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44 Boötis

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This article is about i Boötis. Not to be confused with ι Boötis.
44 Boötis

A light curve for 44 Boötis plotted from TESS data[1]
Observation data
Epoch J2000      Equinox J2000
Constellation Boötes
Right ascension 15h 03m 47.29565s[2]
Declination +47° 39′ 14.6228″[2]
Apparent magnitude (V) 4.70 - 4.84[3] (5.136 / 6.004)[4]
Characteristics
Spectral type G0Vnv[5] + (K0V + K4V)[6]
U−B color index 0.09[7]
B−V color index 0.65[7]
Variable type W UMa[3]
Astrometry
Radial velocity (Rv)−17.89[8] km/s
Proper motion (μ) RA: −445.84[2] mas/yr
Dec.: 19.86[2] mas/yr
Parallax (π)78.39 ± 1.03 mas[9]
Distance41.6 ± 0.5 ly
(12.8 ± 0.2 pc)
Absolute magnitude (MV)+2.211[9] / +5.38[10]
Orbit[11]
Primary44 Boo A
Companion44 Boo B
Period (P)209.8±3.3 yr
Semi-major axis (a)3.666±0.021″
Eccentricity (e)0.5111±0.0065
Inclination (i)83.55±0.05°
Longitude of the node (Ω)57.14±0.06°
Periastron epoch (T)B 2012.04±0.26
Argument of periastron (ω)
(secondary)		39.86±0.68°
Orbit[10]
Primary44 Boo Ba
Companion44 Boo Bb
Period (P)0.267818 days
Semi-major axis (a)2.015 R☉
Eccentricity (e)0.0
Inclination (i)72.8°
Semi-amplitude (K1)
(primary)		231.31 km/s
Semi-amplitude (K2)
(secondary)		112.70 km/s
Details
44 Boo A
Mass1.04±0.10[11] M☉
Luminosity1.552[4] L☉
Surface gravity (log g)4.33[12] cgs
Temperature5,877[12] K
Metallicity [Fe/H]−0.24[12] dex
Age1.4–1.5[13] Gyr
44 Boo BA
Mass0.98[14] M☉
Radius0.87[14] R☉
Luminosity0.51[14] L☉
Temperature5,300[14] K
44 Boo Bb
Mass0.55[14] M☉
Radius0.66[14] R☉
Luminosity0.24[14] L☉
Temperature5,035[14] K
Other designations
i Boötis, 40 Boo, BD+48°2259, FK5 3182, GJ 575, HD 133640, HIP 73695, HR 5618, SAO 45357, ADS 9494, CCDM 15038+4739[15]
Database references
SIMBADdata
A
B

44 Boötis or i Boötis is a triple star system in the constellation Boötes. It is approximately 41.6 light years from Earth.

44 Boötis can be resolved into two stars, of 5th and 6th magnitudes respectively. They were separated by 1.5″ when the pair were confirmed in 1819, but were only 0.2″ by 2020 as the two orbit every 210 years.[16][11]

The primary component, 44 Boötis A, is a yellow-white G-type main sequence dwarf with a mean apparent magnitude of +4.83. The companion component, 44 Boötis B, is a W Ursae Majoris variable spectroscopic binary. The variability of this star system was discovered by English astronomer William Herschel.[17] The brightness of the eclipsing binary varies from magnitude +5.8 to +6.40 with a period of 6.43 hours.[18] The two eclipsing components of the system are close enough to allow their stellar envelopes to overlap, or at least nearly so.[10] In 1948, flare behavior was measured from this system based on data from O. J. Eggen.[19]

The 44 Boötis system is 42 light-years (13 parsecs) from Earth.[9] It also may show signs of an infrared excess, implying the existence of a dust disk that absorbs visible light and re-emits it as infrared light. The dust would have a blackbody temperature of about 23 K, situated up to 182 au from the parent star.[4]

References

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  1. ^ "MAST: Barbara A. Mikulski Archive for Space Telescopes". Space Telescope Science Institute. Retrieved 8 December 2021.
  2. ^ a b c d van Leeuwen, F. (November 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.
  3. ^ a b Samus', N. N.; Kazarovets, E. V.; Durlevich, O. V.; Kireeva, N. N.; Pastukhova, E. N. (2017). "General catalogue of variable stars: Version GCVS 5.1". Astronomy Reports. 61 (1): 80. Bibcode:2017ARep...61...80S. doi:10.1134/S1063772917010085. S2CID 125853869.
  4. ^ a b c Montesinos, B.; et al. (September 2016). "Incidence of debris discs around FGK stars in the solar neighbourhood". Astronomy & Astrophysics. 593: 31. arXiv:1605.05837. Bibcode:2016A&A...593A..51M. doi:10.1051/0004-6361/201628329. S2CID 55251562. A51.
  5. ^ Gray, R. O.; Napier, M. G.; Winkler, L. I. (April 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): 2148–2158. Bibcode:2001AJ....121.2148G. doi:10.1086/319956.
  6. ^ Zasche, P.; Wolf, M.; Hartkopf, W. I.; Svoboda, P.; Uhlař, R.; Liakos, A.; Gazeas, K. (2009). "A Catalog of Visual Double and Multiple Stars with Eclipsing Components". The Astronomical Journal. 138 (2): 664. arXiv:0907.5172. Bibcode:2009AJ....138..664Z. doi:10.1088/0004-6256/138/2/664. S2CID 17089387.
  7. ^ a b Mermilliod, J.-C. (1986). "Compilation of Eggen's UBV data, transformed to UBV (unpublished)". Catalogue of Eggen's UBV Data. SIMBAD. Bibcode:1986EgUBV........0M.
  8. ^ Bilir, S.; et al. (February 2005). "Kinematics of W Ursae Majoris type binaries and evidence of the two types of formation". Monthly Notices of the Royal Astronomical Society. 357 (2): 497–517. arXiv:astro-ph/0411291. Bibcode:2005MNRAS.357..497B. doi:10.1111/j.1365-2966.2005.08609.x. S2CID 16274339.
  9. ^ a b c Eker, Z.; et al. (2009). "New absolute magnitude calibrations for W Ursa Majoris type binaries". Astronomische Nachrichten. 330 (1): 68–77. arXiv:0807.4989. Bibcode:2009AN....330...68E. doi:10.1002/asna.200811041. S2CID 15071352.
  10. ^ a b c Lu, Wenxian; Rucinski, Slavek M; Ogłoza, Waldemar (2001). "Radial Velocity Studies of Close Binary Stars. IV". The Astronomical Journal. 122 (1): 402–412. arXiv:astro-ph/0104065. Bibcode:2001AJ....122..402L. doi:10.1086/321131. S2CID 118866197.
  11. ^ a b c Zirm, Henry (2011). "The Rapid Convergence of 44 Boötis with Revised Orbit and Updated Ephemerides" (PDF). Journal of Double Star Observations. 7 (1): 24–36. Bibcode:2011JDSO....7...24Z.
  12. ^ a b c Ramírez, I.; et al. (September 2012). "Lithium Abundances in nearby FGK Dwarf and Subgiant Stars: Internal Destruction, Galactic Chemical Evolution, and Exoplanets". The Astrophysical Journal. 756 (1): 46. arXiv:1207.0499. Bibcode:2012ApJ...756...46R. doi:10.1088/0004-637X/756/1/46. S2CID 119199829.
  13. ^ Mamajek, Eric E.; Hillenbrand, Lynne A. (November 2008). "Improved Age Estimation for Solar-Type Dwarfs Using Activity-Rotation Diagnostics". The Astrophysical Journal. 687 (2): 1264–1293. arXiv:0807.1686. Bibcode:2008ApJ...687.1264M. doi:10.1086/591785. S2CID 27151456.
  14. ^ a b c d e f g h Latković, Olivera; Čeki, Atila; Lazarević, Sanja (2021). "Statistics of 700 Individually Studied W UMa Stars". The Astrophysical Journal Supplement Series. 254 (1): 10. arXiv:2103.06693. Bibcode:2021ApJS..254...10L. doi:10.3847/1538-4365/abeb23. S2CID 232185576.
  15. ^ "* i Boo". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2015-04-22.
  16. ^ Mason, Brian D.; et al. (December 2001). "The 2001 US Naval Observatory Double Star CD-ROM. I. The Washington Double Star Catalog". The Astronomical Journal. 122 (6): 3466–3471. Bibcode:2001AJ....122.3466M. doi:10.1086/323920.
  17. ^ Percy, John R. (2007). Understanding Variable Stars. Cambridge University Press. p. 3. ISBN 978-1139463287.
  18. ^ Malkov, O. Yu.; et al. (2006). "A catalogue of eclipsing variables". Astronomy and Astrophysics. 446 (2): 785–89. Bibcode:2006A&A...446..785M. doi:10.1051/0004-6361:20053137. hdl:10995/73280.
  19. ^ Huruhata, Masaaki (August 1952). "Flaring Phenomena in U Pegasi". Publications of the Astronomical Society of the Pacific. 64 (379): 200. Bibcode:1952PASP...64..200H. doi:10.1086/126463.
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