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44 Boötis

Topic: Astronomy

 From HandWiki - Reading time: 7 min

Short description: Triple star system in the constellation Boötes
44 Boötis
Location of 44 Boötis (circled in red)
Observation data
Equinox J2000.0]] (ICRS)
Constellation Boötes
Right ascension  15h 03m 47.29565s[1]
Declination +47° 39′ 14.6228″[1]
Apparent magnitude (V) 4.70 - 4.84[2] (5.136 / 6.004)[3]
Characteristics
Spectral type G0Vnv[4] + (K0V + K4V)[5]
U−B color index 0.09[6]
B−V color index 0.65[6]
Variable type W UMa[2]
Astrometry
Radial velocity (Rv)−17.89[7] km/s
Proper motion (μ) RA: −445.84[1] mas/yr
Dec.: 19.86[1] mas/yr
Parallax (π)78.39 ± 1.03[8] mas
Distance41.6 ± 0.5 ly
(12.8 ± 0.2 pc)
Absolute magnitude (MV)+2.211[8] / +5.38[9]
Orbit[10]
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[9]
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[10] M☉
Luminosity1.552[3] L☉
Surface gravity (log g)4.33[11] cgs
Temperature5,877[11] K
Metallicity [Fe/H]−0.24[11] dex
Age1.4–1.5[12] Gyr
44 Boo Ba
Mass0.98[13] M☉
Radius0.87[13] R☉
Luminosity0.51[13] L☉
Temperature5,300[13] K
44 Boo Bb
Mass0.55[13] M☉
Radius0.66[13] R☉
Luminosity0.24[13] L☉
Temperature5,035[13] K
Other designations
Quadrans, i Boötis, 44 Boo, BD+48°2259, FK5 3182, GJ 575, HD 133640, HIP 73695, HR 5618, SAO 45357, ADS 9494, CCDM 15038+4739[14]
Database references
SIMBADdata
A
B

44 Boötis, also known as i Boötis, is a triple star system in the constellation Boötes. It is approximately 41.6 light years from Earth. Its three components are designated 44 Boötis A (with the proper name Quadrans[15]), 44 Boötis Ba, and 44 Boötis Bb.

44 Boötis B is a contact binary of the W Ursae Majoris type. It is the nearest contact binary star.[16]

Nomenclature

44 Boötis is the star's Flamsteed designation; it also has the Bayer designation i Boötis.

This star was a member of the obsolete constellation Quadrans Muralis. The IAU Working Group on Star Names approved the name Quadrans for the primary component of the system 44 Boötis A on 17 February 2025, after the obsolete constellation, and it is now so entered in the IAU Catalog of Star Names.[15]

Description

A light curve for 44 Boötis plotted from TESS data[17]

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.[18][10]

The primary component, 44 Boötis A, is a yellow-white G-type main sequence star 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.[19] The brightness of the eclipsing binary varies from magnitude +5.8 to +6.40 with a period of 6.43 hours.[20] The two eclipsing components of the system are close enough to allow their stellar envelopes to overlap, or at least nearly so.[9] In 1948, flare behavior was measured from this system based on data from O. J. Eggen.[21]

A 2016 study reported a possible detection 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. However, this detection was considered dubious by the original study,[3] and a 2019 study reported a non-detection.[22]

References

  1. ↑ 1.0 1.1 1.2 1.3 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. 
  2. ↑ 2.0 2.1 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. doi:10.1134/S1063772917010085. Bibcode: 2017ARep...61...80S. 
  3. ↑ 3.0 3.1 3.2 Montesinos, B. et al. (September 2016). "Incidence of debris discs around FGK stars in the solar neighbourhood". Astronomy & Astrophysics 593: 31. doi:10.1051/0004-6361/201628329. A51. Bibcode: 2016A&A...593A..51M. 
  4. ↑ 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. doi:10.1086/319956. Bibcode: 2001AJ....121.2148G. 
  5. ↑ 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. doi:10.1088/0004-6256/138/2/664. Bibcode: 2009AJ....138..664Z. 
  6. ↑ 6.0 6.1 Mermilliod, J.-C. (1986). "Compilation of Eggen's UBV data, transformed to UBV (unpublished)". Catalogue of Eggen's UBV Data (SIMBAD). Bibcode: 1986EgUBV........0M. 
  7. ↑ 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. doi:10.1111/j.1365-2966.2005.08609.x. Bibcode: 2005MNRAS.357..497B. 
  8. ↑ 8.0 8.1 Eker, Z. et al. (2009). "New absolute magnitude calibrations for W Ursa Majoris type binaries". Astronomische Nachrichten 330 (1): 68–77. doi:10.1002/asna.200811041. Bibcode: 2009AN....330...68E. 
  9. ↑ 9.0 9.1 9.2 Lu, Wenxian; Rucinski, Slavek M; Ogłoza, Waldemar (2001). "Radial Velocity Studies of Close Binary Stars. IV". The Astronomical Journal 122 (1): 402–412. doi:10.1086/321131. Bibcode: 2001AJ....122..402L. 
  10. ↑ 10.0 10.1 10.2 Zirm, Henry (2011). "The Rapid Convergence of 44 Boötis with Revised Orbit and Updated Ephemerides". Journal of Double Star Observations 7 (1): 24–36. Bibcode: 2011JDSO....7...24Z. http://www.jdso.org/volume7/number1/Zirm24_36.pdf. 
  11. ↑ 11.0 11.1 11.2 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. doi:10.1088/0004-637X/756/1/46. Bibcode: 2012ApJ...756...46R. 
  12. ↑ 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. doi:10.1086/591785. Bibcode: 2008ApJ...687.1264M. 
  13. ↑ 13.0 13.1 13.2 13.3 13.4 13.5 13.6 13.7 Latković, Olivera; Čeki, Atila; Lazarević, Sanja (2021). "Statistics of 700 Individually Studied W UMa Stars". The Astrophysical Journal Supplement Series 254 (1): 10. doi:10.3847/1538-4365/abeb23. Bibcode: 2021ApJS..254...10L. 
  14. ↑ "* i Boo". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=%2A+i+Boo. 
  15. ↑ 15.0 15.1 "IAU Catalog of Star Names". https://exopla.net/star-names/modern-iau-star-names/. 
  16. ↑ Gondoin, P. (November 2004). "X-ray spectroscopy of the W UMa-type binary 44 Bootis". Astronomy and Astrophysics 426: 1035-1045. doi:10.1051/0004-6361:20040494. Bibcode: 2004A&A...426.1035G. 
  17. ↑ "MAST: Barbara A. Mikulski Archive for Space Telescopes". Space Telescope Science Institute. https://mast.stsci.edu/portal/Mashup/Clients/Mast/Portal.html. 
  18. ↑ 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. doi:10.1086/323920. Bibcode: 2001AJ....122.3466M. 
  19. ↑ Percy, John R. (2007). Understanding Variable Stars. Cambridge University Press. p. 3. ISBN 978-1139463287. https://books.google.com/books?id=GQzCDQI3YP4C&pg=PA3. 
  20. ↑ Malkov, O. Yu. et al. (2006). "A catalogue of eclipsing variables". Astronomy and Astrophysics 446 (2): 785–89. doi:10.1051/0004-6361:20053137. Bibcode: 2006A&A...446..785M. 
  21. ↑ Huruhata, Masaaki (August 1952). "Flaring Phenomena in U Pegasi". Publications of the Astronomical Society of the Pacific 64 (379): 200. doi:10.1086/126463. Bibcode: 1952PASP...64..200H. 
  22. ↑ Yelverton, Ben; Kennedy, Grant M.; Su, Kate Y. L.; Wyatt, Mark C. (September 2019). "A statistically significant lack of debris discs in medium separation binary systems". Monthly Notices of the Royal Astronomical Society 488 (3): 3588-3606. doi:10.1093/mnras/stz1927. Bibcode: 2019MNRAS.488.3588Y. 



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