Iota Virginis

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Iota Virginis
Virgo IAU.svg
Cercle rouge 100%.svg

Location of ι Virginis.
Observation data
Epoch J2000      Equinox J2000
Constellation Virgo
Right ascension 14h 16m 00.86951s[1]
Declination −06° 00′ 01.9633″[1]
Apparent magnitude (V) 4.08[2]
Characteristics
Spectral type F7IV-V[3]
U−B color index +0.02[4]
B−V color index +0.52[4]
Astrometry
Radial velocity (Rv) 12.51 ± 0.18[5] km/s
Proper motion (μ) RA: -26.31[1] mas/yr
Dec.: -419.38[1] mas/yr
Parallax (π) 44.97 ± 0.19[1] mas
Distance 72.5 ± 0.3 ly
(22.24 ± 0.09 pc)
Absolute magnitude (MV) 2.4[3]
Orbit[3]
Period (P) 55 yr
Semi-major axis (a) 0.830 ± 0.020″
Eccentricity (e) 0.1 ± 0.2
Inclination (i) 60 ± 9°
Longitude of the node (Ω) 3 ± 20°
Periastron epoch (T) 1950.7 ± 2.7
Argument of periastron (ω)
(secondary)
336 ± 27°
Details
ι Vir A
Mass 1.5 ± 0.05[3] M
Radius 2.5[6] R
Luminosity 8.7[6] L
Surface gravity (log g) 3.94[7] cgs
Temperature 6282[7] K
Metallicity [Fe/H] −0.11[7] dex
Rotational velocity (v sin i) 16[3] km/s
ι Vir B
Mass 0.6 ± 0.2[3] M
Other designations
Syrma, 99 Vir, BD−05° 3843, FK5 525, GJ 9473, HD 124850, HIP 69701, HR 5338, SAO 139824
Database references
SIMBAD data

Iota Virginis (ι Virginis, abbreviated Iota Vir, ι Vir), also named Syrma,[8] is a binary star in the constellation of Virgo. Its apparent magnitude is 4.08.[2] Based on its parallax, it is assumed to be relatively nearby, at 72.5 light-years (22.24 parsecs).[1]

Nomenclature[edit]

ι Virginis (Latinised to Iota Virginis) is the star's Bayer designation.

It bore the traditional name Syrma, derived from the Arabic سرما (تطريز sirmā "train (of a garment)".[9] In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN)[10][11][12] to catalogue and standardize proper names for stars. The WGSN approved the name Syrma for this star on 12 September 2016 and it is now so entered in the IAU Catalog of Star Names.[8]

In China, 亢宿 (Kàng Xiù), meaning Neck, refers to an asterism consisting of this star, Kappa Virginis, Phi Virginis and Lambda Virginis.[13] Consequently, Iota Virginis itself is known as 亢宿二 (Kàngsuèr, English: the Second Star of Neck.)

Properties[edit]

Iota Virginis is a yellow-colored star with a spectral class of F7IV-V. This star has 1.5 times the mass of the Sun, with a projected rotational velocity of 16 km s−1.[3] It is radiating 8.7 times the luminosity of the Sun[6] from its outer atmosphere at an effective temperature of 6,282 K.[7] The radius is about 2.5 times that of the Sun.[6]

Iota Virginis is also an astrometric binary. Its companion regularly perturbs the primary, causing the primary to wobble around its barycenter.[3] A preliminary orbit with a period of 55 years has been calculated.[3] The companion star to Iota Virginis has not been directly detected, but based on its mass (0.6 M) it may be a main-sequence star or a white dwarf.[3] That star is also responsible for the drifting radial velocity of the primary.[14]

In 2011, it was noticed that the faint K-type main-sequence star HD 125354 had a similar proper motion throughout space, and was likely physically associated.[15] Another 2015 paper supported this hypothesis. The star, which is located 1.2 ly (0.37 pc) away from Iota Virginis, also has a similar distance, within the margin of error. It itself is a close binary with another star separated 0.33″ from the main star.[16]

References[edit]

  1. ^ a b c d e f van Leeuwen, F.; et al. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653–664. Bibcode:2007A&A...474..653V. arXiv:0708.1752Freely accessible. doi:10.1051/0004-6361:20078357. 
  2. ^ a b Gray, R. O.; Napier, M. G.; Winkler, L. I. (2001). "The Physical Basis of Luminosity Classification in the Late A-, F-, and Early G-Type Stars. I. Precise Spectral Types for 372 Stars". The Astronomical Journal. 121 (4): 2148. Bibcode:2001AJ....121.2148G. doi:10.1086/319956. 
  3. ^ a b c d e f g h i j Gontcharov, G.A.; Kiyaeva, O.V. (2010). "Photocentric orbits from a direct combination of ground-based astrometry with Hipparcos II. Preliminary orbits for six astrometric binaries". New Astronomy. 15 (3): 324. Bibcode:2010NewA...15..324G. arXiv:1606.08182Freely accessible. doi:10.1016/j.newast.2009.09.006. 
  4. ^ a b Mermilliod, J.-C. (1986). "Compilation of Eggen's UBV data, transformed to UBV (unpublished)". Catalogue of Eggen's UBV data. Bibcode:1986EgUBV........0M. 
  5. ^ Maldonado, J.; Martínez-Arnáiz, R. M.; Eiroa, C.; Montes, D.; Montesinos, B. (2010). "A spectroscopy study of nearby late-type stars, possible members of stellar kinematic groups". Astronomy and Astrophysics. 521: A12. Bibcode:2010A&A...521A..12M. arXiv:1007.1132Freely accessible. doi:10.1051/0004-6361/201014948. 
  6. ^ a b c d Malagnini, M. L.; Morossi, C. (November 1990). "Accurate absolute luminosities, effective temperatures, radii, masses and surface gravities for a selected sample of field stars". Astronomy and Astrophysics Supplement Series. 85 (3): 1015–1019. Bibcode:1990A&AS...85.1015M. 
  7. ^ a b c d Mallik, Sushma V. (December 1999). "Lithium abundance and mass". Astronomy and Astrophysics. 352: 495–507. Bibcode:1999A&A...352..495M. 
  8. ^ a b "IAU Catalog of Star Names". Retrieved 28 July 2016. 
  9. ^ Allen, R. H., (1963). Star Names: Their Lore and Meaning (Reprint ed.). New York, NY: Dover Publications Inc. p. 472. ISBN 0-486-21079-0. 
  10. ^ IAU Working Group on Star Names (WGSN), International Astronomical Union, retrieved 22 May 2016. 
  11. ^ IAU Formally Approves 227 Star Names, International Astronomical Union, retrieved 24 November 2016. 
  12. ^ NAMING STARS: List of IAU-approved Star Names as of 24.11.2016, International Astronomical Union, retrieved 24 November 2016. 
  13. ^ (in Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 6 月 28 日
  14. ^ Borgniet, S.; Lagrange, A.-M.; Meunier, N.; Galland, F. (2017). "Extrasolar planets and brown dwarfs around AF-type stars". Astronomy & Astrophysics. 599: A57. Bibcode:2017A&A...599A..57B. arXiv:1608.08257Freely accessible. doi:10.1051/0004-6361/201628805. 
  15. ^ Shaya, Ed J.; Olling, Rob P. (January 2011). "Very Wide Binaries and Other Comoving Stellar Companions: A Bayesian Analysis of the Hipparcos Catalogue". The Astrophysical Journal Supplement. 192 (1): 2. Bibcode:2011ApJS..192....2S. arXiv:1007.0425Freely accessible. doi:10.1088/0067-0049/192/1/2. 
  16. ^ Fuhrmann, K.; Chini, R. (2015). "Multiplicity Among F-Type Stars. II". The Astrophysical Journal. 809: 107. Bibcode:2015ApJ...809..107F. doi:10.1088/0004-637X/809/1/107. 

External links[edit]