Astronomy:Iota Lyrae

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Short description: Binary star in the constellation Lyra
Iota Lyrae
Location of ι Lyrae (circled in red)
Observation data
Equinox J2000.0]] (ICRS)
Constellation Lyra
Right ascension  19h 07m 18.13251s[1]
Declination +36° 06′ 00.5592″[1]
Apparent magnitude (V) 5.22[2]
Characteristics
Spectral type B6IV[3]
Variable type Be star[4]
Astrometry
Radial velocity (Rv)−26.0±4.6[5] km/s
Proper motion (μ) RA: −1.437[1] mas/yr
Dec.: −3.876[1] mas/yr
Parallax (π)3.5858 ± 0.1924[1] mas
Distance910 ± 50 ly
(280 ± 10 pc)
Absolute magnitude (MV)−1.94[6]
Orbit[7]
Period (P)216.93 yr
Semi-major axis (a)0.172″
Eccentricity (e)0.637
Inclination (i)145.5°
Longitude of the node (Ω)171.4°
Periastron epoch (T)B 1997.28
Argument of periastron (ω)
(secondary)		201.2°
Details
Mass5.2[8] M☉
Radius6.7[9] R☉
Luminosity854[9] L☉
Surface gravity (log g)3.54[8] cgs
Temperature12,059[9] K
Metallicity [Fe/H]−0.11[8] dex
Rotational velocity (v sin i)224[10] km/s
Age168[11] Myr
Other designations
ι Lyr, 18 Lyr, BD+35°3485, GC 26338, HD 178475, HIP 93903, HR 7262, SAO 67834, WDS 19073+3606, GSC 02652-01709[12]
Database references
SIMBADdata

ι Lyrae, Latinised as Iota Lyrae, is a binary star[2] in the northern constellation of Lyra. It is visible to the naked eye as a dim, blue-white hued star with an apparent visual magnitude that fluctuates around 5.22.[2] This object is located approximately 910 light years distant from the Sun based on parallax, but is drifting nearer with a radial velocity of −26 km/s.[5]

A light curve for Iota Lyrae, plotted from TESS data[13]

This is a wide binary system with a computed orbital period of 217 years and an eccentricity of 0.6.[7] The primary component has a stellar classification of B6IV,[3] matching a B-type subgiant star. It is a Be star,[14] displaying emission lines in its spectrum, and is spinning rapidly with a projected rotational velocity of 224 km/s.[10] The star ranges in brightness from magnitude 5.20 down to 5.27.[4] It has about five times the mass of the Sun and is radiating 854 times the Sun's luminosity from its photosphere at an effective temperature of 12,059 K.

References

  1. ↑ 1.0 1.1 1.2 1.3 1.4 Brown, A. G. A. (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics 616: A1. doi:10.1051/0004-6361/201833051. Bibcode: 2018A&A...616A...1G.  Gaia DR2 record for this source at VizieR.
  2. ↑ 2.0 2.1 2.2 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. 
  3. ↑ 3.0 3.1 Lesh, Janet Rountree (December 1968). "The Kinematics of the Gould Belt: an Expanding Group?". Astrophysical Journal Supplement 17: 371. doi:10.1086/190179. Bibcode: 1968ApJS...17..371L. 
  4. ↑ 4.0 4.1 Samus, N. N. et al. (2017), "General Catalogue of Variable Stars", Astronomy Reports, 5.1 61 (1): 80–88, doi:10.1134/S1063772917010085, Bibcode: 2017ARep...61...80S. 
  5. ↑ 5.0 5.1 Gontcharov, G. A. (November 2006). "Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system". Astronomy Letters 32 (11): 759–771. doi:10.1134/S1063773706110065. Bibcode: 2006AstL...32..759G. 
  6. ↑ Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters 38 (5): 331. doi:10.1134/S1063773712050015. Bibcode: 2012AstL...38..331A. 
  7. ↑ 7.0 7.1 "Sixth Catalog of Orbits of Visual Binary Stars". United States Naval Observatory. http://www.usno.navy.mil/USNO/astrometry/optical-IR-prod/wds/orb6. 
  8. ↑ 8.0 8.1 8.2 Anders, F. et al. (August 2019). "Photo-astrometric distances, extinctions, and astrophysical parameters for Gaia DR2 stars brighter than G = 18". Astronomy & Astrophysics 628: A94. doi:10.1051/0004-6361/201935765. ISSN 0004-6361. Bibcode: 2019A&A...628A..94A. 
  9. ↑ 9.0 9.1 9.2 McDonald, I.; Zijlstra, A. A.; Watson, R. A. (15 June 2017). "Fundamental parameters and infrared excesses of Tycho–Gaia stars". Monthly Notices of the Royal Astronomical Society 471 (1): 770–791. doi:10.1093/mnras/stx1433. ISSN 0035-8711. Bibcode: 2017MNRAS.471..770M. 
  10. ↑ 10.0 10.1 Zorec, J.; Royer, F. (2012). "Rotational velocities of A-type stars. IV. Evolution of rotational velocities". Astronomy & Astrophysics 537: A120. doi:10.1051/0004-6361/201117691. Bibcode: 2012A&A...537A.120Z. 
  11. ↑ Gontcharov, G. A. (December 2012). "Dependence of kinematics on the age of stars in the solar neighborhood". Astronomy Letters 38 (12): 771–782. doi:10.1134/S1063773712120031. ISSN 0320-0108. Bibcode: 2012AstL...38..771G. 
  12. ↑ "iot Lyr". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=iot+Lyr. 
  13. ↑ "MAST: Barbara A. Mikulski Archive for Space Telescopes". Space Telescope Science Institute. https://mast.stsci.edu/portal/Mashup/Clients/Mast/Portal.html. 
  14. ↑ Abt, H. A.; Cardona, O. (October 1984), "Be stars in binaries", Astrophysical Journal 285: 190–194, doi:10.1086/162490, Bibcode: 1984ApJ...285..190A 



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