HD 130144

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HD 130144
Observation data
Epoch J2000      Equinox J2000
Constellation Boötes
Right ascension 14h 46m 05.94566s[1]
Declination +15° 07′ 54.4332″[1]
Apparent magnitude (V) 5.82[2]
Spectral type M5III[3]
U−B color index +1.26[2]
B−V color index +1.50[2]
Variable type Lb[4]
Radial velocity (Rv) −22.52±0.65[5] km/s
Proper motion (μ) RA: −85.49[1] mas/yr
Dec.: +18.86[1] mas/yr
Parallax (π) 4.04 ± 0.38[1] mas
Distance 810 ± 80 ly
(250 ± 20 pc)
Radius 210±21[3] R
Luminosity 5,587[6] L
Temperature 3,333[6] K
Rotational velocity (v sin i) 11[3] km/s
Other designations
EK Boötis, BD+15° 2758, FK5 3168, HD 130144, HIP 72208, HR 5512, SAO 101200.
Database references

HD 130144 (or EK Boötis) is a semiregular variable star in the northern constellation of Boötes. The variation in luminosity has an amplitude of 0.38 in magnitude with no apparent periodicity. This is an X-ray source, and was possibly the first M-type giant star to have a magnetic field directly detected. It is considered to be a single star,[3] although there is nearby companion at an angular separation of 0.2023 along a position angle of 82.2° (as of 2010.4812).[7]


  1. ^ a b c d e van Leeuwen, F. (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv:0708.1752free to read, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357 
  2. ^ a b c Mermilliod, J.-C. (1986), "Compilation of Eggen's UBV data, transformed to UBV (unpublished)", Catalogue of Eggen's UBV data. SIMBAD, Bibcode:1986EgUBV........0M 
  3. ^ a b c d Konstantinova-Antova, R.; Aurière, M.; Charbonnel, C.; Drake, N. A.; Schröder, K.-P.; Stateva, I.; Alecian, E.; Petit, P.; Cabanac, R. (December 2010), "Direct detection of a magnetic field in the photosphere of the single M giant EK Bootis. How common is magnetic activity among M giants?", Astronomy and Astrophysics, 524: 9, arXiv:1009.2001free to read, Bibcode:2010A&A...524A..57K, doi:10.1051/0004-6361/201014503, A57 
  4. ^ Samus, N. N.; Durlevich, O. V.; et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)". VizieR On-line Data Catalog: B/gcvs. Originally published in: 2009yCat....102025S. 1. Bibcode:2009yCat....102025S. 
  5. ^ Famaey, B.; et al. (2009), "Spectroscopic binaries among Hipparcos M giants,. I. Data, orbits, and intrinsic variations", Astronomy and Astrophysics, 498 (2): 627–640, arXiv:0901.0934free to read, Bibcode:2009A&A...498..627F, doi:10.1051/0004-6361/200810698 
  6. ^ a b McDonald, I.; Zijlstra, A. A; Boyer, M. L. (2012). "Fundamental Parameters and Infrared Excesses of Hipparcos Stars". Monthly Notices of the Royal Astronomical Society. 427 (1): 343–57. arXiv:1208.2037free to read. Bibcode:2012MNRAS.427..343M. doi:10.1111/j.1365-2966.2012.21873.x. 
  7. ^ Horch, Elliott P.; et al. (February 2011), "Observations of Binary Stars with the Differential Speckle Survey Instrument. II. Hipparcos Stars Observed in 2010 January and June", The Astronomical Journal, 141 (2): 13, Bibcode:2011AJ....141...45H, doi:10.1088/0004-6256/141/2/45, 45 

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