ± 0.09 pc)
Absolute magnitude (MV) 3.49/6.33[2]
Companion Iota Pegasi B
Period (P) 10.2130253(16) d
Semi-major axis (a) 10.329(16) mas
Eccentricity (e) 0.001764(63)
Inclination (i) 95.83(12)°
Longitude of the node (Ω) 176.262(75)°
Periastron epoch (T) 52997.378(52)
Argument of periastron (ω)
Semi-amplitude (K1)
48.4757(39) km/s
Semi-amplitude (K2)
77.777(16) km/s
ι Peg A
Mass 1.33[2] M
Radius 1.526 ± 0.068[4] R
Surface gravity (log g) 4.26[2] cgs
Temperature 6,580[2] K
Age 4−663[3] Myr
ι Peg B
Mass 0.82[2] M
Radius 0.73[2] R
Surface gravity (log g) 4.62[2] cgs
Temperature 5,060[2] K
Other designations
24 Pegasi, BD+24° 4533, FK5 831, HD 210027, HIP 109176, HR 8430, SAO 90238.[5]
Database references

Iota Pegasi (ι Peg, ι Pegasi) is a star located within the constellation Pegasus. It is about 38 light-years from Earth.[1] It is a spectroscopic binary system.[3]

Iota Pegasi A is a yellowish-white star somewhat brighter than the sun. It and the dimmer Iota Pegasi B orbit each other with a period of about 10 days. In about four billion years from now, component A will evolve off the main sequence into a giant. In the process it will overflow its Roche lobe and begin to transfer mass onto the secondary. This may cause the secondary to acquire enough mass to become the primary component. After both stars have passed through the giant star stage, the end result will be a pair of co-orbiting white dwarfs in about eight billion years.[2]


  1. ^ a b c d e f van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653–664. arXiv:0708.1752Freely accessible. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357.  Vizier catalog entry
  2. ^ a b c d e f g h i j Fuhrmann, Klaus (February 2008), "Nearby stars of the Galactic disc and halo - IV", Monthly Notices of the Royal Astronomical Society, 384 (1): 173–224, Bibcode:2008MNRAS.384..173F, doi:10.1111/j.1365-2966.2007.12671.x 
  3. ^ a b c d Konacki, Maciej; et al. (2010). "High-precision Orbital and Physical Parameters of Double-lined Spectroscopic Binary Stars—HD78418, HD123999, HD160922, HD200077, and HD210027". The Astrophysical Journal. 719 (2): 1293–1314. arXiv:0910.4482Freely accessible. Bibcode:2010ApJ...719.1293K. doi:10.1088/0004-637X/719/2/1293. 
  4. ^ van Belle, Gerard T.; von Braun, Kaspar (2009). "Directly Determined Linear Radii and Effective Temperatures of Exoplanet Host Stars". The Astrophysical Journal. 694 (2): 1085–1098. arXiv:0901.1206Freely accessible. Bibcode:2009ApJ...694.1085V. doi:10.1088/0004-637X/694/2/1085. 
  5. ^ "iot Peg -- Spectroscopic binary", SIMBAD Astronomical Object Database, Centre de Données astronomiques de Strasbourg, retrieved 2016-06-15 

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