38 Lyncis

38 Lyncis is a multiple star system in the northern constellation of Lynx. It located about 125 light-years from the Sun, based on parallax.

38 Lyncis
Observation data
Epoch J2000      Equinox J2000
Constellation Lynx
Right ascension 09h 18m 50.64384s[1]
Declination +36° 48′ 09.3331″[1]
Apparent magnitude (V) 3.82[2] (3.95 + ? + 6.30)[3]
Characteristics
Spectral type A3V[4] (A1V + A4V)[5]
B−V color index 0.066±0.010[2]
Astrometry
Radial velocity (Rv)4.0±2.7[2] km/s
Absolute magnitude (MV)+0.98[6]
A
Proper motion (μ) RA: –36.288[7] mas/yr
Dec.: −121.767[7] mas/yr
Parallax (π)27.8044 ± 0.7879[7] mas
Distance117 ± 3 ly
(36 ± 1 pc)
B
Proper motion (μ) RA: –26.513[8] mas/yr
Dec.: −127.261[8] mas/yr
Parallax (π)24.4730 ± 0.1240[8] mas
Distance133.3 ± 0.7 ly
(40.9 ± 0.2 pc)
Details
38 Lyn A
Mass1.90[9] M☉
Radius3.07[10] R☉
Luminosity32[6] L☉
Surface gravity (log g)3.86[9] cgs
Temperature8,862±301[9] K
Metallicity [Fe/H]−0.36[11] dex
Rotational velocity (v sin i)163[11] km/s
Age213[9] Myr
38 Lyn B
Mass1.30/0.90[12] M☉
Radius2.55[8] R☉
Luminosity5[8] L☉
Temperature5,409[8] K
Other designations
38 Lyn, BD+37°1965, FK5 346, HD 80081, HIP 45688, HR 3690, SAO 61391, WDS J09188+3648[13]
Database references
SIMBADdata
A
B

When viewed through a moderate telescope, two components—a brighter blue-white star of magnitude 3.9 and a fainter star of magnitude 6.1 that has been described as lilac as well as blue-white—can be seen.[14] The pair have an angular separation of 2.6″ and an estimated period of 429 years.[12] The fainter component is itself a close binary which can only be resolved using speckle interferometry. The two were separated by 0.06″ in 1993[15] and 0.237″ in 2008,[16] and have an estimated orbital period of 2.1 years.[12] A further faint star, component E 100″ away, is a proper-motion companion.[17][18] Two other faint companions listed in multiple star catalogues as components C and D are unrelated background objects.[19][20]

38 Lyncis was given as a standard star for the spectral class of A3 V when the Morgan-Keenan classification system was first defined in 1943, apparently for the two components combined.[21]

The primary star, component A, is a class A main sequence star around twice the mass of the sun. An effective temperature of 8,862 K and a radius of 3.09 R☉ mean that it is over thirty times more luminous than the sun. It has been listed as a λ Boötis star, although it is no longer considered to be a member.[6] The fainter of the pair, component B, has been given a spectral class of A4V, although it consists of two very close stars. Their properties are poorly-known, even the difference in their apparent magnitudes can only be estimated to be approximately 2. Based on this, their masses are estimated to be 1.3 M☉ and 0.9 M☉ respectively.[12] Component E is a 15th magnitude star with an approximate spectral type of M2, a red dwarf, and an estimated mass of 0.31 M☉,[12] and a temperature of 3,816 K.[18]

References
  1. van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653–664. arXiv:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. S2CID 18759600.
  2. Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters. 38 (5): 331. arXiv:1108.4971. Bibcode:2012AstL...38..331A. doi:10.1134/S1063773712050015. S2CID 119257644.
  3. 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. arXiv:0806.2878. Bibcode:2008MNRAS.389..869E. doi:10.1111/j.1365-2966.2008.13596.x. S2CID 14878976.
  4. Cowley, A.; et al. (April 1969). "A study of the bright A stars. I. A catalogue of spectral classifications". Astronomical Journal. 74: 375–406. Bibcode:1969AJ.....74..375C. doi:10.1086/110819.
  5. Palmer, D. R.; et al. (1968). "The radial velocities spectral types and projected rotational velocities of 633 bright northern A stars". Royal Observatory Bulletin. 135: 385. Bibcode:1968RGOB..135..385P.
  6. Murphy, Simon J.; Paunzen, Ernst (2017). "Gaia's view of the λ Boo star puzzle". Monthly Notices of the Royal Astronomical Society. 466 (1): 546–555. arXiv:1612.01528. Bibcode:2017MNRAS.466..546M. doi:10.1093/mnras/stw3141. S2CID 119328659.
  7. Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
  8. Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
  9. David, Trevor J.; Hillenbrand, Lynne A. (2015). "The Ages of Early-Type Stars: Strömgren Photometric Methods Calibrated, Validated, Tested, and Applied to Hosts and Prospective Hosts of Directly Imaged Exoplanets". The Astrophysical Journal. 804 (2): 146. arXiv:1501.03154. Bibcode:2015ApJ...804..146D. doi:10.1088/0004-637X/804/2/146. S2CID 33401607.
  10. Gáspár, András; Rieke, George H.; Ballering, Nicholas (2016). "The Correlation Between Metallicity and Debris Disk Mass". The Astrophysical Journal. 826 (2): 171. arXiv:1604.07403. Bibcode:2016ApJ...826..171G. doi:10.3847/0004-637X/826/2/171. S2CID 119241004.
  11. Takeda, Yoichi; Kang, Dong-Il; Han, Inwoo; Lee, Byeong-Cheol; Kim, Kang-Min (2009). "Can Sodium Abundances of A-Type Stars be Reliably Determined from Na I 5890/5896 Lines?". Publications of the Astronomical Society of Japan. 61 (5): 1165–1178. arXiv:0907.1329. Bibcode:2009PASJ...61.1165T. doi:10.1093/pasj/61.5.1165. S2CID 15454888.
  12. "Multiple Star Catalog". Retrieved 2019-06-08.
  13. "38 Lyncis". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-06-06.
  14. Monks, Neale (2010). Go-To Telescopes Under Suburban Skies. New York, New York: Springer Science & Business Media. p. 58. ISBN 9781441968517.
  15. McAlister, Harold A.; Mason, Brian D.; Hartkopf, William I.; Shara, Michael M. (1993). "ICCD speckle observations of binary stars. X - A further survey for duplicity among the bright stars". The Astronomical Journal. 106: 1639. Bibcode:1993AJ....106.1639M. doi:10.1086/116753.
  16. Hartkopf, William I.; Mason, Brian D.; Rafferty, Theodore J. (2008). "Speckle Interferometry at the Usno Flagstaff Station: Observations Obtained in 2003-2004 and 17 New Orbits". The Astronomical Journal. 135 (4): 1334–1342. Bibcode:2008AJ....135.1334H. doi:10.1088/0004-6256/135/4/1334.
  17. De Rosa, R. J.; Patience, J.; Wilson, P. A.; Schneider, A.; Wiktorowicz, S. J.; Vigan, A.; Marois, C.; Song, I.; MacIntosh, B.; Graham, J. R.; Doyon, R.; Bessell, M. S.; Thomas, S.; Lai, O. (2014). "The VAST Survey – III. The multiplicity of A-type stars within 75 pc". Monthly Notices of the Royal Astronomical Society. 437 (2): 1216–1240. arXiv:1311.7141. Bibcode:2014MNRAS.437.1216D. doi:10.1093/mnras/stt1932. S2CID 88503488.
  18. Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
  19. Mason, B. D.; et al. (2014). "The Washington Visual Double Star Catalog". The Astronomical Journal. 122: 3466–3471. Bibcode:2001AJ....122.3466M. doi:10.1086/323920. Retrieved 2015-07-22.
  20. Dommanget, J.; Nys, O. (1995). "Catalogue of the components of double and multiple stars (CCDM)- First edition, June 1994". Bulletin d'Information du Centre de Données Stellaires. 46: 3. Bibcode:1995BICDS..46....3D.
  21. Morgan, William Wilson; Keenan, Philip Childs; Kellman, Edith (1943). "An atlas of stellar spectra, with an outline of spectral classification". Chicago. Bibcode:1943MKAtl.C......0M.
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