Astronomy:Iota Arietis

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Short description: Binary star system in the constellation Aries
ι Arietis
Location of ι Arietis (circled)
Observation data
Equinox J2000.0]] (ICRS)
Constellation Aries
Right ascension  01h 57m 21.058s[1]
Declination +17° 49′ 03.20″[1]
Apparent magnitude (V) 5.117[2]
Characteristics
Evolutionary stage horizontal branch[3]
Spectral type K1p[4] or G8III[5]
U−B color index +0.700[2]
B−V color index +0.921[2]
Astrometry
Radial velocity (Rv)2.21±0.07[6] km/s
Proper motion (μ) RA: +37.138[1] mas/yr
Dec.: −19.983[1] mas/yr
Parallax (π)7.4277 ± 0.2980[1] mas
Distance440 ± 20 ly
(135 ± 5 pc)
Absolute magnitude (MV)−0.4[7]
Orbit[8]
Period (P)1,567.66±0.62 d
Semi-major axis (a)≥ 217 Gm (1.45 astronomical unit|AU)
Eccentricity (e)0.356±0.022
Periastron epoch (T)2420961.1±27.2 JD
Argument of periastron (ω)
(secondary)		94.04±4.72°
Semi-amplitude (K1)
(primary)		10.78±0.31 km/s
Details
Mass3.17+0.08−0.09[3] M☉
Radius20.4+0.7−0.8[3] R☉
Luminosity240+16−20[3] L☉
Surface gravity (log g)2.60[9] cgs
Temperature5,031+6−2[3] K
Metallicity [Fe/H]−0.10[9] dex
Rotational velocity (v sin i)3.33[9] km/s
Other designations
ι Ari, 8 Arietis, BD+17 289, FK5 2132, GC 2347, HD 11909, HIP 9110, HR 563, SAO 92721, PPM 117816[10]
Database references
SIMBADdata

Iota Arietis is a binary star system in the northern constellation of Aries. Its name is a Bayer designation that is Latinized from ι Arietis, and abbreviated Iota Ari or ι Ari. This star has an apparent visual magnitude of 5.117;[2] bright enough to be dimly seen with the naked eye. Parallax measurements yield an estimated distance of approximately 440 light-years (130 parsecs) from Earth.[11] The position of this system near the ecliptic means it is subject to lunar occultation.[12]

The variable radial velocity of this system was announced by W. W. Campbell in 1922. K. C. Gordon published orbital elements for this single-lined spectroscopic binary system in 1946, giving an orbital period of 4.29 years and an eccentricity (ovalness) of 0.36.[8]

For the visible component, in 1952 N. G. Roman found a stellar classification of K1p, where the 'p' indicates some type of peculiarity with the spectrum. Her comments indicated that the "Hydrogen lines and λ 4290 are strong enough to indicate a class II star, but the CN is barely strong enough for class III, and the Sr II is not much stronger than this would require.".[4] E. A. Harlan published a class of K peculiar in 1969, commenting, "Hδ strong, Fe I λ4045 is weak for type".[13] In 1990, K. Sato and S. Kuji gave a class of G8III, suggesting this is an aging G-type giant star and questioning its peculiar status.[5] Bayesian inference of the stellar properties indicates this star is on the horizontal branch.[3] The companion is a suspected white dwarf.[14]

References

  1. ↑ 1.0 1.1 1.2 1.3 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. ↑ 2.0 2.1 2.2 2.3 Jennens, P. A.; Helfer, H. L. (September 1975), "A new photometric metal abundance and luminosity calibration for field G and K giants.", Monthly Notices of the Royal Astronomical Society 172 (3): 667–679, doi:10.1093/mnras/172.3.667, Bibcode: 1975MNRAS.172..667J. 
  3. ↑ 3.0 3.1 3.2 3.3 3.4 3.5 Stock, Stephan et al. (August 2018), "Precise radial velocities of giant stars. X. Bayesian stellar parameters and evolutionary stages for 372 giant stars from the Lick planet search", Astronomy & Astrophysics 616: 15, doi:10.1051/0004-6361/201833111, A33, Bibcode: 2018A&A...616A..33S. 
  4. ↑ 4.0 4.1 Roman, Nancy G. (July 1952), "The Spectra of the Bright Stars of Types F5-K5", Astrophysical Journal 116: 122, doi:10.1086/145598, Bibcode: 1952ApJ...116..122R. 
  5. ↑ 5.0 5.1 Sato, K.; Kuji, S. (1990), "MK classification and photometry of stars used for time and latitude observations at Mizusawa and Washington", Astronomy and Astrophysics Supplement Series 85: 1069, Bibcode: 1990A&AS...85.1069S. 
  6. ↑ Abdurro’uf (April 2022), "The Seventeenth Data Release of the Sloan Digital Sky Surveys: Complete Release of MaNGA, MaStar, and APOGEE-2 Data", The Astrophysical Journal Supplement Series 259 (2): 35, doi:10.3847/1538-4365/ac4414, ISSN 0067-0049, Bibcode: 2022ApJS..259...35A. 
  7. ↑ Helfer, H. L.; Wallerstein, George (August 1968), "Abundances in K-Giant Stars. II. a Survey of Field Stars", Astrophysical Journal Supplement 16: 1, doi:10.1086/190169, Bibcode: 1968ApJS...16....1H. 
  8. ↑ 8.0 8.1 Gordon, Katherine C. (1946), "The Spectroscopic Orbit of ι Arietis", The Astrophysical Journal 103: 16–18, doi:10.1086/144784, Bibcode: 1946ApJ...103...16G. 
  9. ↑ 9.0 9.1 9.2 Hekker, S.; Meléndez, J. (2007), "Precise radial velocities of giant stars. III. Spectroscopic stellar parameters", Astronomy and Astrophysics 475 (3): 1003–1009, doi:10.1051/0004-6361:20078233, Bibcode: 2007A&A...475.1003H. 
  10. ↑ "* iot Ari". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=%2A+iot+Ari. 
  11. ↑ van Leeuwen, F. (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics 474 (2): 653–664, doi:10.1051/0004-6361:20078357, Bibcode: 2007A&A...474..653V. 
  12. ↑ Herr, Richard B. (April 1969), "Identification List of Spectroscopic and Eclipsing Binaries Subject to Occultations by the Moon", Publications of the Astronomical Society of the Pacific 81 (479): 105, doi:10.1086/128748, Bibcode: 1969PASP...81..105H. 
  13. ↑ Harlan, E. A. (September 1969), "MK classifications for F- and G-type stars. I", Astronomical Journal 74: 916, doi:10.1086/110881, Bibcode: 1969AJ.....74..916H. 
  14. ↑ 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. 



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